package tz import ( "github.com/nspcc-dev/tzhash/gf127" ) const ( // Size is the size of a Tillich-Zémor hash sum in bytes. Size = 64 hashBlockSize = 128 ) type digest struct { // Stores matrix cells in the following order: // [ 0 2 ] // [ 1 3 ] // This is done to reuse the same digest between generic // and AVX2 implementation. x [4]GF127 } // New returns a new hash.Hash computing the Tillich-Zémor checksum. func New() *digest { d := new(digest) d.Reset() return d } // Sum returns Tillich-Zémor checksum of data. func Sum(data []byte) [Size]byte { d := new(digest) _, _ = d.Write(data) // no errors return d.checkSum() } func (d *digest) Sum(in []byte) []byte { // Make a copy of d so that caller can keep writing and summing. d0 := *d h := d0.checkSum() return append(in, h[:]...) } func (d *digest) checkSum() (b [Size]byte) { t := d.x[0].Bytes() copy(b[:], t[:]) t = d.x[2].Bytes() copy(b[16:], t[:]) t = d.x[1].Bytes() copy(b[32:], t[:]) t = d.x[3].Bytes() copy(b[48:], t[:]) return } func (d *digest) Reset() { d.x[0] = GF127{1, 0} d.x[1] = GF127{0, 0} d.x[2] = GF127{0, 0} d.x[3] = GF127{1, 0} } func (d *digest) Write(data []byte) (n int, err error) { return write(d, data) } func writeGeneric(d *digest, data []byte) (n int, err error) { n = len(data) tmp := new(GF127) for _, b := range data { mulBitRightGeneric(&d.x[0], &d.x[1], &d.x[2], &d.x[3], b&0x80 != 0, tmp) mulBitRightGeneric(&d.x[0], &d.x[1], &d.x[2], &d.x[3], b&0x40 != 0, tmp) mulBitRightGeneric(&d.x[0], &d.x[1], &d.x[2], &d.x[3], b&0x20 != 0, tmp) mulBitRightGeneric(&d.x[0], &d.x[1], &d.x[2], &d.x[3], b&0x10 != 0, tmp) mulBitRightGeneric(&d.x[0], &d.x[1], &d.x[2], &d.x[3], b&0x08 != 0, tmp) mulBitRightGeneric(&d.x[0], &d.x[1], &d.x[2], &d.x[3], b&0x04 != 0, tmp) mulBitRightGeneric(&d.x[0], &d.x[1], &d.x[2], &d.x[3], b&0x02 != 0, tmp) mulBitRightGeneric(&d.x[0], &d.x[1], &d.x[2], &d.x[3], b&0x01 != 0, tmp) } return } func (d *digest) Size() int { return Size } func (d *digest) BlockSize() int { return hashBlockSize } func mulBitRightGeneric(c00, c10, c01, c11 *GF127, bit bool, tmp *GF127) { if bit { *tmp = *c00 gf127.Mul10(c00, c00) gf127.Add(c00, c01, c00) gf127.Mul11(tmp, tmp) gf127.Add(c01, tmp, c01) *tmp = *c10 gf127.Mul10(c10, c10) gf127.Add(c10, c11, c10) gf127.Mul11(tmp, tmp) gf127.Add(c11, tmp, c11) } else { *tmp = *c00 gf127.Mul10(c00, c00) gf127.Add(c00, c01, c00) *c01 = *tmp *tmp = *c10 gf127.Mul10(c10, c10) gf127.Add(c10, c11, c10) *c11 = *tmp } }