88 lines
1.5 KiB
Go
88 lines
1.5 KiB
Go
package keccak
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import "hash"
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const Size = 256 / 8
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const BlockSize = 1600/8 - Size*2
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var round = roundGo
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// digest implements hash.Hash
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type digest struct {
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a [5][5]uint64 // a[y][x][z]
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buf [BlockSize]byte
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len int
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}
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func New() hash.Hash {
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return &digest{}
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}
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func (d *digest) Size() int { return Size }
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func (d *digest) BlockSize() int { return BlockSize }
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func (d *digest) Reset() {
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*d = digest{}
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}
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func (d *digest) Write(b []byte) (int, error) {
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written := len(b)
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for len(b) > 0 {
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n := copy(d.buf[d.len:], b)
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d.len += n
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b = b[n:]
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if d.len == BlockSize {
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d.flush()
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}
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}
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return written, nil
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}
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func (d *digest) flush() {
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b := d.buf[:]
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loop:
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for y := range d.a {
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for x := range d.a[0] {
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if len(b) == 0 {
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break loop
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}
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d.a[y][x] ^= le64dec(b)
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b = b[8:]
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}
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}
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keccakf(&d.a)
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d.len = 0
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}
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func keccakf(a *[5][5]uint64) {
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for i := 0; i < 24; i++ {
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round(a)
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a[0][0] ^= RC[i]
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}
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}
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func (d0 *digest) Sum(b []byte) []byte {
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d := *d0
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d.buf[d.len] = 0x01
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for i := d.len + 1; i < BlockSize; i++ {
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d.buf[i] = 0
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}
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d.buf[BlockSize-1] |= 0x80
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d.flush()
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b = le64enc(b, d.a[0][0])
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b = le64enc(b, d.a[0][1])
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b = le64enc(b, d.a[0][2])
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b = le64enc(b, d.a[0][3])
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return b
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}
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func le64dec(b []byte) uint64 {
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return uint64(b[0])<<0 | uint64(b[1])<<8 | uint64(b[2])<<16 | uint64(b[3])<<24 | uint64(b[4])<<32 | uint64(b[5])<<40 | uint64(b[6])<<48 | uint64(b[7])<<56
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}
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func le64enc(b []byte, x uint64) []byte {
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return append(b, byte(x), byte(x>>8), byte(x>>16), byte(x>>24), byte(x>>32), byte(x>>40), byte(x>>48), byte(x>>56))
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}
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