arnaucube/go-iden3-crypto
1
0
Fork 0
mirror of https://github.com/arnaucube/go-iden3-crypto.git synced 2026-02-07 03:26:39 +01:00
Code Issues Packages Projects Releases Wiki Activity

Update Poseidon Hash function names, rm HashBytes

Browse Source 
Since Poseidon Hash is used because of compatibility in zkSNARK circuits, due
circuit constraints number, the hash method of [T]*big.Int is the one directly
compatible with the circuits, is the method which have the `Hash` name on it.
The method that can take arbitrary length of []*big.Int putting them in chunks
of [T]*big.Int and iterating, is called `HashSlice`. The `HashBytes` has been
removed, as is a method that will not be used in zkSNARK circuits due high
constraints number.

For zkSNARK circuits, should be used `poseidon.Hash([poseidon.T]*big.Int)`.
This commit is contained in:
arnaucube
2020-07-23 07:59:59 +02:00
parent 2c471ab545
commit f22be3cdee
3 changed files with 41 additions and 53 deletions
Download Patch File Download Diff File Expand all files Collapse all files

33
poseidon/poseidon.go
View File

@@ -120,8 +120,8 @@ func mix(state [T]*ff.Element, newState [T]*ff.Element, m [T][T]*ff.Element) {
}
}
// PoseidonHash computes the Poseidon hash for the given inputs
func PoseidonHash(inpBI [T]*big.Int) (*big.Int, error) {
// Hash computes the Poseidon hash for the given inputs
func Hash(inpBI [T]*big.Int) (*big.Int, error) {
if !utils.CheckBigIntArrayInField(inpBI[:]) {
return nil, errors.New("inputs values not inside Finite Field")
}
@@ -148,9 +148,9 @@ func PoseidonHash(inpBI [T]*big.Int) (*big.Int, error) {
return r, nil
}
// Hash performs the Poseidon hash over a ff.Element array
// HashSlice performs the Poseidon hash over a ff.Element array
// in chunks of 5 elements
func Hash(arr []*big.Int) (*big.Int, error) {
func HashSlice(arr []*big.Int) (*big.Int, error) {
r := big.NewInt(int64(1))
for i := 0; i < len(arr); i = i + T - 1 {
var toHash [T]*big.Int
@@ -167,7 +167,7 @@ func Hash(arr []*big.Int) (*big.Int, error) {
toHash[j] = big.NewInt(0)
}
ph, err := PoseidonHash(toHash)
ph, err := Hash(toHash)
if err != nil {
return nil, err
}
@@ -176,26 +176,3 @@ func Hash(arr []*big.Int) (*big.Int, error) {
return r, nil
}
// HashBytes hashes a msg byte slice by blocks of 31 bytes encoded as
// little-endian
func HashBytes(b []byte) *big.Int {
n := 31
bElems := make([]*big.Int, 0, len(b)/n+1)
for i := 0; i < len(b)/n; i++ {
v := big.NewInt(int64(0))
utils.SetBigIntFromLEBytes(v, b[n*i:n*(i+1)])
bElems = append(bElems, v)
}
if len(b)%n != 0 {
v := big.NewInt(int64(0))
utils.SetBigIntFromLEBytes(v, b[(len(b)/n)*n:])
bElems = append(bElems, v)
}
h, err := Hash(bElems)
if err != nil {
panic(err)
}
return h
}