https://github.com/arnaucube/go-blindsecp256k1

Blind signatures over secp256k1 elliptic curve
https://github.com/arnaucube/go-blindsecp256k1

Last synced: about 9 hours ago
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Blind signatures over secp256k1 elliptic curve

• Host: GitHub
• URL: https://github.com/arnaucube/go-blindsecp256k1
• Owner: arnaucube
• License: gpl-3.0
• Created: 2021-01-10T13:03:56.000Z (almost 4 years ago)
• Default Branch: master
• Last Pushed: 2022-05-17T06:10:08.000Z (over 2 years ago)
• Last Synced: 2024-06-18T18:48:29.670Z (5 months ago)
• Language: Go
• Homepage:
• Size: 4.69 MB
• Stars: 17
• Watchers: 4
• Forks: 5
• Open Issues: 1
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

        
# go-blindsecp256k1 [![GoDoc](https://godoc.org/github.com/arnaucube/go-blindsecp256k1?status.svg)](https://godoc.org/github.com/arnaucube/go-blindsecp256k1) [![Go Report Card](https://goreportcard.com/badge/github.com/arnaucube/go-blindsecp256k1)](https://goreportcard.com/report/github.com/arnaucube/go-blindsecp256k1) [![Test](https://github.com/arnaucube/go-blindsecp256k1/workflows/Test/badge.svg)](https://github.com/arnaucube/go-blindsecp256k1/actions?query=workflow%3ATest)

Blind signature over [secp256k1](https://en.bitcoin.it/wiki/Secp256k1), based on *"[New Blind Signature Schemes Based on the (Elliptic Curve) Discrete Logarithm Problem](https://sci-hub.st/10.1109/iccke.2013.6682844)"* paper by Hamid Mala & Nafiseh Nezhadansari.

**WARNING**: this repo is experimental, do not use in production.

The implementation of this repo is compatible with https://github.com/arnaucube/blindsecp256k1-js

## Usage

```go

import (

	[...]

	"github.com/arnaucube/go-blindsecp256k1"

)

[...]

// errors are not handled for simplicity of the example

// signer: create new signer key pair

sk, _ := blindsecp256k1.NewPrivateKey()

signerPubK := sk.Public()

// signer: when user requests new R parameter to blind a new msg,

// create new signerR (public) with its secret k

k, signerR, _ := blindsecp256k1.NewRequestParameters()

// user: blinds the msg using signer's R

msg := new(big.Int).SetBytes([]byte("test"))

msgBlinded, userSecretData, _ := blindsecp256k1.Blind(msg, signerR)

// signer: signs the blinded message using its private key & secret k

sBlind, _ := sk.BlindSign(msgBlinded, k)

// user: unblinds the blinded signature

sig := blindsecp256k1.Unblind(sBlind, userSecretData)

// signature can be verified with signer PublicKey

verified := blindsecp256k1.Verify(msg, sig, signerPubK)

assert.True(t, verified)

```

Compression & decompression (allows to compress a point & public key (64 bytes) into 33 bytes, and a signature (96 bytes) into 65 bytes):

```go

p := blindsecp256k1.G // take the generator point as an example

// also, instead from G, we can start from a PublicKey, which can be converted

// into a Point with

p = pk.Point()

// compress point

b := p.Compress()

fmt.Println(hex.EncodeToString(b[:]))

// decompress point (recovering the original point)

p2, _ := blindsecp256k1.DecompressPoint(b)

assert.Equal(t, p, p2)

// compress signature

b = sig.Compress()

fmt.Println(hex.EncodeToString(b[:])) // 65 bytes

// decompress signature

sig2, _ := DecompressSignature(b)

assert.Equal(t, sig, sig2)

```

## WASM usage

WASM wrappers for browser usage can be found at the [wasm](https://github.com/arnaucube/go-blindsecp256k1/tree/master/wasm/) directory with an example in html&js.