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VoteVerifier

1. 83 Day s 15 Dayls Ll x o o oo o 22 Day s 6 SS Sg Ss df L15 Day s 11 7 Day s lo 21 Day s 7 IR Sg I 18 Day s 12 SS Sa 8 Day s 1 3 20 Day s 3 r a 13 Day s 10 FE Sa 7 Dayls 5 L4 Da sil VoteVerifier Independent Verifier for UniVote Elections Table 1 Planning of the development Task Description Documentation The documentation is long as the project duration because we always write some portions of it Planning The planning is the first step of the project and will help us by defining the guide lines for the future tasks First Iteration For the first iteration we have planned the developing of the crypto primitives These are the basis for the future tasks and they include for example the ability to verify an RSA signature of a non interactive zero knowledge proof After each iteration there will be a phase of test developing in order to provide to the next iteration a code that is fully operational Second Iteration Here we planned to build the infrastructure used to communicate with the election board of UniVote This means that after this step we will be able to perform the verification of an election by downloading the necessary data This step also includes the implementation of the different cryptographic computations Third Iteration
2. During this last iteration we have to design and develop the graphical user interface This means that we have to integrate the code of the iteration 2 and at the end we will have the complete software Release This is the final phase where some minor works will be done such as packing the software into an installer We basically followed the plan that was created at the start of the project The only considerable deviation involves the second iteration Here we thought that due to the lack of time and the important amount of work for the GUI to split the work between us So during the second iteration Mr Scalzi developed the structure of the software in order to communicate and perform a verification while Mr Springer designed and implemented the GUI By doing this we were able to intercept some possible problems in an early stage of development VoteVerifier Independent Verifier for UniVote Elections 666 Fr 1 6 Results In the course of development we were able to meet all of the original requirements set at the beginning of the project We were successfully able to create a simple and user friendly graphical user interface which allows the user to create two different verification types to verify the results of election held by UniVote e voting systems Illustration 1 3 The results of the verification process are shown in a table File View Language Schnorr s g is a generator Schnorr s p is
3. the public board private void getElectionBoard ElectionBoardService ebs new ElectionBoardService wsdlURL eb ebs getElectionBoardPort The ElectionBoardService is an artifact generated during the creation of the web service client and give us back an object of the type ElectionBoardPort which is really used to communicate with the other party We now explain the simple cache mechanism introduced at the beginning The concept is simple We want to return an object that has already been created so that we avoid the creation of a new one and as a result do not have to download all the data once again We can explain the situation with a practical example public Ballots getBallots throws ElectionBoardServiceFault if ballots null ballots eb getBallots eID return ballots This method is used to get the ballots of an election We can see that thanks to the if statement we can control the access to the object ballots At the first call the object will be null and we will use the previously created ElectionBoardPort object to get the ballots from the network When someone calls getBallots one more time we can deliver the previously created ballots object This mechanism speeds up the verification process because we need the same data in different points of the software VoteVerifier Independent Verifier for UniVote Elections 3C 3 10 Customization of Messages In our software it
4. this method is that it must be impossible for the verifier to gain the access to the value that has to be verified This because otherwise it will be clearly too trivial to prove the knowledge of the value We can distinguish between Zero Knowledge Proof and non interactive zero knowledge proof by saying that in the first case interaction is needed between the verifier and the prover where in the second not UniVote uses only the non interactive variant NIZKP are mainly used in UniVote to prove the knowledge a particular discrete logarithm 2 1 5 Certificates UniVote uses X 509 certificates in order to prove the identity of the different parties involved during the voting process The parties include a certificate authority CA an election administrator EA an election manager EM some talliers T some mixers M and the voters V Each of these entities has a certificate and each of them has a public key used for example to generate the various signatures involved 2 2 UniVote s Voting Process In this paragraph we want to briefly explain the voting process of UniVote First of all we want to explain the different entities involved Each entity plays a precise role and we want to briefly describe each of them e Certificate Authority CA this entity is at the top of the hierarchy and is as a trust of anchor for the others Election Manager EM as the name says it manages an election It verifies the c
5. 5d ParametersImplementer 380 EL_PREP_PUB_VER_KEYS_SIGN 1 3 5d EM RSAlmplementer EL PERIOD LATE NEW _ VOTER CERT CertificatesImplementer EL_PERIOD_LATE_NEW_VOTER_CERT_SI 136a EM GN Se PERIOD_M_NIZKP_EQUALITY_NEW_V Prooflmplementer EN o RSAlmplementer VoteVerifier Independent Verifier for UniVote Elections EL PERIOD M NIZKP EQUALITY NEW V RF SIGN EL PERIOD NEW VER KEY ParametersImplementer aR PERIOD_M_VER_KEY_NIZKP_OF_ALP 136b Prooflmplementer M EL_PERIOD_M_VER_KEY_NIZKP_OF_ALP r HA SIGN 1 3 6 b RSAlmplementer M EL_PERIOD_LAST_M_VER_KEY 1 3 6 b ParametersImplementer EL_PERIOD_LAST_M_VER_KEY_SIGN 1 3 6b RSAImplementer 450 EL_PERIOD_BALLOT 1 3 6 d ElectionPeriodRunner 455 EL_PERIOD_BALLOT_SIGN 1 3 6 d RSAImplementer 500 IMT M ENC VOTES SET Prooflmplementer 550 MT VALID PLAINTEXT VOTES 1 3 7 b Parametersimplementer 560 MT VALID PLAINTEXT_ VOTES SIGN 1 3 7 b RSAlmplementer 415 136 a Mixer RSAlmplementer VoteVerifier Independent Verifier for UniVote Elections 12 600 SINGLE BALLOT RSA SIGN QR Code E RSAlmplementer M SINGLE BALLOT IN BALLOTS ParametersImplementer SINGLE_BALLOT_VERIFICATION_KEY ParametersImplementer SINGLE_BALLOT_PROOF Prooflmplementer SINGLE BALLOT SCHNORR SIGN Schnorrlmplementer 2 4 Graphical User Interface The GUI is organized into three sections the title panel at the top and the main content panel i
6. As a programming language we have used Java This was beneficial first of all because it is a language that we had previously learned and secondly it offers flexibility in terms of software development In addition a Java program can be used on every platform by installing a Java Virtual Machine so our software is not bound to a particular architecture or operating system 3 1 2 Maven Maven as the projects website says is a is a software project management and comprehension tool We have used by suggestion of Dr Dubuis Thanks to Maven we are able to generate project builds in a faster and cleaner way In addition it manages all the importation and downloading of additional libraries Thanks to the cobertura plugin we can also generate test reports and other types of report 3 1 3 Web Services In order to get the data from the public board we have used the web service provided by UniVote Thanks to this technology we can easily communicate with another system without having to worry about managing the communication For this purpose we have created in our project a Web Service Client by giving the address of the board http univote ch 8080 ElectionBoardService ElectionBoardServicelmpl wsdl After the creation the artifacts from UniVote will be created and made available in our project Then we can send SOAP requests and use the data directly as Java objects so we don t have to parse any kind of file 3 1 4 Git As version
7. There are of course some minor improvements that could be made which would render the software even more effective user friendly and efficient e The internationalization should be extended to include all verification results and additional information e The additional information of a tooltip should be placed in a separate properties files because as it stands today these are hard coded inside Implementer classes 4 2 Acquired Knowledge In this project we deepened our knowledge of software development including the planning and organization of a large scale Bachelor project We learned first hand how creating a clear and specific plan at the beginning of the project can help guide the development of the software and also how it can keep the progress on track It is sometimes easy to get lost in small details of a project but while working under pressure we were able to keep and eye on the plan and make sure the most central features of the project received the most attention Our knowledge of cryptography especially signatures encryption and zero knowledge proofs has also increased Above all it was interesting to see how these different aspects of cryptography and security interact to create a secure system Up until now most of our knowledge had regarded individual cases of each technology but after this project it is much more clear how different security features compliment each other and can be used together This was our
8. can switch back after a verification process has begun VoteVerifier Independent Verifier for UniVote Elections 2 4 1 Interpreting Results There are 4 possible outcomes for the verification results A result may pass fail not be implemented or have caused an error In the case that the result passed the verification a green checkmark will appear at the end of the line where the verification is described If the verification was unsuccessful then in place of a green checkmark a red x will appear The two remaining results are special cases in which either the UniVote team has not yet implemented the content for the verification or an error occurred during the processing of the verification If a verification has yet to be implemented an orange question mark will be shown If an error was produced then a yellow warn symbol is shown In any case except a successful result additional information about why the test failed and what this means can be obtained through the Helper Text More information about this feature is available in the section Helper Text After a verification has been completed a Verification Event object is sent to the GUI over the Messenger class The Verification Event is a helper class which contains various results from the verification An algorithm evaluates the Verification Event to decide which image should be shown and which information should be added into a pop up helper text Below is a table which il
