mirror of
https://github.com/saymrwulf/swisspost-evoting-go-poc.git
synced 2026-09-04 20:23:55 +00:00
saymrwulf
d2cfbf291f
The voter now also submits E2 = Enc(vote, returnCodesPK[0]) and a plaintext- equality proof that E2 and the ballot's slot 0 encrypt the SAME vote. Every CC verifies this proof during ballot verification. This is the soundness link that makes the return code cast-as-intended: a client that encrypts one vote for the tally and a different one for the return-code channel is rejected, so the code the CCs compute from E2 necessarily reflects the tallied vote. - transcript: publish the combined return-codes public key. - voter stores returnCodePK from the (confidential) card delivery. - wire: plaintext-equality proof DTO. Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
80 lines
2.3 KiB
Go
80 lines
2.3 KiB
Go
package party
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import (
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"math/big"
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"github.com/user/evote/pkg/elgamal"
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emath "github.com/user/evote/pkg/math"
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"github.com/user/evote/pkg/mixnet"
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"github.com/user/evote/pkg/returncodes"
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"github.com/user/evote/pkg/zkp"
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)
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// The state structs below hold each party's PRIVATE state. Nothing here may be
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// read by another party except through an explicit signed message.
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// setupState is the setup component's working store while assembling cards.
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type setupState struct {
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primes []*big.Int
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votingCards []*votingCard
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mappingTable *returncodes.MappingTable
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electionPK elgamal.PublicKey
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returnCodePK elgamal.PublicKey
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}
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// ccState is a control component's private key material and mix state.
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type ccState struct {
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keyPair elgamal.KeyPair
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returnCodeSecret emath.ZqElement
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schnorrProofs []zkp.SchnorrProof
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// Tally working state.
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shuffle mixnet.VerifiableShuffle
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decProofs []zkp.DecryptionProof
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shuffleIn *elgamal.CiphertextVector
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shuffleOut *elgamal.CiphertextVector
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}
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// ebState is the electoral board's private key material.
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type ebState struct {
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passwords []string
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keyPair elgamal.KeyPair
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}
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// serverState is the voting server / ballot box.
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type serverState struct {
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mappingTable *returncodes.MappingTable
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ballotBox []encryptedBallot
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electionPK elgamal.PublicKey
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returnCodePK elgamal.PublicKey
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primes []*big.Int
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}
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// voterState is a voter client's private card and ballot secrets.
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type voterState struct {
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card *votingCard
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electionPK elgamal.PublicKey
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returnCodePK elgamal.PublicKey
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primes []*big.Int
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vcSK emath.ZqElement
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selected []int
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}
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// votingCard is a voter's credential bundle (private to the voter, produced by
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// the setup component and delivered over a confidential channel).
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type votingCard struct {
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VoterID string `json:"voter_id"`
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VerificationCardID string `json:"vc_id"`
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StartVotingKey string `json:"svk"`
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ChoiceReturnCodes []string `json:"choice_return_codes"`
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VoteConfirmCode string `json:"vote_confirm_code"`
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BallotCastingKey string `json:"bck"`
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}
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// encryptedBallot is a ballot as stored in the ballot box.
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type encryptedBallot struct {
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VoterID string
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VerificationCardID string
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Ciphertext elgamal.Ciphertext
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VcPK emath.GqElement
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}
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