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// Copyright (c) 2016 Andreas Auernhammer. All rights reserved.
// Use of this source code is governed by a license that can be
// found in the LICENSE file.
package chacha
import "encoding/binary"
var sigma = [4]uint32{0x61707865, 0x3320646e, 0x79622d32, 0x6b206574}
func xorKeyStreamGeneric(dst, src []byte, block, state *[64]byte, rounds int) int {
for len(src) >= 64 {
chachaGeneric(block, state, rounds)
for i, v := range block {
dst[i] = src[i] ^ v
}
src = src[64:]
dst = dst[64:]
}
n := len(src)
if n > 0 {
chachaGeneric(block, state, rounds)
for i, v := range src {
dst[i] = v ^ block[i]
}
}
return n
}
func chachaGeneric(dst *[64]byte, state *[64]byte, rounds int) {
v00 := binary.LittleEndian.Uint32(state[0:])
v01 := binary.LittleEndian.Uint32(state[4:])
v02 := binary.LittleEndian.Uint32(state[8:])
v03 := binary.LittleEndian.Uint32(state[12:])
v04 := binary.LittleEndian.Uint32(state[16:])
v05 := binary.LittleEndian.Uint32(state[20:])
v06 := binary.LittleEndian.Uint32(state[24:])
v07 := binary.LittleEndian.Uint32(state[28:])
v08 := binary.LittleEndian.Uint32(state[32:])
v09 := binary.LittleEndian.Uint32(state[36:])
v10 := binary.LittleEndian.Uint32(state[40:])
v11 := binary.LittleEndian.Uint32(state[44:])
v12 := binary.LittleEndian.Uint32(state[48:])
v13 := binary.LittleEndian.Uint32(state[52:])
v14 := binary.LittleEndian.Uint32(state[56:])
v15 := binary.LittleEndian.Uint32(state[60:])
s00, s01, s02, s03, s04, s05, s06, s07 := v00, v01, v02, v03, v04, v05, v06, v07
s08, s09, s10, s11, s12, s13, s14, s15 := v08, v09, v10, v11, v12, v13, v14, v15
for i := 0; i < rounds; i += 2 {
v00 += v04
v12 ^= v00
v12 = (v12 << 16) | (v12 >> 16)
v08 += v12
v04 ^= v08
v04 = (v04 << 12) | (v04 >> 20)
v00 += v04
v12 ^= v00
v12 = (v12 << 8) | (v12 >> 24)
v08 += v12
v04 ^= v08
v04 = (v04 << 7) | (v04 >> 25)
v01 += v05
v13 ^= v01
v13 = (v13 << 16) | (v13 >> 16)
v09 += v13
v05 ^= v09
v05 = (v05 << 12) | (v05 >> 20)
v01 += v05
v13 ^= v01
v13 = (v13 << 8) | (v13 >> 24)
v09 += v13
v05 ^= v09
v05 = (v05 << 7) | (v05 >> 25)
v02 += v06
v14 ^= v02
v14 = (v14 << 16) | (v14 >> 16)
v10 += v14
v06 ^= v10
v06 = (v06 << 12) | (v06 >> 20)
v02 += v06
v14 ^= v02
v14 = (v14 << 8) | (v14 >> 24)
v10 += v14
v06 ^= v10
v06 = (v06 << 7) | (v06 >> 25)
v03 += v07
v15 ^= v03
v15 = (v15 << 16) | (v15 >> 16)
v11 += v15
v07 ^= v11
v07 = (v07 << 12) | (v07 >> 20)
v03 += v07
v15 ^= v03
v15 = (v15 << 8) | (v15 >> 24)
v11 += v15
v07 ^= v11
v07 = (v07 << 7) | (v07 >> 25)
v00 += v05
v15 ^= v00
v15 = (v15 << 16) | (v15 >> 16)
v10 += v15
v05 ^= v10
v05 = (v05 << 12) | (v05 >> 20)
v00 += v05
v15 ^= v00
v15 = (v15 << 8) | (v15 >> 24)
v10 += v15
v05 ^= v10
v05 = (v05 << 7) | (v05 >> 25)
v01 += v06
v12 ^= v01
v12 = (v12 << 16) | (v12 >> 16)
v11 += v12
v06 ^= v11
v06 = (v06 << 12) | (v06 >> 20)
v01 += v06
v12 ^= v01
v12 = (v12 << 8) | (v12 >> 24)
v11 += v12
v06 ^= v11
v06 = (v06 << 7) | (v06 >> 25)
v02 += v07
v13 ^= v02
v13 = (v13 << 16) | (v13 >> 16)
v08 += v13
v07 ^= v08
v07 = (v07 << 12) | (v07 >> 20)
v02 += v07
v13 ^= v02
v13 = (v13 << 8) | (v13 >> 24)
v08 += v13
v07 ^= v08
v07 = (v07 << 7) | (v07 >> 25)
v03 += v04
v14 ^= v03
v14 = (v14 << 16) | (v14 >> 16)
v09 += v14
v04 ^= v09
v04 = (v04 << 12) | (v04 >> 20)
v03 += v04
v14 ^= v03
v14 = (v14 << 8) | (v14 >> 24)
v09 += v14
v04 ^= v09
v04 = (v04 << 7) | (v04 >> 25)
}
v00 += s00
v01 += s01
v02 += s02
v03 += s03
v04 += s04
v05 += s05
v06 += s06
v07 += s07
v08 += s08
v09 += s09
v10 += s10
v11 += s11
v12 += s12
v13 += s13
v14 += s14
v15 += s15
s12++
binary.LittleEndian.PutUint32(state[48:], s12)
