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bls_test.go
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bls_test.go
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//go:build relic
// +build relic
package crypto
import (
crand "crypto/rand"
"encoding/hex"
"fmt"
mrand "math/rand"
"testing"
"github.com/stretchr/testify/assert"
"github.com/stretchr/testify/require"
"github.com/onflow/flow-go/crypto/hash"
)
// TestBLSMainMethods is a sanity check of main signature scheme methods (keyGen, sign, verify)
func TestBLSMainMethods(t *testing.T) {
// test the key generation seed lengths
testKeyGenSeed(t, BLSBLS12381, KeyGenSeedMinLen, KeyGenSeedMaxLen)
// test the consistency with different inputs
hasher := NewExpandMsgXOFKMAC128("test tag")
testGenSignVerify(t, BLSBLS12381, hasher)
// specific signature test for BLS:
// Test a signature with a point encoded with a coordinate x not reduced mod p
// The same signature point with the x coordinate reduced passes verification.
// This test checks that:
// - signature decoding handles input x-coordinates larger than p (doesn't result in an exception)
// - signature decoding only accepts reduced x-coordinates to avoid signature malleability
t.Run("invalid x coordinate larger than p", func(t *testing.T) {
msg, err := hex.DecodeString("7f26ba692dc2da7ff828ef4675ff1cd6ab855fca0637b6dab295f1df8e51bc8bb1b8f0c6610aabd486cf1f098f2ddbc6691d94e10f928816f890a3d366ce46249836a595c7ea1828af52e899ba2ab627ab667113bb563918c5d5a787c414399487b4e3a7")
require.NoError(t, err)
validSig, err := hex.DecodeString("80b0cac2a0f4f8881913edf2b29065675dfed6f6f4e17e9b5d860a845d4e7d476b277d06a493b81482e63d8131f9f2fa")
require.NoError(t, err)
invalidSig, err := hex.DecodeString("9AB1DCACDA74DF22642F95A8F5DC123EC276227BE866915AC4B6DD2553FF736B89D37D0555E7B8143CE53D8131F99DA5")
require.NoError(t, err)
pkBytes, err := hex.DecodeString("a7ac85ac8ffd9d2611f73721a93ec92115f29d769dfa425fec2e2c26ab3e4e8089a961ab430639104262723e829b75e9190a05d8fc8d22a7ac78a18473cc3df146b5c4c9c8e46d5f208039384fe2fc018321f14c01641c3afff7558a2eb06463")
require.NoError(t, err)
pk, err := DecodePublicKey(BLSBLS12381, pkBytes)
require.NoError(t, err)
// sanity check of valid signature (P_x < p)
valid, err := pk.Verify(validSig, msg, hasher)
require.NoError(t, err)
require.True(t, valid)
// invalid signature (P'_x = P_x + p )
valid, err = pk.Verify(invalidSig, msg, hasher)
require.NoError(t, err)
assert.False(t, valid)
})
t.Run("private key equal to 1 and -1", func(t *testing.T) {
sk1Bytes := make([]byte, PrKeyLenBLSBLS12381)
sk1Bytes[PrKeyLenBLSBLS12381-1] = 1
sk1, err := DecodePrivateKey(BLSBLS12381, sk1Bytes)
require.NoError(t, err)
skMinus1Bytes := make([]byte, PrKeyLenBLSBLS12381)
copy(skMinus1Bytes, BLS12381Order)
skMinus1Bytes[PrKeyLenBLSBLS12381-1] -= 1
skMinus1, err := DecodePrivateKey(BLSBLS12381, skMinus1Bytes)
require.NoError(t, err)
for _, sk := range []PrivateKey{sk1, skMinus1} {
input := make([]byte, 100)
_, err = crand.Read(input)
require.NoError(t, err)
s, err := sk.Sign(input, hasher)
require.NoError(t, err)
pk := sk.PublicKey()
// test a valid signature
result, err := pk.Verify(s, input, hasher)
assert.NoError(t, err)
assert.True(t, result,
"Verification should succeed:\n signature:%s\n message:%x\n private key:%s", s, input, sk)
}
})
}
// Signing bench
func BenchmarkBLSBLS12381Sign(b *testing.B) {
halg := NewExpandMsgXOFKMAC128("bench tag")
benchSign(b, BLSBLS12381, halg)
}
// Verifying bench
func BenchmarkBLSBLS12381Verify(b *testing.B) {
halg := NewExpandMsgXOFKMAC128("bench tag")
benchVerify(b, BLSBLS12381, halg)
}
// utility function to generate a random BLS private key
func randomSK(t *testing.T, rand *mrand.Rand) PrivateKey {