9. disappears 3 The next tab to the left becomes the active visible tab 4 The thread that was running the verification for the closed tab is interrupted Use case 12 Use Case UC12 Sort Election Verification Results Primary Actor Voter VoteVerifier Independent Verifier for UniVote Elections 41 Success Guarantee The user clicks on a sort option for the verificaiton results and sees the corresponding organization in the results window Preconditions The user has started a verification which may be running or terminated Main Success Scenario 1 The user clicks on one of the three organization options above the area where verification results are being displayed 2 The verification results are reorganized according to the selected organisation Use case 13 Use Case UC13 View Candidate Election Results Primary Actor Voter Success Guarantee The user sees the results for the election in the results window Preconditions The user has started a verification which may be running or terminated Main Success Scenario 1 The user clicks on the button Election Results 2 The results for the votes for the candidates are displayed VoteVerifier Independent Verifier for UniVote Elections B User Manual The user manual is available to the user through the help menu from within the program It describes how to proceed to start both a universal and individual verification process as well as how to understan
10. first experience with the maven build manager and through its use we have come to appreciate what a great service it provides From being able to manage the project details to quickly adding external add ons such as ZXing or Web Services Maven really makes development easier Finally it was a great project to be able to deepen out knowledge of GUI development This was the first GUI that we designed and it is clear that some problems cannot be explained in advanced when it comes to GUI development Rather they must be experienced before they can be rightly appreciated understood and avoided in the future Now that the GUI is complete it would be nice to be able to go back to square one and rebuild it in a cleaner and more organized fashion VoteVerifier Independent Verifier for UniVote Elections Bibliography 1 R Haenni UniVote System Specification 2013 Online Available http e voting bfh ch app download 5874743461 specification pdf t 1365082914 2 G Scalzi J Springer S B rtsch Bases de math matique cryptographie asym trique et preuves divulgation nulle de connaissance Semester Project Project 2 2013 VoteVerifier Independent Verifier for UniVote Elections 3 A Use Cases List of the Actors The verification in VoteVerifier involves only one actor who initiates a desired verification type After the initial setup phase all functionality is automated and involves only the fetching of
11. of Applied Sciences VoteVerifier was developed independently from yet in cooperation with the UniVote electronic voting system The voting secret and correctness of the election results are protected cryptographically By publicizing the cryptographically protected election data the results of the election can later be scrutinized by independent parties VoteVerifier Independent Verifier for UniVote Elections Illustration 1 1 The flow of the information from generation to VoteVerifier results The voters cast their votes in an UniVote election The votes are processed When the election period ends following the specification the result are published on the public board voterl voter2 Everybody can verify the results in order to trust UniVote independant people 1 3 Goal The main goal of the software we have to develop is to verify election results from the UniVote e voting system To this end the software should provide a quick and simple tool to accompany and reinforce the validity of the UniVote e voting system A graphical user interface GUI should provide a user friendly attractive appearance for users to input the parameters to start a verification process and the results should be displayed clearly and in an organized fashion The manner in which the program evaluates a verification should be created in strict adherence to the specification from the UniVote system To test the program results from real electi
12. off life can be connected in some way to the use of the Internet From ordering DVDs to watching them online from researching a topic to planning a vacation there is no end to the timesaving conveniences that appear on the Internet It is therefore no small wonder that the lengthy and arduous process of holding an election be made more convenient by creating a safe and secure service to hold elections electronically Perhaps the issue of electronic voting however deserves the most emphasis on security than any other branch of life that could be placed on the Internet Although e voting presents a great advantage compared to traditional voting systems it poses an equally great risk that the results could be covertly changed For all the time saving that an e voting system can offers if the system could be hacked it would represent a huge temptation for opposing parties to try to easily manipulate the results of an election Were a party successfully able to compromise the voting system it would take little effort to swing the results of an election into their own favor and causing profound effects on the future of schools countries and the world For this reason e voting systems are implemented with strong security measures which rely on proven and effective cryptographic functions The UniVote system for example additionally implements a system of checks on every critical step of the election process Using mathematical proofs the veracity a
13. show console Ce Lcome to UniVerifier Please select a verification type and click start 3 3 Language Menu VoteVerifier supports use in English German and French The language can be changed through the Language menu in which the options for the available languages appear Upon clicking on one of the options the program s visual content will be rebuilt with the text in the newly selected language It is important not to change the language while a verification is in progress or the progress will be lost and the verification will have to be started again Illustration 3 A handy text output console can be show and hidden When the program begins it is hidden 3 4 Help Menu To view information about the development of this software or to link quickly to this user manual options have been made available in the Help menu In this menu you will first see the About menu which will display a pop up window with information about the development of this program To have quick access to this manual the second option of the Help menu comes in quite handy Click on Manual and the document will automatically be loaded for viewing in your computer s preferred applications for PDF documents 4 Beginning a Verification There are two possible verification types that can be carried out The differences between the two are primarily thoroughness The Universal Verification option will evaluate every applicable
14. sort the result by entity In addition a VerificationResult can contain a report which is an object that contains additional information about a VerificationResult The following cases are possible e The result in the VerificationResult is false e An exception has occurred during computation e The cryptographic check is not implemented We want to add some additional information about a verification We can use a report to print additional information about a certain check for example we use it to explain which plausibility tests are performed in some NIZKP 3 9 ElectionBoardProxy Each verification process queries this class for election data The concept behind an ElectionBoardProxy is that each verification will have only one object of this type so that we can cache the downloaded results for the started verification process This will speed up the verification procedure We can see how we to construct an ElectionBoardProxy public ElectionBoardProxy String eID VoteVerifier Independent Verifier for UniVote Elections 2 this eID eID this wsdlURL new URL Config wsdlLocation getElectionBoard First of all we have to provide an election ID This is because the public board of UniVote needs it in order to send the relative data The communication between the public board and our software is done through web services From the constructor above we can see the getElectionBoard method by which we initialize
15. A A n eens e eaaa e an ae a aie 31 VoteVerifier Independent Verifier for UniVote Elections LP e OTC Een EE 35 4 1 Remaining Tasks to Complete ek 35 4 2 Acquired Knowledge sise 35 Use Cases mine een 37 User Malal iia tr et e A me en te 43 VoteVerifier Independent Verifier for UniVote Elections VI Basement o List of Illustrations Illustration 1 1 The flow of the information from generation to VoteVerifier results 2 Illustration 1 2 Planning of the development of the project see eee 5 Illustration 1 3 The results of the verification process are shown in a table 7 Illustration 2 1 Sections of the graphical user interface 15 Illustration 3 1 Example of a quick response code 20 Illustration 3 2 VoteVerifier class diagram eee eee 21 Illustration 3 3 VoteVerifier system Sequence diagram eee eee 22 VoteVerifier Independent Verifier for UniVote Elections VI Basement o Contents of the Tables Table 1 Planning of the development ss 6 Table 2 Cryptographic checks that VoteVerifier performs 10 Table 3 How the verification result and additional information are interpreted 16 Table 4 Explanation of unsuccessful tests 32 VoteVerifier Independent Verifier for UniVote Elections VI 1 Introduction The Internet plays an ever greater role in an even increasing number of aspects of life Practically all areas
16. Check if getEncryptedVotes and getEncryptedVotesMixed By are correct ParamImpITest testVotes Here we have a problem with the computation of a value m We have seen that our computations give back a m too big as the expected one Bug in our code or problem with the order of the set given by getPartiallyDecryptedv otes RSAImpITest testSingleBallot Here we don t know how concatenate the RSA signature contained in a QR Code Concatenation of the string used to compute the signature RSAlmplTest testBasicParam Failure in the verification of the signature Same as above RSAImpITest testLatelyRegisteredVotersK eysBySign Same as above Same as above RSAImpITest testMixedVerificationKeysBy Sign Same as above Same as above RSAImpITest testShuffledEncVotesSign Same as above Same as above RSAlmplTest testElectionData Same as above Same as above RSAlmplTest testElectoralRoll Same as above Same as above RSAlmplTest testElectionOptions Same as above Same as above RSAImpITest testMixedEncVotesBySign Same as above Same as above RSAImpITest testPlaintextVotesSign Same as above Same as above VoteVerifier Independent Verifier for UniVote Elections RSAImpITest testLatelyRegisteredVotersK eysSign We did not find the signature RSAImpITest testLatelyRegisteredVotersC ertSign Same as
