dash/go-bindings/README.md

bls-signatures

Go library that implements BLS signatures with aggregation as in Boneh, Drijvers, Neven 2018, using the relic toolkit for cryptographic primitives (pairings, EC, hashing).

This library is a Go port of the Chia Network's BLS lib.

Usage

go get github.com/dashpay/bls-signatures/go-bindings

Creating keys and signatures

// seed data must not be less 32 bytes length
seed := []byte{
    0, 50, 6, 244, 24, 199, 1, 25,
    52, 88, 192, 19, 18, 12, 89, 6,
    220, 18, 102, 58, 209, 82, 12, 62,
    89, 110, 182, 9, 44, 20, 254, 22,
}

// create a scheme, available three schemes: BasicSchemeMPL, AugSchemeMPL and PopSchemeMPL 
scheme := NewAugSchemeMPL()

// generate a private key using a seed data
sk, err := scheme.KeyGen(seed)
if err != nil {
    panic(err.Error())
}
// get a public key
pk, err := sk.G1Element()
if err != nil {
    panic(err.Error())
}

msg := []byte{1, 2, 3, 4, 5}

// make a signature for a message
sig := scheme.Sign(sk, msg)

// verify the message signature 
if !scheme.Verify(pk, msg, sig) {
    panic("failed the signature verification")
}

Serializing keys and signatures to bytes

skBytes := sk.Serialize()
pkBytes := pk.Serialize()
sigBytes := sig.Serialize()  

Loading keys and signatures from bytes

sk1, _ := PrivateKeyFromBytes(skBytes, false)
pk1, _ := G1ElementFromBytes(pkBytes)
sig1, _ := G2ElementFromBytes(sigBytes)

Create aggregate signatures

// Generate some more private keys
seed[0] = 1
sk1, _ := scheme.KeyGen(seed)
seed[0] = 2
sk2, _ := scheme.KeyGen(seed)
msg2 := []byte{1, 2, 3, 4, 5,6, 7}

// Generate first sig
pk1, _ := sk1.G1Element()
sig1 := scheme.Sign(sk1, msg)

// Generate second sig
pk2, _ := sk2.G1Element()
sig2 := scheme.Sign(sk2, msg2)

// Signatures can be non-interactively combined by anyone
var aggSig = scheme.AggregateSigs(sig1, sig2)

ok := scheme.AggregateVerify([]*G1Element{pk1, pk2}, [][]byte{msg, msg2}, aggSig)
if !ok {
    panic("failed a verification of the aggregated signature ")
}

Arbitrary trees of aggregates

seed[0] = 3
sk3, _ := scheme.KeyGen(seed)
pk3, _ := sk3.G1Element()
msg3 := []byte{100, 2, 254, 88, 90, 45, 23}
sig3 := scheme.Sign(sk3, msg3)

aggSigFinal := scheme.AggregateSigs(aggSig, sig3)
ok = scheme.AggregateVerify([]*G1Element{pk1, pk2, pk3}, [][]byte{msg, msg2, msg3}, aggSigFinal)
if !ok {
    panic("failed a verification of the aggregated signature ")
}

Very fast verification with Proof of Possession scheme

// create a proof possession scheme
popScheme := NewPopSchemeMPL()

// If the same msg is signed, you can use Proof of Possession (PopScheme) for efficiency
// A proof of possession MUST be passed around with the PK to ensure security.
popSig1 := popScheme.Sign(sk1, msg)
popSig2 := popScheme.Sign(sk2, msg)
popSig3 := popScheme.Sign(sk3, msg)
pop1 := popScheme.PopProve(sk1)
pop2 := popScheme.PopProve(sk2)
pop3 := popScheme.PopProve(sk3)

ok = popScheme.PopVerify(pk1, pop1)
if !ok {
    panic("failed a verification")
}
ok = popScheme.PopVerify(pk2, pop2)
if !ok {
    panic("failed a verification")
}
ok = popScheme.PopVerify(pk3, pop3)
if !ok {
    panic("failed a verification")
}

popSigAgg := popScheme.AggregateSigs(popSig1, popSig2, popSig3)
ok = popScheme.FastAggregateVerify([]*G1Element{pk1, pk2, pk3}, msg, popSigAgg)
if !ok {
    panic("failed a verification")
}

// Aggregate public key, indistinguishable from a single public key
var popAggPk = pk1.Add(pk2).Add(pk3)
ok = popScheme.Verify(popAggPk, msg, popSigAgg)
if !ok {
    panic("failed a verification")
}

// Aggregate private keys
var aggSk = PrivateKeyAggregate(sk1, sk2, sk3)
ok = popScheme.Sign(aggSk, msg).EqualTo(popSigAgg)
if !ok {
    panic("failed a verification")
}

HD keys using EIP-2333

// You can derive 'child' keys from any key, to create arbitrary trees. 4 byte indeces are used.
// Hardened (more secure, but no parent pk -> child pk)
masterSk, _ := augScheme.KeyGen(seed)

// Unhardened (less secure, but can go from parent pk -> child pk), BIP32 style
masterPk, _ := masterSk.G1Element()
childU := augScheme.DeriveChildSkUnhardened(masterSk, 22)
grandchildU := augScheme.DeriveChildSkUnhardened(childU, 0)

childUPk := augScheme.DeriveChildPkUnhardened(masterPk, 22)
grandchildUPk := augScheme.DeriveChildPkUnhardened(childUPk, 0)

pkChildU, _ := grandchildU.G1Element()
ok = grandchildUPk.EqualTo(pkChildU)
if !ok {
    panic("keys are not equal")
}

Do not forget to handle the errors properly, this part of the code was omitted deliberately

Use cases can be found in the original lib's readme.

Important note: Since this library is a port of the c++ library, so every piece of memory allocated by the library MUST be released on our own in GO. To release the memory is used runtime.SetFinalizer function, that will invoke automatically before GC release a memory allocated by GO.

Run tests

To run tests, build the library, then go to the go-bindings folder in the build directory and run

make test