seed := make([]byte, KeyGenSeedMinLen)
n, err := rand.Read(seed)
require.Equal(t, n, KeyGenSeedMinLen)
require.NoError(t, err)
sk, err := GeneratePrivateKey(BLSBLS12381, seed)
require.NoError(t, err)
return sk
}
// utility function to generate a non BLS private key
func invalidSK(t *testing.T) PrivateKey {
seed := make([]byte, KeyGenSeedMinLen)
n, err := crand.Read(seed)
require.Equal(t, n, KeyGenSeedMinLen)
require.NoError(t, err)
sk, err := GeneratePrivateKey(ECDSAP256, seed)
require.NoError(t, err)
return sk
}
// BLS tests
func TestBLSBLS12381Hasher(t *testing.T) {
rand := getPRG(t)
// generate a key pair
sk := randomSK(t, rand)
sig := make([]byte, SignatureLenBLSBLS12381)
msg := []byte("message")
// empty hasher
t.Run("Empty hasher", func(t *testing.T) {
_, err := sk.Sign(msg, nil)
assert.Error(t, err)
assert.True(t, IsNilHasherError(err))
_, err = sk.PublicKey().Verify(sig, msg, nil)
assert.Error(t, err)
assert.True(t, IsNilHasherError(err))
})
// short size hasher
t.Run("short size hasher", func(t *testing.T) {
s, err := sk.Sign(msg, hash.NewSHA2_256())
assert.Error(t, err)
assert.True(t, IsInvalidHasherSizeError(err))
assert.Nil(t, s)
valid, err := sk.PublicKey().Verify(sig, msg, hash.NewSHA2_256())
assert.Error(t, err)
assert.True(t, IsInvalidHasherSizeError(err))
assert.False(t, valid)
})
t.Run("NewExpandMsgXOFKMAC128 sanity check", func(t *testing.T) {
// test the parameter lengths of NewExpandMsgXOFKMAC128 are in the correct range
// h would be nil if the kmac inputs are invalid
h := internalExpandMsgXOFKMAC128(blsSigCipherSuite)
assert.NotNil(t, h)
})
t.Run("constants sanity check", func(t *testing.T) {
// test that the ciphersuites exceed 16 bytes as per draft-irtf-cfrg-hash-to-curve
// The tags used by internalExpandMsgXOFKMAC128 are at least len(ciphersuite) long
assert.GreaterOrEqual(t, len(blsSigCipherSuite), 16)
assert.GreaterOrEqual(t, len(blsPOPCipherSuite), 16)
})
t.Run("orthogonal PoP and signature hashing", func(t *testing.T) {
data := []byte("random_data")
// empty tag hasher
sigKmac := NewExpandMsgXOFKMAC128("")
h1 := sigKmac.ComputeHash(data)
// PoP hasher
h2 := popKMAC.ComputeHash(data)
assert.NotEqual(t, h1, h2)
})
}
// TestBLSEncodeDecode tests encoding and decoding of BLS keys
func TestBLSEncodeDecode(t *testing.T) {
// generic tests
testEncodeDecode(t, BLSBLS12381)
// specific tests for BLS
// zero private key
skBytes := make([]byte, PrKeyLenBLSBLS12381)
sk, err := DecodePrivateKey(BLSBLS12381, skBytes)
require.Error(t, err, "decoding identity private key should fail")
assert.True(t, IsInvalidInputsError(err))
assert.Nil(t, sk)
// identity public key
pkBytes := make([]byte, PubKeyLenBLSBLS12381)
pkBytes[0] = infinityPointHeader
pk, err := DecodePublicKey(BLSBLS12381, pkBytes)
require.NoError(t, err, "decoding identity public key should succeed")
assert.True(t, pk.Equals(IdentityBLSPublicKey()))
// invalid point
pkBytes = make([]byte, PubKeyLenBLSBLS12381)
pkBytes[0] = invalidBLSSignatureHeader
pk, err = DecodePublicKey(BLSBLS12381, pkBytes)
require.Error(t, err, "the key decoding should fail - key value is invalid")
assert.True(t, IsInvalidInputsError(err))
assert.Nil(t, pk)
// Test a public key serialization with a point encoded with a coordinate x with
// x[0] or x[1] not reduced mod p.
// The same public key point with x[0] and x[1] reduced passes decoding.
// This test checks that:
// - public key decoding handles input x-coordinates with x[0] and x[1] larger than p (doesn't result in an exception)
// - public key decoding only accepts reduced x[0] and x[1] to insure key serialization uniqueness.
// Although uniqueness of public key respresentation isn't a security property, some implementations
// may implicitely rely on the property.