17. Ds will pop up and you will be able to select a new election ID from this list After clicking on one of the possibilities your selection will now be displayed in the text box and you are now ready to begin the verification process by clicking on the blue Start button Illustration 4 The election IDs can be selected out of a provided list or inputed manually Clicking start causes a new tab to appear and its content will be immediately displayed The verification results begin to appear and the status of the verification process is displayed More about this verification tab can be found in the section entitled Viewing Results 4 2 Individual Verification The individual verification process is comparably much faster than universal verification In this Please select a verification type and click start verification the certificates signatures mathematical proof and if the ballot was included in the Verify the contents of a single ballot election results The entire process Please select a file that contains a QR Code lasts less than a few seconds Universal Verification Individual Verification Start select To begin an individual verification change the selected verification type to individual verification by clicking on the button The setup choices under your selection will change to display instructions for selecting a Illustration 5 Execute an individual verification by selection an file which contains an elec
18. E ee da anas 7 2 System Description EE 8 Sch Cryptography sn ram enter eege Eegen ue Eege dee 8 KEN Ta WEIEN 8 2127 ENG ata sare ES be ES Ee 8 S D A TT 8 2 1 4 Non Interactive Zero Knowledge Proof 9 2 1 5 Certificates iii ad 9 2 2 UniVot s Voting Se E E T E ruser 9 2 3 List of Le le EE 10 2 4 Graphical User Interface 14 24 1 Interpreting Results sus 16 2 42 Helper R ent id M VA RARE NS 16 24 3 View Modimcaionsg sss sees 17 2 4 4 Passing Messages to the GUL 17 A Technical Implementation eee eee eee eee eee 19 311 Technology TT 19 3 1 1 Programming Language 19 REN EE 19 K E WED SERVICES EE E E E en e a ts 19 c EE 19 321 5 tte EE EE E 20 A e EE 20 32 Class DIA AM da 20 3 3 System Sequence Diagram nn Na aaia ya aiia PN Naaa 22 3 4 Tie lt T 27 iiia iranienne iiaa aaiae iat aaien aiani 23 3 4 1 Certificates Implementer rnn nnnnneeenn eee 23 3 4 2 RSA Implementer ss 24 3 4 3 Schnorr Implementer renee 24 3 4 4 Parameters Implementer ENEE 25 3 4 5 Proof lmplementens 6 240222 2238205 mains Nat pet I eise 25 3 5 A ie engined de Gut Pa La Prada area lerede drer ECH 26 R E e SR RE nes Se A Re ne ss tin 27 3 7 Thread Manager insert Me Sere ieee M Me eee i EE 28 3 8 Verification Result 29 3 9 leCtlonBoardPrOX cocido 29 3 10 Customization of Messages nci oe Bi AN be aada Rebel he a 31 IMA JUNIE Test ci A A A E 31 K h E
19. Object r sc pushRightDelim String concat sc pullAll BigInteger hashResult CryptoFunc sha256 concat mod q return hashResult equals a The input for the method is the verification key used to verify the signature the message the two values of the Schnorr signature and the generator for which we want to compute the r values First it computes r g vk mod p which is the value that is concatenated to the message and the sha 256 mod q hash will be computed If this value corresponds to the a value then the signature is verified GCHECK VoteVerifier Independent Verifier for UniVote Elections 24 3 4 4 Parameters Implementer This implementer called Parametersimplementer is used to compute different values and it is not specific to a particular domain as is for example the RSAlmplementer for RSA signatures Here we can find different methods and we can briefly list the purpose of them 1 Verification of prime numbers and safe primes 2 Correctness of the length of the encryption parameters p q and g for Schnorr and ElGamal 3 Validity of the ballots 4 Verification of the last set of data for the last mixer Here we have an example where we check if a ballot belongs to the set of all ballots public VerificationResult vrfBallotInSet BigInteger verificationKey Exception exc null boolean r false Report rep Ballot qrCodeBallot ebp getBallot verificationKey check if the ballot belo
20. Voter Success Guarantee The choices for beginning an individual verification for a given election receipt are shown Main Success Scenario 1 The user starts the program or clicks on the Welcome tab VoteVerifier Independent Verifier for UniVote Elections 3 2 The user clicks on the radio button Individual Verfication 3 Directions for the following step and a button to allow file selection are shown in the welcome tab Use Case 7 Use Case UC7 Select an Election to Verify Primary Actor Voter Success Guarantee The selected election ID appears in the combo box and will be used in the universal verification Main Success Scenario 1 The user starts the program or clicks on the Welcome tab 2 The user clicks on the combo box containing possible election IDs which can be used in a universal verification 3 The selected election ID is showing in the combo box and will be used when the user clicks start Use Case 8 Use Case UC8 Select a File to Verify Primary Actor Voter Success Guarantee The path for the selected file is saved in a variable and shown to the user Main Success Scenario 1 The user starts the program or clicks on the Welcome tab 2 The user clicks on the radio button individual verification 3 The user clicks on the select button 4 pop up file chooser window appears 5 The user selects a file and clicks ok 6 The path to the selected file i
21. a safe prime Signature of EA certificate Signature of election s basic parameters VoteVerifier Independent Verifier for UniVote Elections 2 System Description This paragraph explains how the system works in a non technical way In particular we will show what cryptographic primitives are involved in our project and we will also see how the voting process of UniVote works 2 1 Cryptography Our thesis is strong related to some cryptographic primitives used by UniVote These permit to the election system to work correctly These permit to have a secure e voting platform and more in particular they guarantee the integrity and the secrecy of the voting data as well the anonymity We now describe each cryptographic component 2 1 1 RSA Signatures RSA is mainly an asymmetric public key algorithm used to encrypt and decrypt the data we want A party who wants to send a message to one other must first get the public key of the other so that he can compute the encrypted message Then the receiver can decrypt the message using the private key RSA can also be used as a signature scheme so that it s possible to verify the integrity of data If a party wants to generate a signature in order to give the possibility to verify the integrity of some data it must first hash the data with a given hash function and then compute the signature with its private key A possible verifier must first get and hash with the same hash function the da
22. above RSAImpITest testLateRenewalOfRegSignB y Data for this proof were not available RSAImpITest testEACertld We did not find the signature RSAlmplTest testTMCert Same as above RSAlmplTest test VoterCertiD We don t know how to concatenate the certificate CertimplTest testLatelyVotersCerts This check fails because of this basic constraints check failed this is not a CA certificate This is caused by a missing extension in the CA certificate Add to the extension field of the CA certificate the relative value CertlmplTest testVotersCert Same as above Same as above ProoflmplTest testLateRenewalOfRegistrat ionProofBy Data for this proof were not available ProoflmpITest testBallotProofFromBallot The proof fails since v w The concatenation can be a possible problem ProoflmplTest testBallotProofFromQRcode The proof fails since v w The concatenation can be a possible problem SchnorrlmpITest testSignatureVerificationF romBallot We were not able to verify a Schnorr signature even if the computations seem to be correct The concatenation of the value for the hash inside the vrfSchnorrSign can be the problem SchnorrlmpITest testSignatureVerificationF romQRCode Same as above Same as above ElectionPreparationRunnerTest testResult List These test fails because not all methods return true as verificati
23. ager of killThread processID with the given process ID which uniquely identifies the running verification process If the thread is active it will be VoteVerifier Independent Verifier for UniVote Elections 28 interrupted and removed from the list of threads that the Thread Manager maintains If the thread was no longer running then no action is taken 3 8 Verification Result A VerificationResult is created by a method of an Implementer These objects are mainly used to store information about the state of the cryptographic check We can illustrate an example of a VerificationResult created by the vrfriGamalParamSing of the RSAlmplementer new VerificationResult VerificationType EL SETUP ELGAMAL PARAMS SIGN result ebp getElectionID RunnerName ELECTION SETUP ImplementerType RSA EntityType EM The parameters are explained here e VerificationType EL SETUP ELGAMAL PARAMS SIGN the type of cryptographic check result usually a boolean value indicating the success or failure of this check Ebp getElectionID the ID of the election for this check RunnerName ELECTION SETUP the name of the runner which has requested the check This field is used to sort the results by Runner ImplementerType Rsa the type of implementer that has performed the check This field is used to sort the results by Implementer EntityType Em the UniVote entity that has verified the data of this check This field is used to