if s12 == 0 { // indicates overflow
s13++
binary.LittleEndian.PutUint32(state[52:], s13)
}
binary.LittleEndian.PutUint32(dst[0:], v00)
binary.LittleEndian.PutUint32(dst[4:], v01)
binary.LittleEndian.PutUint32(dst[8:], v02)
binary.LittleEndian.PutUint32(dst[12:], v03)
binary.LittleEndian.PutUint32(dst[16:], v04)
binary.LittleEndian.PutUint32(dst[20:], v05)
binary.LittleEndian.PutUint32(dst[24:], v06)
binary.LittleEndian.PutUint32(dst[28:], v07)
binary.LittleEndian.PutUint32(dst[32:], v08)
binary.LittleEndian.PutUint32(dst[36:], v09)
binary.LittleEndian.PutUint32(dst[40:], v10)
binary.LittleEndian.PutUint32(dst[44:], v11)
binary.LittleEndian.PutUint32(dst[48:], v12)
binary.LittleEndian.PutUint32(dst[52:], v13)
binary.LittleEndian.PutUint32(dst[56:], v14)
binary.LittleEndian.PutUint32(dst[60:], v15)
}
func hChaCha20Generic(out *[32]byte, nonce *[16]byte, key *[32]byte) {
v00 := sigma[0]
v01 := sigma[1]
v02 := sigma[2]
v03 := sigma[3]
v04 := binary.LittleEndian.Uint32(key[0:])
v05 := binary.LittleEndian.Uint32(key[4:])
v06 := binary.LittleEndian.Uint32(key[8:])
v07 := binary.LittleEndian.Uint32(key[12:])
v08 := binary.LittleEndian.Uint32(key[16:])
v09 := binary.LittleEndian.Uint32(key[20:])
v10 := binary.LittleEndian.Uint32(key[24:])
v11 := binary.LittleEndian.Uint32(key[28:])
v12 := binary.LittleEndian.Uint32(nonce[0:])
v13 := binary.LittleEndian.Uint32(nonce[4:])
v14 := binary.LittleEndian.Uint32(nonce[8:])
v15 := binary.LittleEndian.Uint32(nonce[12:])
for i := 0; i < 20; i += 2 {
v00 += v04
v12 ^= v00
v12 = (v12 << 16) | (v12 >> 16)
v08 += v12
v04 ^= v08
v04 = (v04 << 12) | (v04 >> 20)
v00 += v04
v12 ^= v00
v12 = (v12 << 8) | (v12 >> 24)
v08 += v12
v04 ^= v08
v04 = (v04 << 7) | (v04 >> 25)
v01 += v05
v13 ^= v01
v13 = (v13 << 16) | (v13 >> 16)
v09 += v13
v05 ^= v09
v05 = (v05 << 12) | (v05 >> 20)
v01 += v05
v13 ^= v01
v13 = (v13 << 8) | (v13 >> 24)
v09 += v13
v05 ^= v09
v05 = (v05 << 7) | (v05 >> 25)
v02 += v06
v14 ^= v02
v14 = (v14 << 16) | (v14 >> 16)
v10 += v14
v06 ^= v10
v06 = (v06 << 12) | (v06 >> 20)
v02 += v06
v14 ^= v02
v14 = (v14 << 8) | (v14 >> 24)
v10 += v14
v06 ^= v10
v06 = (v06 << 7) | (v06 >> 25)
v03 += v07
v15 ^= v03
v15 = (v15 << 16) | (v15 >> 16)
v11 += v15
v07 ^= v11
v07 = (v07 << 12) | (v07 >> 20)
v03 += v07
v15 ^= v03
v15 = (v15 << 8) | (v15 >> 24)
v11 += v15
v07 ^= v11
v07 = (v07 << 7) | (v07 >> 25)
v00 += v05
v15 ^= v00
v15 = (v15 << 16) | (v15 >> 16)
v10 += v15
v05 ^= v10
v05 = (v05 << 12) | (v05 >> 20)
v00 += v05
v15 ^= v00
v15 = (v15 << 8) | (v15 >> 24)
v10 += v15
v05 ^= v10
v05 = (v05 << 7) | (v05 >> 25)
v01 += v06
v12 ^= v01
v12 = (v12 << 16) | (v12 >> 16)
v11 += v12
v06 ^= v11
v06 = (v06 << 12) | (v06 >> 20)
v01 += v06
v12 ^= v01
v12 = (v12 << 8) | (v12 >> 24)
v11 += v12
v06 ^= v11
v06 = (v06 << 7) | (v06 >> 25)
v02 += v07
v13 ^= v02
v13 = (v13 << 16) | (v13 >> 16)
v08 += v13
v07 ^= v08
v07 = (v07 << 12) | (v07 >> 20)
v02 += v07
v13 ^= v02
v13 = (v13 << 8) | (v13 >> 24)
v08 += v13
v07 ^= v08
v07 = (v07 << 7) | (v07 >> 25)
v03 += v04
v14 ^= v03
v14 = (v14 << 16) | (v14 >> 16)
v09 += v14
v04 ^= v09
v04 = (v04 << 12) | (v04 >> 20)
v03 += v04
v14 ^= v03
v14 = (v14 << 8) | (v14 >> 24)
v09 += v14
v04 ^= v09
v04 = (v04 << 7) | (v04 >> 25)
}
binary.LittleEndian.PutUint32(out[0:], v00)
binary.LittleEndian.PutUint32(out[4:], v01)
binary.LittleEndian.PutUint32(out[8:], v02)
binary.LittleEndian.PutUint32(out[12:], v03)
binary.LittleEndian.PutUint32(out[16:], v12)
binary.LittleEndian.PutUint32(out[20:], v13)
binary.LittleEndian.PutUint32(out[24:], v14)
binary.LittleEndian.PutUint32(out[28:], v15)
}
|