// valid pk with x[0] < p and x[1] < p
validPk, err := hex.DecodeString("818d72183e3e908af5bd6c2e37494c749b88f0396d3fbc2ba4d9ea28f1c50d1c6a540ec8fe06b6d860f72ec9363db3b8038360809700d36d761cb266af6babe9a069dc7364d3502e84536bd893d5f09ec2dd4f07cae1f8a178ffacc450f9b9a2")
require.NoError(t, err)
_, err = DecodePublicKey(BLSBLS12381, validPk)
assert.NoError(t, err)
// invalidpk1 with x[0]+p and same x[1]
invalidPk1, err := hex.DecodeString("9B8E840277BE772540D913E47A94F94C00003BBE60C4CEEB0C0ABCC9E876034089000EC7AF5AB6D81AF62EC9363D5E63038360809700d36d761cb266af6babe9a069dc7364d3502e84536bd893d5f09ec2dd4f07cae1f8a178ffacc450f9b9a2")
require.NoError(t, err)
_, err = DecodePublicKey(BLSBLS12381, invalidPk1)
assert.Error(t, err)
// invalidpk1 with same x[0] and x[1]+p
invalidPk2, err := hex.DecodeString("818d72183e3e908af5bd6c2e37494c749b88f0396d3fbc2ba4d9ea28f1c50d1c6a540ec8fe06b6d860f72ec9363db3b81D84726AD080BA07C1385A1CF2B758C104E127F8585862EDEB843E798A86E6C2E1894F067C35F8A132FEACC450F9644D")
require.NoError(t, err)
_, err = DecodePublicKey(BLSBLS12381, invalidPk2)
assert.Error(t, err)
}
// TestBLSEquals tests equal for BLS keys
func TestBLSEquals(t *testing.T) {
testEquals(t, BLSBLS12381, ECDSAP256)
}
// TestBLSUtils tests some utility functions
func TestBLSUtils(t *testing.T) {
rand := getPRG(t)
// generate a key pair
sk := randomSK(t, rand)
// test Algorithm()
testKeysAlgorithm(t, sk, BLSBLS12381)
// test Size()
testKeySize(t, sk, PrKeyLenBLSBLS12381, PubKeyLenBLSBLS12381)
}
// BLS Proof of Possession test
func TestBLSPOP(t *testing.T) {
rand := getPRG(t)
seed := make([]byte, KeyGenSeedMinLen)
input := make([]byte, 100)
t.Run("PoP tests", func(t *testing.T) {
loops := 10
for j := 0; j < loops; j++ {
n, err := rand.Read(seed)
require.Equal(t, n, KeyGenSeedMinLen)
require.NoError(t, err)
sk, err := GeneratePrivateKey(BLSBLS12381, seed)
require.NoError(t, err)
_, err = rand.Read(input)
require.NoError(t, err)
s, err := BLSGeneratePOP(sk)
require.NoError(t, err)
pk := sk.PublicKey()
// test a valid PoP
result, err := BLSVerifyPOP(pk, s)
require.NoError(t, err)
assert.True(t, result, "Verification should succeed:\n signature:%s\n private key:%s", s, sk)
// test with a valid but different key
seed[0] ^= 1
wrongSk, err := GeneratePrivateKey(BLSBLS12381, seed)
require.NoError(t, err)
result, err = BLSVerifyPOP(wrongSk.PublicKey(), s)
require.NoError(t, err)
assert.False(t, result, "Verification should fail:\n signature:%s\n private key:%s", s, sk)
}
})
t.Run("invalid inputs", func(t *testing.T) {
// ecdsa key
sk := invalidSK(t)
s, err := BLSGeneratePOP(sk)
assert.True(t, IsNotBLSKeyError(err))
assert.Nil(t, s)
s = make([]byte, SignatureLenBLSBLS12381)
result, err := BLSVerifyPOP(sk.PublicKey(), s)
assert.True(t, IsNotBLSKeyError(err))
assert.False(t, result)
})
}
// BLS multi-signature
// signature aggregation sanity check
//
// Aggregate n signatures of the same message under different keys, and compare
// it against the signature of the message under an aggregated private key.
// Verify the aggregated signature using the multi-signature verification with
// one message.
func TestBLSAggregateSignatures(t *testing.T) {
rand := getPRG(t)
// random message
input := make([]byte, 100)
_, err := rand.Read(input)
require.NoError(t, err)
// hasher
kmac := NewExpandMsgXOFKMAC128("test tag")
// number of signatures to aggregate
sigsNum := mrand.Intn(100) + 1
sigs := make([]Signature, 0, sigsNum)
sks := make([]PrivateKey, 0, sigsNum)
pks := make([]PublicKey, 0, sigsNum)
var aggSig, expectedSig Signature
// create the signatures
for i := 0; i < sigsNum; i++ {
sk := randomSK(t, rand)
s, err := sk.Sign(input, kmac)
require.NoError(t, err)
sigs = append(sigs, s)
sks = append(sks, sk)
pks = append(pks, sk.PublicKey())
}
// all signatures are valid
t.Run("all valid signatures", func(t *testing.T) {
// aggregate private keys
aggSk, err := AggregateBLSPrivateKeys(sks)
require.NoError(t, err)
expectedSig, err := aggSk.Sign(input, kmac)
require.NoError(t, err)
// aggregate signatures
aggSig, err := AggregateBLSSignatures(sigs)
require.NoError(t, err)
// First check: check the signatures are equal
assert.Equal(t, aggSig, expectedSig,
"incorrect signature %s, should be %s, private keys are %s, input is %x",
aggSig, expectedSig, sks, input)
// Second check: Verify the aggregated signature
valid, err := VerifyBLSSignatureOneMessage(pks, aggSig, input, kmac)
require.NoError(t, err)
assert.True(t, valid,