24. al election displays the election ID of the results it contains If the results are for an individual election the tab shows the prefix Ind followed by the election ID Clicking on a tab will show the results for that election verification process Clicking on the Welcome tab will allow you to begin a new election verification process VI O Lt j D EP E M DLE Weritie VERIFIER ywote Welcome Ind vsbfh 2013 x Pvsuzh 2013 S Entity Type Election Results Specificatio 17 Errors and Exceptions Illustration 6 The different verification processes are organized into tabs with the corresponding name of the election ID Each tab is organized into three parts At the top there is a view panel which shows choices to view the results organized in a different way or to view the results of the election which shows how many votes the parties and candidates received After the button panel comes a text area in which Errors and Exceptions will be displayed And finally there is the main results panel in which the verification results are displayed Each component of the tab is discussed in detail in the rest of this section 5 2 Organizing Verification Results When the verification tab appears that default organization for the results is set to specification This means that the results are ordered according to how they are listed in the system specification of the UniVote electronic voting system S
25. as hidden and hidden if it was already shown Use Case 3 Use Case UC3 Changing the language Primary Actor Voter Success Guarantee The main window will be rebuilt and set to the initial state with the newly chosen language Main Success Scenario 1 The user clicks on Language option in the menu bar 2 The user scrolls down to the desired language option and clicks on it VoteVerifier Independent Verifier for UniVote Elections 38 3 The console window is rebuilt with the text in the language selected Use Case 4 Use Case UC4 View the about screen Primary Actor Voter Success Guarantee The information about the project will be shown in a pop up window Main Success Scenario 1 The user clicks on Help option in the menu bar 2 The user scrolls down to the About option and clicks on it 3 A pop up window appears with the information about the software Setup Use Case 5 Use Case UCS Select Universal Verification Primary Actor Voter Success Guarantee The choices for beginning an universal verification for a given election ID are shown Main Success Scenario 1 The user starts the program or clicks on the Welcome tab 2 The user clicks on the radio button Universal Verfication 3 Directions for the following step and a comboBox with possible election IDs are shown in the welcome tab Use Case 6 Use Case UC6 Select Individual Verification Primary Actor
26. ated this method must be called to start the whole process It iterates over the list of runners for which it executes run each time The list of all the result returned is primarily used for JUnit testing This is an extract Of runVerification createRunners run the runners and get the results for Runner r runners the result runner doesn t support run but runResult if r instanceof ResultsRunner ResultsRunner rr ResultsRunner r rr runResults else List lt VerificationResult gt 1 r run return Collections unmodifiableList res 3 7 Thread Manager It is necessary to start the verification processes in their own thread due to the intensive calculations that they carry out If this were not the case the demands placed on the CPU would block Event Dispatcher Thread of the graphical user interface and actions performed by the user would hang When a thread is created by the StartAction it is registered with the ThreadManager which exists as a single instance for the entire program The task of the ThreadManager is to reply if a given thread exists to interrupt a given thread or to interrupt all threads that are running These features come into play in two cases If a verification result window is closed while the verification process is still running then it is necessary to signal to the verification process that all further activity should cease In this case a Call is made to the ThreadMan
27. can pass what they want as arguments VoteVerifier Independent Verifier for UniVote Elections 22 3 4 2 RSA Implementer This class called RSAlmplementer does example as the name implies and that is to verify RSA signatures The method that provides the verification of a signature as follows public boolean vrfRSASign RSAPublicKey pubKey String clearText BigInteger signature BigInteger hash CryptoFunc sha256 clearText BigInteger decSign signature modPow pubKey getPublicExponent pubKey getModulus boolean result decSign equals hash return result As input it takes the public key to verify the signature the message to be verified and the signature itself The public key of RSA is composed of two values the exponent e and the modulus n so to verify a signature it computes signature mod n Then if this value corresponds to the sha 256 hash of the message the signature is correctly verified All the other methods of this implementer wrap vrfrsasion and pass the relative values 3 4 3 Schnorr Implementer The implementer class called Schnorrlmplementer verifies a Schnorr signature The method is public boolean vrfSchnorrSign BigInteger verificationKey String message BigInteger a BigInteger b BigInteger gen BigInteger r gen modPow b p multiply verificationKey modPow a p mod p sc pushLeftDelim sc pushObjectDelimiter message StringConcatenator INNER DELIMITER sc push
28. control system we have chosen Git so that we are able to manage the changes of the code between the project members Git permits the consultation of the source code online and our project is hosted at https github com EVGStudents VoteVerifier git VoteVerifier Independent Verifier for UniVote Elections 3 1 5 XStream This is a library we used to store the data from an election to XML files so we can use them to perform JUnit testing without having the need to use the network 3 1 6 ZXing ZXing pronounced Zebra Crossing is an open source library implemented in Java and developed by Google The library provides handling of 1D and 2D barcodes In the VoteVerifier software it was necessary to decode the information contained in a special kinds of 2D barcode called a Quick Response Code or QR Code A QR Code is square shaped grid like image in which certain cells of the grid a black An example of QR Code which represents the data contained in an election receipt can be seen in the figure below Illustration 3 1 Example of a quick response code 3 2 Class Diagram We can now explain the structure of our program This section explains the main organization of the classes in the program First we have a look at the class diagram VoteVerifier Independent Verifier for UniVote Elections 2C Illustration 3 2 VoteVerifier class diagram starts SZ IndividualVerification elD String runVerificati
29. d the verification results and get additional help The complete user manual is displayed on the following pages VoteVerifier Independent Verifier for UniVote Elections O e rif ie User Manual C Contents 1 Introduction 2 Overview 3 Menu and Options 3 1 File Menu 3 2 View Menu 3 3 Language Menu 3 4 Help Menu 4 Beginning a Verification 4 1 Universal Verification 4 2 Individual Verification 4 3 Additional Verification Processes 5 Viewing Results 5 1 Tabs 5 2 Organizing Verification Results 5 3 Interpreting Results 5 4 Helper Text 5 5 Candidate Results 5 6 Errors and Exceptions 6 Thanks 1 Introduction Welcome to VoteVerifier the independent verifier for elections held with the UniVote electronic voting system This system was designed to boost confidence in the UniVote system by verifying the election results of a given election or election receipt You should already have general knowledge of the UniVote system but you can also find more information at www UniVote ch 000 nn __UniVerifier 2 File View Language Help Overview V RE INDEPENDENT MH erifier VERIFIER SS vote This manual will guide you through the basic features and operations of the VoteVerifier program Upon loading you will see the main welcome window and menu bar at the top You will be guided through use of the program Universal Verification O Individual Verification Start beginning with periphery operations follo
30. data from the election board For this reason there is only one actor who fills the primary role in the use cases User Primar The user who starts a desired y verification process List of Use Cases Menu Bar Functionality 1 Exit the program 2 Console View Selection 3 Language Choice 4 View the About screen Setup gn Select Universal Verification Select Individual Verification Select an Election to Verify Select a File Select Start Oro N After Verification Started 10 Return to Welcome Screen 11 Close a Tab 12 Sort Election Verification Results 13 View Candidate Election Results VoteVerifier Independent Verifier for UniVote Elections 37 Use Cases in Fully Dressed Format Menu Bar Functionality Use Case 1 Use Case UC1 User exits the program Primary Actor Voter Success Guarantee The program will close and shutdown Main Success Scenario 1 The user clicks on File option in the menu bar 2 The user scrolls down to the Exit option and clicks on it 3 The main program window will disappear and Use Case 2 Use Case UC2 Toggling visibility of console Primary Actor Voter Success Guarantee The console will be shown or hidden at the bottom of the program window Main Success Scenario 1 The user clicks on View option in the menu bar 2 The user scrolls down to the Show Console option and clicks on it 3 The console window will be shown if it w
31. e00 o Bern University of Applied Sciences b Engineering and Information Technology Bachelor Thesis 2013 VoteVerifier Independent Verifier for UniVote Elections Division Computer Science Students Giuseppe Scalzi Justin Springer Professors Dr Eric Dubuis Dr Rolf Haenni Expert Han van der Kleij VoteVerifier Independent Verifier for UniVote Elections Berner Fachhochschule eooo Haute cole sp cialis e bernoise e Technik und Informatik Technique et informatique Abteilung Informatik Division informatique Erkl rung der Diplomandinnen und Diplomanden D claration des dipl m e s Selbst ndige Arbeit Travail autonome ich best tige mit meiner Unterschrift dass ich meine Bachelor Thesis selbst ndig durchgef hrt habe Alle Informationsquellen Fachliteratur Besprechungen mit Fachleuten usw die wesentlich zu meiner Arbeit beigetragen haben sind in meinem Arbeitsbericht im Anhang vollst ndig aufgef hrt Par ma signature je confirme avoir effectu mon m moire de Bachelor de mani re autonome Toutes les sources d information litt rature sp cialis e discussions avec sp cialistes etc qui m ont fortement aid es dans mon travail sont int gralement mentionn es dans l annexe de mon m moire Name Nom Vomame Pr nom Div Gei 5 Jus H AA Datum Date lad 2043 Unterschrift Signature Dieses Formular ist dem Bachelor Thesis Bericht beizulegen Ce formulaire doit tre joint au rappo
