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https://github.com/saymrwulf/swisspost-evoting-go-poc.git
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saymrwulf
e8b6f30871
Proof-of-concept reimplementation of the Swiss Post e-voting cryptographic protocol in Go. Single binary, 52 source files, 2 dependencies. Covers ElGamal encryption, Bayer-Groth verifiable shuffles, zero-knowledge proofs, return codes, and a full election ceremony demo.
27 lines
821 B
Go
27 lines
821 B
Go
package returncodes
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import (
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"math/big"
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emath "github.com/user/evote/pkg/math"
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)
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// EncodeVote encodes a set of selected option indices as a product of small primes.
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// Each option index maps to a small prime; the vote is the product of selected primes.
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func EncodeVote(selectedIndices []int, primes []*big.Int) *big.Int {
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result := big.NewInt(1)
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for _, idx := range selectedIndices {
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result.Mul(result, primes[idx])
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}
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return result
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}
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// EncodeVoteAsGqElement encodes a vote and returns it as a GqElement.
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func EncodeVoteAsGqElement(selectedIndices []int, primes []*big.Int, group *emath.GqGroup) emath.GqElement {
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product := EncodeVote(selectedIndices, primes)
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elem, err := emath.NewGqElement(product, group)
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if err != nil {
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panic("encoded vote is not a group member: " + err.Error())
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}
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return elem
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}
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