"Verification of %s failed, signature should be %s private keys are %s, input is %x",
aggSig, expectedSig, sks, input)
})
// check if one signature is not correct
t.Run("one invalid signature", func(t *testing.T) {
input[0] ^= 1
randomIndex := mrand.Intn(sigsNum)
sigs[randomIndex], err = sks[randomIndex].Sign(input, kmac)
input[0] ^= 1
aggSig, err = AggregateBLSSignatures(sigs)
require.NoError(t, err)
assert.NotEqual(t, aggSig, expectedSig,
"signature %s shouldn't be %s private keys are %s, input is %x",
aggSig, expectedSig, sks, input)
valid, err := VerifyBLSSignatureOneMessage(pks, aggSig, input, kmac)
require.NoError(t, err)
assert.False(t, valid,
"verification of signature %s should fail, it shouldn't be %s private keys are %s, input is %x",
aggSig, expectedSig, sks, input)
sigs[randomIndex], err = sks[randomIndex].Sign(input, kmac)
require.NoError(t, err)
})
// check if one the public keys is not correct
t.Run("one invalid public key", func(t *testing.T) {
randomIndex := mrand.Intn(sigsNum)
newSk := randomSK(t, rand)
sks[randomIndex] = newSk
pks[randomIndex] = newSk.PublicKey()
aggSk, err := AggregateBLSPrivateKeys(sks)
require.NoError(t, err)
expectedSig, err = aggSk.Sign(input, kmac)
require.NoError(t, err)
assert.NotEqual(t, aggSig, expectedSig,
"signature %s shouldn't be %s, private keys are %s, input is %x, wrong key is of index %d",
aggSig, expectedSig, sks, input, randomIndex)
valid, err := VerifyBLSSignatureOneMessage(pks, aggSig, input, kmac)
require.NoError(t, err)
assert.False(t, valid,
"signature %s should fail, shouldn't be %s, private keys are %s, input is %x, wrong key is of index %d",
aggSig, expectedSig, sks, input, randomIndex)
})
t.Run("invalid inputs", func(t *testing.T) {
// test aggregating an empty signature list
aggSig, err = AggregateBLSSignatures(sigs[:0])
assert.Error(t, err)
assert.True(t, IsBLSAggregateEmptyListError(err))
assert.Nil(t, aggSig)
// test verification with an empty key list
result, err := VerifyBLSSignatureOneMessage(pks[:0], aggSig, input, kmac)
assert.Error(t, err)
assert.True(t, IsBLSAggregateEmptyListError(err))
assert.False(t, result)
// test with a signature of a wrong length
shortSig := sigs[0][:signatureLengthBLSBLS12381-1]
aggSig, err = AggregateBLSSignatures([]Signature{shortSig})
assert.Error(t, err)
assert.True(t, IsInvalidSignatureError(err))
assert.Nil(t, aggSig)
// test with an invalid signature of a correct length
invalidSig := BLSInvalidSignature()
aggSig, err = AggregateBLSSignatures([]Signature{invalidSig})
assert.Error(t, err)
assert.True(t, IsInvalidSignatureError(err))
assert.Nil(t, aggSig)
// test the empty key list
aggSk, err := AggregateBLSPrivateKeys(sks[:0])
assert.Error(t, err)
assert.True(t, IsBLSAggregateEmptyListError(err))
assert.Nil(t, aggSk)
// test with an invalid key type
sk := invalidSK(t)
aggSk, err = AggregateBLSPrivateKeys([]PrivateKey{sk})
assert.Error(t, err)
assert.True(t, IsNotBLSKeyError(err))
assert.Nil(t, aggSk)
})
}
// BLS multi-signature
// public keys aggregation sanity check
//
// Aggregate n public keys and their respective private keys and compare
// the public key of the aggregated private key is equal to the aggregated
// public key
func TestBLSAggregatePubKeys(t *testing.T) {
rand := getPRG(t)
// number of keys to aggregate
pkNum := mrand.Intn(100) + 1
pks := make([]PublicKey, 0, pkNum)
sks := make([]PrivateKey, 0, pkNum)
// create the signatures
for i := 0; i < pkNum; i++ {
sk := randomSK(t, rand)
sks = append(sks, sk)
pks = append(pks, sk.PublicKey())
}
// consistent private and public key aggregation
t.Run("correctness check", func(t *testing.T) {
// aggregate private keys
aggSk, err := AggregateBLSPrivateKeys(sks)
require.NoError(t, err)
expectedPk := aggSk.PublicKey()
// aggregate public keys
aggPk, err := AggregateBLSPublicKeys(pks)
assert.NoError(t, err)
assert.True(t, expectedPk.Equals(aggPk),
"incorrect public key %s, should be %s, public keys are %s",
aggPk, expectedPk, pks)
})
// aggregate an empty list
t.Run("empty list", func(t *testing.T) {
// private keys
aggSk, err := AggregateBLSPrivateKeys(sks[:0])
assert.Error(t, err)
assert.True(t, IsBLSAggregateEmptyListError(err))
assert.Nil(t, aggSk)
// public keys
aggPk, err := AggregateBLSPublicKeys(pks[:0])
assert.Error(t, err)
assert.True(t, IsBLSAggregateEmptyListError(err))
assert.Nil(t, aggPk)
})
// aggregate a list that includes the identity key,
// to check that identity key is indeed the identity element with regards to aggregation.