32. ection results which entails the votes that each political party and candidate received VoteVerifier Independent Verifier for UniVote Elections Help The program should offer two methods of receiving help There should be a user manual available that can be accessed from within the program Additionally information should be supplied about why a verification result failed by clicking on or hovering over the verification result Installer The software can be installed using an installer and is available as a digital download and will support the three main computing platforms Windows Mac OSX and Linux As agreed upon the software installer will be created and added to the project by Dr Dubuis Internationalization The program will be available in three languages English German and French 1 5 Project Planning For our planning we have chosen to divide the different phases into iterations so that we can have a better control over the development cycle We can explain the different tasks with the following table VoteVerifier Independent Verifier for UniVote Elections Illustration 1 2 Planning of the development of the project SUL ct documentation planning milestone 1 iteration 1 crypto primitives milestone_2 iteration_2 communication with EB milestone_3 iteration_3 GUI and code integration milestone_4 release milestone_5 13 March 2013 April 2013 May 2013 une 2013
33. er 160 SETUP_CA_CERT CertificatesImplementer 200 EL_SETUP_EA_CERT CertificatesImplementer 210 EL_SETUP_BASICS_PARAMS SIGN 1 3 4 b RSAImplementer 215 EL SETUP TALLIERS CERT 1 3 4 b CertificatesImplementer 220 EL_SETUP_MIXERS_CERT 1 3 4b CertificatesImplementer 225 EL_SETUP_T_CERT_M_CERT_ID_SIGN 1 3 4b RSAlmplementer 230 EL SETUP ELGAMAL P ParametersImplementer 231 EL_SETUP_ELGAMAL_Q Parametersimplementer 232 EL SETUP ELGAMAL G Parametersimplementer 233 EL SETUP ELGAMAL SAFE PRIME ParametersImplementer 234 EL_SETUP_ELGAMAL_PARAM_LEN Parametersimplementer 235 EL SETUP ELGAMAL PARAMS SIGN RSAlmplementer EL SETUP T NIZKP OF X 1 3 4d Prooflmplementer 245 EL_SETUP_T_NIZKP_OF_X_SIGN 1 3 4d RSAlmplementer EL SETUP T PUBLIC KEY 1 3 4d Parametersimplementer Parameters Parametersimplementer VoteVerifier Independent Verifier for UniVote Elections 11 255 EL SETUP T PUBLIC KEY SIGN 1 3 4 d EM RSAlmplementer 260 EL SETUP M NIZKP_OF ALPHA Prooflmplementer 265 EL SETUP M NIZKP OF ALPHA SIGN RSAlmplementer 270 EL SETUP ANON GEN ParametersImplementer 300 EL_PREP_C_AND_R SIGN RSA I blemerter 310 EL _PREP_EDATA SIGN 1 3 5 b RSAlmplementer 320 EL_PREP_ELECTORAL_ROLL_SIGN RSAlmplementer 330 EL_PREP_VOTERS_CERT CertificatesImplementer 350 EL_PREP_M_PUB_VER_KEYS 1 3 5d Prooflmplementer 360 TEL PREP M PUB VER KEYS SIGN 01 03 05 RSAImplementer 370 EL PREP PUB VER KEYS 1 3
34. have not tested them using data that we know to be false For example we could use an invalid QR Code with fake data This can be done in the future in order to test that our computation really works 3 11 1 Test Failures Although we strictly followed the specification of UniVote there are still some problems The possible nature of these problems can be identified in the actual implementation of UniVote or in a bug in our code For the first reason we can find some discrepancies between the implementation and the specification that can cause an error during the verification process of some cryptographic data We cannot however exclude the possibility of a bug in our code and for this reason there will be the need to modify the actual code in order to fix problems or to adapt what we have written to a possible new version of UniVote The tests have been executed with the data of risis 2013 1 and of vsbfh 2013 The tests involving a QR Code involve only the election ID vsbfh 2013 since we have a QR code from only that election We can now group here the tests that are not successful and give a possible explanation VoteVerifier Independent Verifier for UniVote Elections 31 Table 4 Explanation of unsuccessful tests Test Comments Possible cause ParamimpiTest testMixedExncryptedVotes This test fails because the set of encrypted vote is not equal to the set of encrypted vote of the last mixer
35. is possible to modify the output messages We have three properties files e messages properties prints the title of a cryptographic check o i e 160 CA certificate e failurecode properties contains failure messages o i e if an RSA signature is invalid The format of messages properties and addinfo properties is the same There is a key which is a number and the value which is the text The key is the ID of a cryptographic check These IDs can be found in the enumeration VerificationType located in the common package The format of failurecode properties is the same except that the key does not correspond to a certain cryptographic check This is because the same failure can occur for different cases 3 11 JUnit Tests Basically we tried to follow a logic in our testing and we first test each cryptographic check that we can find in the Implementer classes and then we test if each Runner performs the various call to the Implementer in the right order Finally we test a Verification by checking for example the size of the result list and the results Other tests check QR Code processing string concatenation and hashing functions We have chosen not to establish a network connection during testing and so data from the public board has been stored locally for running the tests We have used the class LocalBoardProxyDownloader to download the data We test our methods with data that is assumed to be valid but due to time constraints we
36. length e Prooflmplementer for the verification of NIZKP Each method in an Implementer also produces a VerificationResult which is an object that contains all the necessary information about the outcome of a particular check We want to briefly give an example of each Implementer in order to give a better idea of what they do 3 4 1 Certificates Implementer The Implementer Class called CertificatesImplementer is dedicated to the verification of X509 certificates which can belong to the different entities involved in UniVote We can see the main method used to verify a certificate public boolean vrfCert List lt x509Certificate gt certList CertificateFactory cf CertificateFactory getInstance X 509 CertPath cp cf generateCertPath certList TrustAnchor anchor new TrustAnchor certList get certList size 1 null PKIXParameters params new PKIXParameters Collections singleton anchor params setRevocationEnabled false CertPathValidator cpv CertPathValidator getInstance PKIX cpv validate cp params return true This method validates a certificate chain composed by one ore more certificates by using the certificate path validator algorithm provided by Java The methods in this class can wrap vrfCert in order to verify a certificate and this is the basic idea that we tried to follow in the other Implementers The idea is to have a general method that can be wrapped by other method that
37. lustrates the criteria upon which the algorithm acts to choose appropriate results and additional information to show Table 3 How the verification result and additional information are interpreted Implemented Not implemented No additional text Failure code text Failure code text x Failure code text A True Y False x Exception A Exception Exception 2 4 2 Helper Text If a verification was not successful additional information about what went wrong may be obtained by clicking on or placing the mouse over the verification will cause a small blue helper text to appear providing a brief explanation of why the verification was not a success In the table above for example the results of a successful verification are shown with a green check If the verification has not been implemented then the icon will be an orange question mark and the failure code text will be shown in the pop up helper text in the table containing the verification results If the result is false the icon is always a red x and the failure code will VoteVerifier Independent Verifier for UniVote Elections again be shown in the helper text Lastly if an exception occurred then this exception will appear in the helper text With this mechanism the user can get more information about what the results mean and how serious of a situation it is if a certain verification has not succeeded The descriptions in the helper text however are
38. m will be able to execute a verification of an entire election called a universal verification as well as an individual verification to verify a single election receipt The two verifications are briefly discussed below In a universal verification the system parameters signatures certificates and non interactive zero knowledge proofs NIZKP are verified To begin a universal verification an election ID must be provided to allow the program to fetch the information to verify The program displays the output of the verification process in a table An individual verification verifies a certificate signature and NIZKP and if the ballot was included in the election results The input for this verification is a quick response code QR code which contains the information of an election receipt The entire process lasts less than a few seconds and again the results are displayed in a table Information about the cryptography involved in these verifications can be found in the section entitled Cryptography Reading QR Code After voting in an election using the UniVote system the user is given an electronic receipt which contains the election ID encryption of the users vote signatures timestamp and other information Multiple Views of Results The program should offer three different views of the results The views are according to system specification election entity and result type Additionally there must be a section to view the el
39. me Config q VerificationType SETUP SCHNORR 01 msgr sendVrfMsg v2 partialResults add v2 Thread sleep SLEEP TIME verifiy EM certificate VerificationResult v7 certImpl vrfEMCertificate msgr sendVrfMsg v7 partialResults add v7 return Collections unmodifiableList partialResults When the run method of this Runner is called we see that some checks of prime numbers will be performed as well as a check of a certificate We also see that it sends the result to the GUI through the messenger msgr variable The list of results that this method returns is mainly used for testing purposes Each of these runners corresponds to a phase of an election according to the UniVote specification 3 6 Verification This class represents a Verification and it is the key point of the infrastructure From here the whole verification process starts for both the universal and individual verification VoteVerifier Independent Verifier for UniVote Elections 21 This super class is responsible for creating the instance of the ElectionBoardProxy so that each verification has its own data Each verification can be identified by an election ID A Verification is also responsible for the creation of the necessary runners A specialized class of this kind must override the createrunners method in order to delegate a certain number of Runners The runverification method is the most important because if a verification is cre