t.Run("aggregate a list that includes the identity key", func(t *testing.T) {
// aggregate the identity key with a non identity key
keys := []PublicKey{pks[0], IdentityBLSPublicKey()}
aggPkWithIdentity, err := AggregateBLSPublicKeys(keys)
assert.NoError(t, err)
assert.True(t, aggPkWithIdentity.Equals(pks[0]),
"incorrect public key %s, should be %s",
aggPkWithIdentity, pks[0])
})
t.Run("invalid inputs", func(t *testing.T) {
// empty list
aggPK, err := AggregateBLSPublicKeys(pks[:0])
assert.Error(t, err)
assert.True(t, IsBLSAggregateEmptyListError(err))
assert.Nil(t, aggPK)
// test with an invalid key type
pk := invalidSK(t).PublicKey()
aggPK, err = AggregateBLSPublicKeys([]PublicKey{pk})
assert.Error(t, err)
assert.True(t, IsNotBLSKeyError(err))
assert.Nil(t, aggPK)
})
// check that the public key corresponding to the zero private key is indeed identity
// The package doesn't allow to generate a zero private key. One way to obtain a zero
// private key is via aggrgeting opposite private keys
t.Run("public key of zero private key", func(t *testing.T) {
// sk1 is group order of bls12-381 minus one
groupOrderMinus1 := []byte{0x73, 0xED, 0xA7, 0x53, 0x29, 0x9D, 0x7D, 0x48, 0x33, 0x39,
0xD8, 0x08, 0x09, 0xA1, 0xD8, 0x05, 0x53, 0xBD, 0xA4, 0x02, 0xFF, 0xFE,
0x5B, 0xFE, 0xFF, 0xFF, 0xFF, 0xFF, 0x00, 0x00, 0x00, 0x00}
sk1, err := DecodePrivateKey(BLSBLS12381, groupOrderMinus1)
require.NoError(t, err)
// sk2 is 1
one := make([]byte, PrKeyLenBLSBLS12381)
one[PrKeyLenBLSBLS12381-1] = 1
sk2, err := DecodePrivateKey(BLSBLS12381, one)
require.NoError(t, err)
aggSK, err := AggregateBLSPrivateKeys([]PrivateKey{sk1, sk2})
require.NoError(t, err)
assert.True(t, aggSK.PublicKey().Equals(IdentityBLSPublicKey()))
})
}
// BLS multi-signature
// public keys removal sanity check
func TestBLSRemovePubKeys(t *testing.T) {
rand := getPRG(t)
// number of keys to aggregate
pkNum := mrand.Intn(100) + 1
pks := make([]PublicKey, 0, pkNum)
// generate public keys
for i := 0; i < pkNum; i++ {
sk := randomSK(t, rand)
pks = append(pks, sk.PublicKey())
}
// aggregate public keys
aggPk, err := AggregateBLSPublicKeys(pks)
require.NoError(t, err)
// random number of keys to remove (at least one key is left)
pkToRemoveNum := mrand.Intn(pkNum)
expectedPatrialPk, err := AggregateBLSPublicKeys(pks[pkToRemoveNum:])
require.NoError(t, err)
// check correctness
t.Run("equality check", func(t *testing.T) {
partialPk, err := RemoveBLSPublicKeys(aggPk, pks[:pkToRemoveNum])
require.NoError(t, err)
BLSkey, ok := expectedPatrialPk.(*pubKeyBLSBLS12381)
require.True(t, ok)
assert.True(t, BLSkey.Equals(partialPk),
"incorrect key %s, should be %s, keys are %s, index is %d",
partialPk, BLSkey, pks, pkToRemoveNum)
})
// remove an extra key and check inequality
t.Run("inequality check", func(t *testing.T) {
extraPk := randomSK(t, rand).PublicKey()
partialPk, err := RemoveBLSPublicKeys(aggPk, []PublicKey{extraPk})
assert.NoError(t, err)
BLSkey, ok := expectedPatrialPk.(*pubKeyBLSBLS12381)
require.True(t, ok)
assert.False(t, BLSkey.Equals(partialPk),
"incorrect key %s, should not be %s, keys are %s, index is %d, extra key is %s",
partialPk, BLSkey, pks, pkToRemoveNum, extraPk)
})
// specific test to remove all keys
t.Run("remove all keys", func(t *testing.T) {
identityPk, err := RemoveBLSPublicKeys(aggPk, pks)
require.NoError(t, err)
// identity public key is expected
randomPk := randomSK(t, rand).PublicKey()
randomPkPlusIdentityPk, err := AggregateBLSPublicKeys([]PublicKey{randomPk, identityPk})
require.NoError(t, err)
BLSRandomPk, ok := randomPk.(*pubKeyBLSBLS12381)
require.True(t, ok)
assert.True(t, BLSRandomPk.Equals(randomPkPlusIdentityPk),
"incorrect key %s, should be infinity point, keys are %s",
identityPk, pks)
})
// specific test with an empty slice of keys to remove
t.Run("remove empty list", func(t *testing.T) {
partialPk, err := RemoveBLSPublicKeys(aggPk, []PublicKey{})
require.NoError(t, err)
aggBLSkey, ok := aggPk.(*pubKeyBLSBLS12381)
require.True(t, ok)
assert.True(t, aggBLSkey.Equals(partialPk),
"incorrect key %s, should be %s",
partialPk, aggBLSkey)
})
t.Run("invalid inputs", func(t *testing.T) {
pk := invalidSK(t).PublicKey()
partialPk, err := RemoveBLSPublicKeys(pk, pks)
assert.Error(t, err)
assert.True(t, IsNotBLSKeyError(err))
assert.Nil(t, partialPk)
partialPk, err = RemoveBLSPublicKeys(aggPk, []PublicKey{pk})
assert.Error(t, err)
assert.True(t, IsNotBLSKeyError(err))
assert.Nil(t, partialPk)
})
}
// BLS multi-signature
// batch verification
//
// Verify n signatures of the same message under different keys using the fast
// batch verification technique and compares the result to verifying each signature
// separately.
func TestBLSBatchVerify(t *testing.T) {
rand := getPRG(t)
// random message
input := make([]byte, 100)
_, err := rand.Read(input)
require.NoError(t, err)
// hasher
kmac := NewExpandMsgXOFKMAC128("test tag")
// number of signatures to aggregate
sigsNum := rand.Intn(100) + 2
sigs := make([]Signature, 0, sigsNum)
sks := make([]PrivateKey, 0, sigsNum)
pks := make([]PublicKey, 0, sigsNum)
expectedValid := make([]bool, 0, sigsNum)
// create the signatures
for i := 0; i < sigsNum; i++ {
sk := randomSK(t, rand)
s, err := sk.Sign(input, kmac)
require.NoError(t, err)
sigs = append(sigs, s)
sks = append(sks, sk)
pks = append(pks, sk.PublicKey())
expectedValid = append(expectedValid, true)
}
// all signatures are valid
t.Run("all signatures are valid", func(t *testing.T) {
valid, err := BatchVerifyBLSSignaturesOneMessage(pks, sigs, input, kmac)
require.NoError(t, err)
assert.Equal(t, valid, expectedValid,
"Verification of %s failed, private keys are %s, input is %x, results is %v",
sigs, sks, input, valid)
})
// one valid signature
t.Run("one valid signature", func(t *testing.T) {
valid, err := BatchVerifyBLSSignaturesOneMessage(pks[:1], sigs[:1], input, kmac)
require.NoError(t, err)
assert.Equal(t, valid, expectedValid[:1],
"Verification of %s failed, private keys are %s, input is %x, results is %v",
sigs, sks, input, valid)
})
// pick a random number of invalid signatures
invalidSigsNum := rand.Intn(sigsNum-1) + 1
// generate a random permutation of indices to pick the
// invalid signatures.
indices := make([]int, 0, sigsNum)
for i := 0; i < sigsNum; i++ {
indices = append(indices, i)
}
rand.Shuffle(sigsNum, func(i, j int) {
indices[i], indices[j] = indices[j], indices[i]
})
// some signatures are invalid
t.Run("some signatures are invalid", func(t *testing.T) {
for i := 0; i < invalidSigsNum; i++ { // alter invalidSigsNum random signatures
alterSignature(sigs[indices[i]])
expectedValid[indices[i]] = false
}
valid, err := BatchVerifyBLSSignaturesOneMessage(pks, sigs, input, kmac)
require.NoError(t, err)
assert.Equal(t, expectedValid, valid,
"Verification of %s failed\n private keys are %s\n input is %x\n results is %v",
sigs, sks, input, valid)
})
// all signatures are invalid
t.Run("all signatures are invalid", func(t *testing.T) {
for i := invalidSigsNum; i < sigsNum; i++ { // alter the remaining random signatures
alterSignature(sigs[indices[i]])
expectedValid[indices[i]] = false
if i%5 == 0 {
sigs[indices[i]] = sigs[indices[i]][:3] // test the short signatures
}
}
valid, err := BatchVerifyBLSSignaturesOneMessage(pks, sigs, input, kmac)
require.NoError(t, err)
assert.Equal(t, valid, expectedValid,
"Verification of %s failed, private keys are %s, input is %x, results is %v",
sigs, sks, input, valid)
})
// test the empty list case
t.Run("empty list", func(t *testing.T) {
valid, err := BatchVerifyBLSSignaturesOneMessage(pks[:0], sigs[:0], input, kmac)
require.Error(t, err)
assert.True(t, IsBLSAggregateEmptyListError(err))
assert.Equal(t, valid, []bool{},
"verification should fail with empty list key, got %v", valid)
})
// test incorrect inputs
t.Run("inconsistent inputs", func(t *testing.T) {
valid, err := BatchVerifyBLSSignaturesOneMessage(pks[:len(pks)-1], sigs, input, kmac)
require.Error(t, err)
assert.True(t, IsInvalidInputsError(err))
assert.Equal(t, valid, []bool{},
"verification should fail with incorrect input lenghts, got %v", valid)
})
// test wrong hasher
t.Run("invalid hasher", func(t *testing.T) {
for i := 0; i < sigsNum; i++ {
expectedValid[i] = false
}
valid, err := BatchVerifyBLSSignaturesOneMessage(pks, sigs, input, nil)
require.Error(t, err)
assert.True(t, IsNilHasherError(err))
assert.Equal(t, valid, expectedValid,
"verification should fail with nil hasher, got %v", valid)
})
// test wrong key
t.Run("wrong key", func(t *testing.T) {
for i := 0; i < sigsNum; i++ {
expectedValid[i] = false
}
pks[0] = invalidSK(t).PublicKey()
valid, err := BatchVerifyBLSSignaturesOneMessage(pks, sigs, input, kmac)
require.Error(t, err)
assert.True(t, IsNotBLSKeyError(err))
assert.Equal(t, valid, expectedValid,
"verification should fail with invalid key, got %v", valid)
})
}
// alter or fix a signature
func alterSignature(s Signature) {
// this causes the signature to remain in G1 and be invalid
// OR to be a non-point in G1 (either on curve or not)
// which tests multiple error cases.