40. ming messages by their process ID there were two options Either the verification Runner classes would need to know for which process they were working for or the Messenger over which the Runner communicated with the GUI would know to which process ID they belonged The Messenger Manager allows multiple instances of the Messenger class to be organized and distributed to the appropriate verification threads Before a thread is created the Start Action contacts the Messenger Manager and asks for an instance of a Messenger for a given Process ID The Messenger Manager maintains a single reference to the Listener subclass in the Main GUI and registers this reference with each new Messenger class that it creates This Messenger instance is then passed on to the thread for the verification process In this way there is only one point of entry for messages to arrive in the GUI but the messages a differentiated by process ID without bogging down the Runner classes with this information VoteVerifier Independent Verifier for UniVote Elections A Technical Implementation This section will explain in detail how the verification software works Certain aspects such as the organization behind a verification or the technology used will be analyzed and described 3 1 Technology This paragraph explains the technology we have used from the coding language to the various tools and libraries that are present in our software 3 1 1 Programming Language
41. n the middle both of which are visible by default upon starting up the program and the console panel at the bottom which contains text relevant to the verification process being run The first section is the title panel which contains the logo and description of the program Below the title panel is the main content panel or middle panel which constitutes the bulk of the graphical user interface and contains the interface required to begin verifying an election check verification results and view the votes the various parties and candidates received The third panel is hidden by default but can be viewed by toggling the visibility in the view menu The panel contains a console in which the results of the verifications are output in as text When multiple verifications have been initiated then there is a console window that corresponds to each verification process that has been created Switching between these verifications switches automatically the text of the console VoteVerifier Independent Verifier for UniVote Elections eoo File View Language ENE Please select a verification type and click start Universal Verification Individual Verification Start Verify the results of an entire election sub 2013 L Welcome to VoteVerifier Please select a verification type and click start The class organization of the components of the user interface reflects the visual layout The main window is cons
42. nd accuracy of the system can be shown to be trustworthy But who can check these proofs Should blind trust be placed on the UniVote team to have honestly and diligently implemented the checks and proofs Whose word shall we trust to say that the results of an election are valid To meet these demanding needs in the e voting community the VoteVerifier verification software validates the parameters proofs adherence to the system specification as well as the results of elections held with the UniVote e voting system The VoteVerifier software provides participants in the elections of Swiss universities an extra boost of confidence in the integrity of the university student governmental system 1 1 Purpose The VoteVerifier project was created to provide an independent verification software to confirm the results from elections held with a specific e voting software platform called UniVote The developers of this project are students majoring in IT Security and chose this project to deepen their knowledge of cryptography IT security software development and e voting systems This project serves as a Bachelor s Thesis for the Bern University of Applied Sciences in Biel and was carried out from February to July 2013 under the supervision of Dr Dubuis and Dr Haenni 1 2 Theme UniVote is an e voting system developed by the Bern University of Applied Sciences in Biel UniVote is the result of many years of research activity at the Bern University
43. ng and tallying during this last phase the encrypted votes will be mixed and the vote will be decrypted in order to get the final result Our software must go through all the phases except the registration phase download and verify the data published during each of them For a detailed explanation of the UniVote protocol please consult the specification on the project page http e voting bfh ch projects univote 2 3 List of verifications Here we want to list all the cryptographic checks that we must to perform Each of the 60 checks belong to a precise voting phase defined in the UniVote specification This table contains all of them and in the first column we can find the code that identifies a particular check in our software along with the description in the second column The Specification paragraph column tells us where this check is defined in the specification The Entity column explains which entity listed in the previous section is responsible for verifying this check The last column simply tells in which class this check is located Table 2 Cryptographic checks that VoteVerifier performs paragraph SETUP SCHNORR P ParametersImplementer SETUP_SCHNORR_Q Parametersimplementer SETUP SCHNORR P SAFE PRIME ParametersImplementer VoteVerifier Independent Verifier for UniVote Elections 130 SETUP SCHNORR G 1 3 1 140 SETUP_SCHNORR_PARAM_LEN ParametersImplementer 150 SETUP_EM_CERT CertificatesImplement
44. ngs to the set of all ballots for Ballot b ebp getBallots getBallot if qrCodeBallot equals b r true break VerificationResult v new VerificationResult VerificationType SINGLE BALLOT IN BALLOTS r ebp getElectionID rn it EntityType PARAMETER return v 3 4 5 Proof Implementer This last implementer which is called Prooflmplementer is used to perform the verification of the NIZKP There are mainly two types of proofs to verify the proof of knowledge of discrete log and the equality of discrete log We want to give as example the proof of knowledge of discrete log because they are used most frequently VoteVerifier Independent Verifier for UniVote Elections 26 public boolean knowledgeOfDiscreteLog BigInteger t BigInteger s BigInteger c BigInteger paramV BigInteger paramW BigInteger prime boolean vExponentSign if vExponentSign S s negate BigInteger v paramV modPow s prime BigInteger w t multiply paramW modPow c prime mod prime return v equals w This method which verifies the knowledge of discrete log takes the following information as parameters see the specification of UniVote for additional information about NIZKP paragraph 1 1 4 and 1 4 1 for a practical example 1 t the commit value of a proof 2 S the response value of a proof 3 c the hash of the some precomuted values 4 paramV the parameter used in the computation of the
45. not incredibly detailed and require a certain level of technical knowledge In upcoming versions of this software it would be recommended to introduce descriptions that are also more useful for the layperson 2 4 3 View Modifications The view of the program will change based on the system that the program is running on The program will identify the operating system upon which it is running and select an appropriate look and feel for the graphical components such as buttons menu bars and scroll bars Additionally the user may choose to show or hide a console like text area in which messages will be displayed This text area is by default hidden but will appear at the bottom of the screen upon request To show the text area the user will click on the view menu and then check or uncheck the show console option 2 4 4 Passing Messages to the GUI This software respects the convention of the separation of the programming of the GUI from the implementation of rest of the code This architecture is achieved through the use of the listener pattern in which the GUI registers a listener object implemented as an inner class with a subject object also an inner class contained within a class of the main code In this program the subject inner class has been implemented in a class called Messenger which is solely dedicated to sending messages to the GUI or to the console in the case of running the program from the terminal Initially it was de
46. on List lt VerificationResults gt 1 ElectionBoardProxy elD String wsdlURL URL UniversalVerification runs ebproxy ElectionBoardProxy elD String name RunnerName run List lt VerificationResult gt SystemSetupRunner ElectionSetupRunner Parametersimplementer vrfPrimeNumber p VerificationResult a vrfGenerator g VerificationResult Implementer vrfSafePrime p VerificationResult Implementer vrfParamLen VerificationResult ebproxy ElectionBrdProxy name RunnerName Certificatelmplementer vrfCert cert pubKey boolean vrfEACert VerificationResult We mainly have three super classes a Verification a Runner and an Implementer We can create the specialized version of each class in order to fit our needs For example we can see from the diagram that we have two kinds of verifications individual and universal The idea is to divide the whole verification process into small pieces called Runners which ask an Implementer to compute some cryptographic checks VoteVerifier Independent Verifier for UniVote Elections 21 3 3 System Sequence Diagram Before introducing the classes we can illustrate the sequence diagram of a verification Illustration 3 3 VoteVerifier system sequence diagram new elD new elD runVerification vrfPrimeNumber p VerificationResult vrfElectionDefinitionSign Verifica
47. on result It will work when there will be no problems anymore VoteVerifier Independent Verifier for UniVote Elections aerer o ElectionPeriodRunnerTest testResultList Same as above Same as above IndividualRunnerTest testResultList Same as above Same as above ElectionSetupRunnerTest testResultList Same as above Same as above MixerTallierRunnerTest testResultList Same as above Same as above Please note that this list can change with the election ID In fact the data for the risis 2013 1 election are the most recent so they have been computed after some bug fixing Those bugs were still present during the vsbfh 2013 and sub 2013 elections VoteVerifier Independent Verifier for UniVote Elections 4 Conclusion The goal of this project was to provide a simple utility that independently evaluates the trustworthiness of the UniVote e voting system This software achieves its goal of simplicity and ease of usability as well as the independent nature That it provides a boost of confidence in the veracity and accuracy of the UniVote e voting system is however debatable Unfortunately quite of few of the verifications fail and without an in depth expert knowledge of the system and its specifications the results of this verification software could be misleading 4 1 Remaining Tasks to Complete In large part all of the tasks of this project were completed to a satisfactory level
48. onic elections We hope that you feel more assured in the discretion veracity and exactitude of the UniVote system and that you will continue to use this software in the future For questions and comments please visit the UniVote website at www UniVote ch and contact one of the members of the UniVote team
49. ons from the student body elections of the University of Bern the University of Zurich and the Bern University of Applied Sciences should be used VoteVerifier Independent Verifier for UniVote Elections In the development of the program the highest possible level of independence from and impartiality to the UniVote system and team should be maintained In order to guarantee the impartiality of the verification software the source code from the UniVote system may not be used in development of this verification software That being said without cooperation with and instruction from the UniVote team this project would not have been possible 1 4 Requirements This section discusses the requirement that the software is to meet Detailed explanations of the functionality architecture and more can be found in the sections system description and technical implementation Adherence to the UniVote Specification The software should be developed in strict adherence to the specification document for the UniVote system The alternative would be to create the verification software in manner that the UniVote system was actually built As a consequence deviations from the specification by the UniVote team result in a verification result other than true It was agreed upon during development that the deviations were the responsibility of the UniVote team to address and not that of the development team for VoteVerifier Two Verification Types The progra
50. parameter of the election system of a given election ID whereas the individual verification verifies comparably much less 4 1 Universal Verification The length of a typical verification process using the Universal Verification is approximately 2 to 10 minutes depending on the processing power of the computer In this verification all certificates signatures mathematical proofs are verified and displayed for the user When the program begins you are all set to begin the universal verification which is already selected by default If an active internet connection was detected and a connection was successfully established with the election board a list of possible election IDs will be displayed in the text box in the middle of the screen This list constitutes the only possible election IDs that may be used to a Please select a verification type and click start start a verification If however no connection was possible you are still Universal Verification _ Individual Verification Start able to manually enter an election ID and try to click start If a connection was Verify the results of an entire election EXE v sub 2013 vsbfh 2013 possible the appropriate verification process will begin upon clicking start vsuzh 20 13 1 risis 2013 1 To choose one of the possible election IDs provided click on the downward facing arrow in the text box in the middle of the screen A list of the possible election I
51. pear The two remaining results of a verification are special cases in which either the content for the verification has not yet been implemented by the Uni Vote team or an error occurred during the processing of the verification If a verification has yet to be implemented an orange question mark will be shown If an error was produced then a yellow warn symbol is shown In any case except a successful result additional information about why the test failed and what this means can be obtained through the Helper Text More information about this feature is available in the section Helper Text Illustration 8 Icons representing the four possible verification results UniVerifier File View Language Help Specification Entity Type Election Results 17 em an D ote U NDEPENDENT VERIFIER vote x Welcome Ind vsbfh 2013 x LTallier certificate for tallierBaldr SYSTEM SETUP Schnorr Schn ED Illustration 9 The verification output is displayed in a corresponding tab 5 4 Helper Text If a verification was not successful additional information about what went wrong may be obtained by clicking on or placing the mouse over the verification for which you would like to retrieve more information A small blue helper text will appear and provide a brief explanation of why the verification was not a success 5 5 Candidate Results This view
52. rt du m moire de Bachelor VoteVerifier Independent Verifier for UniVote Elections Berner Fachhochschule Haute cole sp cialis e bernoise Technik und Informatik Technique et informatique Abteilung Informatik Division informatique Erklarung der Diplomandinnen und Diplomanden D claration des dipl m e s Selbst ndige Arbeit Travail autonome Ich best tige mit meiner Unterschrift dass ich meine Bachelor Thesis selbst ndig durchgef hrt habe Alle Informationsquellen Fachiteratur Besprechungen mit Fachleuten usw die wesentlich zu meiner Arbeit beigetragen haben sind in meinem Arbeitsbericht im Anhang vollst ndig aufgef hrt Par ma signature je confirme avoir effectu mon m moire de Bachelor de mani re autonome Toutes les sources d information litt rature sp cialis e discussions avec sp cialistes etc qui m ont fortement aid es dans mon travail sont int gralement mentionn es dans l annexe de mon m moire Name Nom Vorname Pr nom Oca a G 9S Sey Q Datum Date Unterschrift Signature Dieses Formular ist dem Bachelor Thesis Bericht beizulegen Ce formulaire doit tre joint au rapport du m moire de Bachelor VoteVerifier Independent Verifier for UniVote Elections Basement e Contents Ta e seis Me ten nn tte eee nanos ihe nt ere CNE enda 1 LA Gite le GE 1 1 2 TREMMER SEE ENE ER te aces M eh EE SR iat aah T 1 LS Ee 2 1 41 e ln 3 1 5 Project Planning EEE Aude 4 A A Ee ENE
53. ryptographic statement generated by other parties e Election Administrator EA the EA defines some parameters such as who are the talliers and who are the mixers or for example the election choices It usually requests that an election be run e Tallier T a tallier is responsible for the generation of a part of the encryption key These parts then form an encryption key that can be used by a voter to encrypt a vote VoteVerifier Independent Verifier for UniVote Elections e Mixer M a Mixer is used to mix for example the encrypted votes in order to avoid a possible association between a voter and his vote e Voter V a voter who takes part to an election Now we can list the phases of the voting Each of them uses the cryptographic primitives we have listed in the previous section and our software follow this phases in order to perform a verification In the voting protocol of UniVote there are six phases 1 Public parameters where the public parameters and the certificates are generated 2 Registration phase during this phase a voter registers itself in the UniVote system 3 Election setup where the election specific parameters are generated 4 Election preparation this phase happens shortly before an election starts and here will be for example defined the voting choices 5 Election period during this phase we are in the middle of an election Here we can for example find the creation and casting of a vote 6 Mixi
54. s stored in a variable and the file name is shown to the user Use Case 9 Use Case UC9 Select Start Primary Actor Voter Success Guarantee The verification is carried out Main Success Scenario 1 The user starts the program or clicks on the Welcome tab VoteVerifier Independent Verifier for UniVote Elections 4C 2 The user clicks on the start button 3 new tab appears with the name of the election ID for which a verification is being performed 4 The tab becomes the active visible tab 5 The user sees the verification results appear in the default organization which is according to specification After Verification has been Started Use Case 10 Use Case UC10 Return to Welcome Screen Primary Actor Voter Success Guarantee After starting a verification the use clicks on the Welcome tab and is presented with the setup options to begin a new verification process Main Success Scenario 1 The user clicks on the Welcome tab 2 The Welcome tab is set as the active visible tab 3 The choices to start a new verification are visible Use case 11 Use Case UC11 Close a Tab Primary Actor Voter Success Guarantee The tab in which the user has clicked the x closes and the next tab to the left become the active visible tab Main Success Scenario 1 The user clicks on the x in the tab section of the tabbed window 2 The currently active visible tab
55. shows the results of the elections It Fle View Language i e lt Vio Le iNoeeen EEN provides the information of how many votes were Weis iris Mivote received by which candidates and parties The choice ee D hem Election Results which is located after the choices for organizing the verification results will take you to this view The results are also organized in table form lene 2 according to political party In this section on one E e view is possible Help The table header shows the name of the party and how suan gees sti many votes it received The content of each table lists ESCH the candidate for that party as well as how many Illustration 10 Election Results votes each candidate received displays the voting results of the elections 5 6 Errors and Exceptions If there were any serious problems during the verification process such as a system crash or broken contact with the election board you will be notified of them in the Errors and Exceptions text area at the top of the results panel In the odd case that there were so many errors that the screen became filled this text area will contain all this information and allow you to scroll through the information Le Specification Entity Type _ Election Results 17 Errors and Exceptions SYSTEM_SETUP 6 Thanks Thank you for using the VoteVerifier independent verification software for UniVote electr