s[10] ^= 1
}
// Batch verify bench in the happy (all signatures are valid)
// and unhappy path (only one signature is invalid)
func BenchmarkBatchVerify(b *testing.B) {
// random message
input := make([]byte, 100)
_, err := crand.Read(input)
require.NoError(b, err)
// hasher
kmac := NewExpandMsgXOFKMAC128("bench tag")
sigsNum := 100
sigs := make([]Signature, 0, sigsNum)
pks := make([]PublicKey, 0, sigsNum)
seed := make([]byte, KeyGenSeedMinLen)
// create the signatures
for i := 0; i < sigsNum; i++ {
_, err := crand.Read(seed)
require.NoError(b, err)
sk, err := GeneratePrivateKey(BLSBLS12381, seed)
require.NoError(b, err)
s, err := sk.Sign(input, kmac)
require.NoError(b, err)
sigs = append(sigs, s)
pks = append(pks, sk.PublicKey())
}
// Batch verify bench when all signatures are valid
// (2) pairing compared to (2*n) pairings for the batch verification.
b.Run("happy path", func(b *testing.B) {
b.ResetTimer()
for i := 0; i < b.N; i++ {
// all signatures are valid
_, err := BatchVerifyBLSSignaturesOneMessage(pks, sigs, input, kmac)
require.NoError(b, err)
}
b.StopTimer()
})
// Batch verify bench when some signatures are invalid
// - if only one signaure is invalid (a valid point in G1):
// less than (2*2*log(n)) pairings compared to (2*n) pairings for the simple verification.
// - if all signatures are invalid (valid points in G1):
// (2*2*(n-1)) pairings compared to (2*n) pairings for the simple verification.
b.Run("unhappy path", func(b *testing.B) {
// only one invalid signature
alterSignature(sigs[sigsNum/2])
b.ResetTimer()
for i := 0; i < b.N; i++ {
// all signatures are valid
_, err := BatchVerifyBLSSignaturesOneMessage(pks, sigs, input, kmac)
require.NoError(b, err)
}
b.StopTimer()
})
}
// BLS multi-signature
// signature aggregation sanity check
//
// Aggregate n signatures of distinct messages under different keys,
// and verify the aggregated signature using the multi-signature verification with
// many message.
func TestBLSAggregateSignaturesManyMessages(t *testing.T) {
rand := getPRG(t)
// number of signatures to aggregate
sigsNum := mrand.Intn(20) + 1
sigs := make([]Signature, 0, sigsNum)
// number of keys
keysNum := mrand.Intn(sigsNum) + 1
sks := make([]PrivateKey, 0, keysNum)
// generate the keys
for i := 0; i < keysNum; i++ {
sk := randomSK(t, rand)
sks = append(sks, sk)
}
// number of messages (could be larger or smaller than the number of keys)
msgsNum := mrand.Intn(sigsNum) + 1
messages := make([][20]byte, msgsNum)
for i := 0; i < msgsNum; i++ {
_, err := rand.Read(messages[i][:])
require.NoError(t, err)
}
inputMsgs := make([][]byte, 0, sigsNum)
inputPks := make([]PublicKey, 0, sigsNum)
inputKmacs := make([]hash.Hasher, 0, sigsNum)
// create the signatures
for i := 0; i < sigsNum; i++ {
kmac := NewExpandMsgXOFKMAC128("test tag")
// pick a key randomly from the list
skRand := mrand.Intn(keysNum)
sk := sks[skRand]
// pick a message randomly from the list
msgRand := mrand.Intn(msgsNum)
msg := messages[msgRand][:]
// generate a signature
s, err := sk.Sign(msg, kmac)
require.NoError(t, err)
// update signatures and api inputs
sigs = append(sigs, s)
inputPks = append(inputPks, sk.PublicKey())
inputMsgs = append(inputMsgs, msg)
inputKmacs = append(inputKmacs, kmac)
}
var aggSig Signature
t.Run("correctness check", func(t *testing.T) {
// aggregate signatures
var err error
aggSig, err = AggregateBLSSignatures(sigs)
require.NoError(t, err)
// Verify the aggregated signature
valid, err := VerifyBLSSignatureManyMessages(inputPks, aggSig, inputMsgs, inputKmacs)
require.NoError(t, err)
assert.True(t, valid,
"Verification of %s failed, should be valid, private keys are %s, inputs are %x, input public keys are %s",
aggSig, sks, inputMsgs, inputPks)
})
// check if one of the signatures is not correct
t.Run("one signature is invalid", func(t *testing.T) {
randomIndex := mrand.Intn(sigsNum) // pick a random signature