56. sirable that all messages be sent over one point of entry to the GUI and so there was only one instance of the Messenger class which was passed upon creation to all objects which send messages to the GUI With this organization the classes in the main code are prevented from directly calling methods within classes that compose the GUI This is advantageous because changes in the GUI do not necessarily require changes in the main code The GUI simply is alerted that an event has occurred and is given information but is otherwise free to act to this information according to its own programming An example of this pattern involves the verification process during which the GUI must be informed of the results from a certain verification Upon completion of a verification the appropriate runner see verification process can call the method sendVrfResult in its messenger object A helper class called Verification Event is sent to the GUI which reacts appropriately to the Verification Event based on its contents The Verification Event contains various instance variables such as Strings for messages or even another helper class called Verification Result which contains the results of a verification VoteVerifier Independent Verifier for UniVote Elections With the extension of the functionality of the software to encompass execution of multiple verification processes at a time the single Messenger instance was no longer sufficient To identify inco
57. ta then with the public key of the signer he can verify the signature RSA signatures are used to guarantee the integrity of the data of UniVote 2 1 2 ElGamal ElGamal is another encryption scheme that works with public keys and it s based on the discrete log problem The particularity of this scheme is that is randomized so that for each equal input we will obtain every time a different output As a Schnorr s signature an ElGamal encryption will result in a tuple with two values The ElGamal system in UniVote is used to encrypt the votes 2 1 3 Schnorr Signatures The Schnorr signature scheme is another method to check the integrity of data and the eligibility of a voter to vote A Schnorr signature is mainly composed by two values and one possible advantage over an RSA signature is that it generates relatively short signatures In contrast to VoteVerifier Independent Verifier for UniVote Elections RSA that is based on the difficulty to factorize a number into prime factors Schnorr signature are based on the discrete log problem Schnorr signatures are used to prove the integrity of the encrypted vote of a voter 2 1 4 Non Interactive Zero Knowledge Proof A non interactive zero knowledge proof is a method used to prove the knowledge of a certain value The verifier the one who verifies if the prover knows the value can through some mathematical operations say if the prover effectively knows a certain value The particularity of
58. tion receipt in the form of a QR code file which contains an election receipt in the form of a Quick Response Code OR Code To choose the election receipt you wish to verify click on the Select button and a file chooser window will be displayed Navigate to the file which contains the election receipt and click Select The program shows you the name of the file your have selected If you are content with your choice you may continue by clicking on Start The contents of the file you provided will be checked for validity If the file contains a valid QR Code a new tab will appear containing the verification results More about this verification tab can be found in the section entitled Viewing Results If the file provided did not contain a QR Code you will be notified of this and instructed to choose a different file 4 3 Additional Verification Processes It is possible to begin multiple verification processes that run parallel to each other To begin another verification process while another is running return at any time to the Welcome tab by clicking on it Here you will be able to follow the steps described in the sections Universal Verification and Individual Verification to begin another verification 5 Viewing Results 5 1 Tabs The verification results are displayed in a table in separate tabs for each election verification process The text at the top of each tab identifies the process to the user A tab with results for a univers
59. tionResult We can see how the verification will be performed In this case a class UniversalVerification has two runners SystemSetupRunner and ElectionSetupRunner These runners then have some implementers and we can see that for the ParametersImplementer a method will be called to verify prime numbers The second runner uses the RSAlmplementer to verify a signature The implementers can communicate with the board thanks to the ElectionBoardProxy object created by the verification class Basically we must first create a specialized Verification class and add some Runners For each Runner we choose the necessary Implementer used to perform the cryptographic We can see a certain level of flexibility because we can create the structure we want For example a UniversalVerficiation will use only certain Runners whereas an IndividualVerification will use a different set of runners The next chapters gives more detail about verifications runners and implementers VoteVerifier Independent Verifier for UniVote Elections 3 4 Implementer An implementer consists of a class specialized in the implementation of the various cryptographic checks We have 5 types of implementers at the bottom of our class infrastructure e CertificatesImplementer used to check certificates e RSAlmplementer used to verfiy RSA signatures e Schnorrimplementer for Schnorr signatures e __Parametersimplementer for other checks like prime numbers or parameters
60. tructed in the class MainGUI which contains in turn in a vertical layout the classes TitlePanel MiddlePanel and ConsolePanel The MiddlePanel contains then the tabbed panel with the welcome tab and creates any necessary new tabs for verification results Below is the simplified class diagram of the GUI components The GUI was designed to be as simple and user friendly as possible All attempts were made at keeping all functionality within one main GUI Frame and to minimize the occurrences of annoying pop up windows In the first version of the program it was imagined that the welcome window in which verification process could be setup would be a different window than where verification process results would be shown The design of this concept can be seen in the image below It was then decided that additional windows were not desirable as the program could be simplified by organizing multiple windows into a tab system within the main window of the user interface In the second concept the setup controls were designed to be placed above the results windows This simplified the organization of the windows but created a bit of a cramped feel as space was very limited at the top of the window and it was difficult to place the necessary information to guide the user through the setup process In the final version of the program the setup controls are placed into a welcome tab which is visible when the program stats up and to which the user
61. v value 5 paramW the parameter used for w 6 prime the prime number used for modulus operations 7 vExponentSign the sing of the s parameters sometimes we need a negative s After the various computations the knowledge of discrete log is verified only if the v is equal to W 3 5 Runner We decided to create these Runners in order to give to the program logic more organization A Runner is a component used to check only a portion of the verification process so we have created a Runner for each phase of the voting protocol For a UniversalVerificaiton we have created the following Runners e SystemSetupRunner ElectionSetupRunner e ElectionPreparationRunner e ElectionPeriodRunner e MixingTallingRunner e ResultRunner On the other hand an IndividualVerification has only two runners e __IndividualRunner e ResultRunner VoteVerifier Independent Verifier for UniVote Elections 2 Note that one can create a Runner for other purposes too For example we have the ResultRunner which is responsible for computing the results of an election We can make a small example of what the SystemSetupRunner effectively does Override public List lt VerificationResult gt run is Schnorr p prime VerificationResult vl paramImpl vrfPrime Config p VerificationType SETUP SCHNORR P msgr sendVrfMsg v1 partialResults add v1 Thread sleep SLEEP TIME is Schnorr q prime VerificationResult v2 paramImpl vrfPri
62. wed by initiation of a verification and ending with viewing and interpreting the results that are displayed by the program Please select a verification type and click start Verify the results of an entire election sub2013 T Illustration 1 The program is started up and the welcome panel is shown 3 Menu and Options The menu bar provides periphery functionality which include exiting the program displaying the text only output of a verification changing the language and viewing information about the development of the program as well as this manual 808 UniVerifier File View Language Help VAS E E b CELIA ge T Avote Illustration 2 The menu bar provides periphery functionality 3 1 File Menu The File menu contains the option to exit and close the program 3 2 View Menu 6800 UniVerifier File Language Help N Y Show Console 1 S ba en en ne ed de vote The View menu contains the option to show or hide the text console To toggle the visibility simply click on the check box next to the option show console The console will show Please select a verification type and click start up at the bottom of the screen and although the Universal Verification O Individual Verification Sur menu has disappeared the checkbox will now Verify the results of an entire election BE contain a check To hide the console again return the to the View menu and click once more upon the
63. ystem Specification Organization Sections System Setup Election Setup Election Preparation Election Period Mixing and Tallying By clicking on the other buttons next to Specification it is possible to change the organization Clicking on Entity will order the verification results according to the entity in the UniVote system responsible for generating the content that was verified Vois era TU TT Welcome Ind vsbfh 2013 x Lei Specification Entity Type O Election tesults 17 Errors and Exceptions Illustration 7 Control how the verification results are organized with three different views Entity Organization Sections Parameters CA EM EA Tallier Mixer Voters Finally it is possible to view the results sorted according to the type of verification that was carried out For example if a certificate was verified than the results of this verification will appear with all the other results for certificate verifications Type Organization Sections Parameters Certificate RSA NIZKP proofs 5 3 Interpreting results There are 4 possible outcomes for the verification results A result may pass fail not be implemented or have caused an error In the case that the result passed the verification a green checkmark will appear at the end of the line where the verification is described If the verification was unsuccessful then in place of a green checkmark a red x will ap

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