messages[0][0] ^= 1 // make sure the signature is different
var err error
sigs[randomIndex], err = sks[0].Sign(messages[0][:], inputKmacs[0])
require.NoError(t, err)
messages[0][0] ^= 1
aggSig, err = AggregateBLSSignatures(sigs)
require.NoError(t, err)
valid, err := VerifyBLSSignatureManyMessages(inputPks, aggSig, inputMsgs, inputKmacs)
require.NoError(t, err)
assert.False(t, valid,
"Verification of %s should fail, private keys are %s, inputs are %x, input public keys are %s",
aggSig, sks, inputMsgs, inputPks)
})
// test the empty keys case
t.Run("empty list", func(t *testing.T) {
valid, err := VerifyBLSSignatureManyMessages(inputPks[:0], aggSig, inputMsgs, inputKmacs)
assert.Error(t, err)
assert.True(t, IsBLSAggregateEmptyListError(err))
assert.False(t, valid,
"verification should fail with an empty key list")
})
// test inconsistent input arrays
t.Run("inconsistent inputs", func(t *testing.T) {
// inconsistent lengths
valid, err := VerifyBLSSignatureManyMessages(inputPks, aggSig, inputMsgs[:sigsNum-1], inputKmacs)
assert.Error(t, err)
assert.True(t, IsInvalidInputsError(err))
assert.False(t, valid, "verification should fail with inconsistent messages and hashers")
// empty key list
valid, err = VerifyBLSSignatureManyMessages(inputPks[:0], aggSig, inputMsgs, inputKmacs)
assert.Error(t, err)
assert.True(t, IsBLSAggregateEmptyListError(err))
assert.False(t, valid, "verification should fail with empty list key")
// nil hasher
tmp := inputKmacs[0]
inputKmacs[0] = nil
valid, err = VerifyBLSSignatureManyMessages(inputPks, aggSig, inputMsgs, inputKmacs)
assert.Error(t, err)
assert.True(t, IsNilHasherError(err))
assert.False(t, valid, "verification should fail with nil hasher")
inputKmacs[0] = tmp
// wrong key
tmpPK := inputPks[0]
inputPks[0] = invalidSK(t).PublicKey()
valid, err = VerifyBLSSignatureManyMessages(inputPks, aggSig, inputMsgs, inputKmacs)
assert.Error(t, err)
assert.True(t, IsNotBLSKeyError(err))
assert.False(t, valid, "verification should fail with nil hasher")
inputPks[0] = tmpPK
})
}
// TestBLSErrorTypes verifies working of error-type-detecting functions
// such as `IsInvalidInputsError`.
func TestBLSErrorTypes(t *testing.T) {
t.Run("aggregateEmptyListError sanity", func(t *testing.T) {
err := blsAggregateEmptyListError
invInpError := invalidInputsErrorf("")
otherError := fmt.Errorf("some error")
assert.True(t, IsBLSAggregateEmptyListError(err))
assert.False(t, IsInvalidInputsError(err))
assert.False(t, IsBLSAggregateEmptyListError(invInpError))
assert.False(t, IsBLSAggregateEmptyListError(otherError))
assert.False(t, IsBLSAggregateEmptyListError(nil))
})
t.Run("notBLSKeyError sanity", func(t *testing.T) {
err := notBLSKeyError
invInpError := invalidInputsErrorf("")
otherError := fmt.Errorf("some error")
assert.True(t, IsNotBLSKeyError(err))
assert.False(t, IsInvalidInputsError(err))
assert.False(t, IsNotBLSKeyError(invInpError))
assert.False(t, IsNotBLSKeyError(otherError))
assert.False(t, IsNotBLSKeyError(nil))
})
}
// VerifyBLSSignatureManyMessages bench
// Bench the slowest case where all messages and public keys are distinct.
// (2*n) pairings without aggrgetion Vs (n+1) pairings with aggregation.
// The function is faster whenever there are redundant messages or public keys.
func BenchmarkVerifySignatureManyMessages(b *testing.B) {
// inputs
sigsNum := 100
inputKmacs := make([]hash.Hasher, 0, sigsNum)
sigs := make([]Signature, 0, sigsNum)
pks := make([]PublicKey, 0, sigsNum)
inputMsgs := make([][]byte, 0, sigsNum)
kmac := NewExpandMsgXOFKMAC128("bench tag")
seed := make([]byte, KeyGenSeedMinLen)
// create the signatures
for i := 0; i < sigsNum; i++ {
input := make([]byte, 100)
_, err := crand.Read(input)
require.NoError(b, err)
_, err = crand.Read(seed)
require.NoError(b, err)
sk, err := GeneratePrivateKey(BLSBLS12381, seed)
require.NoError(b, err)
s, err := sk.Sign(input, kmac)