| // Copyright 2012 The Go Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style |
| // license that can be found in the LICENSE file. |
| |
| // Package salsa provides low-level access to functions in the Salsa family. |
| package salsa // import "golang.org/x/crypto/salsa20/salsa" |
| |
| // Sigma is the Salsa20 constant for 256-bit keys. |
| var Sigma = [16]byte{'e', 'x', 'p', 'a', 'n', 'd', ' ', '3', '2', '-', 'b', 'y', 't', 'e', ' ', 'k'} |
| |
| // HSalsa20 applies the HSalsa20 core function to a 16-byte input in, 32-byte |
| // key k, and 16-byte constant c, and puts the result into the 32-byte array |
| // out. |
| func HSalsa20(out *[32]byte, in *[16]byte, k *[32]byte, c *[16]byte) { |
| x0 := uint32(c[0]) | uint32(c[1])<<8 | uint32(c[2])<<16 | uint32(c[3])<<24 |
| x1 := uint32(k[0]) | uint32(k[1])<<8 | uint32(k[2])<<16 | uint32(k[3])<<24 |
| x2 := uint32(k[4]) | uint32(k[5])<<8 | uint32(k[6])<<16 | uint32(k[7])<<24 |
| x3 := uint32(k[8]) | uint32(k[9])<<8 | uint32(k[10])<<16 | uint32(k[11])<<24 |
| x4 := uint32(k[12]) | uint32(k[13])<<8 | uint32(k[14])<<16 | uint32(k[15])<<24 |
| x5 := uint32(c[4]) | uint32(c[5])<<8 | uint32(c[6])<<16 | uint32(c[7])<<24 |
| x6 := uint32(in[0]) | uint32(in[1])<<8 | uint32(in[2])<<16 | uint32(in[3])<<24 |
| x7 := uint32(in[4]) | uint32(in[5])<<8 | uint32(in[6])<<16 | uint32(in[7])<<24 |
| x8 := uint32(in[8]) | uint32(in[9])<<8 | uint32(in[10])<<16 | uint32(in[11])<<24 |
| x9 := uint32(in[12]) | uint32(in[13])<<8 | uint32(in[14])<<16 | uint32(in[15])<<24 |
| x10 := uint32(c[8]) | uint32(c[9])<<8 | uint32(c[10])<<16 | uint32(c[11])<<24 |
| x11 := uint32(k[16]) | uint32(k[17])<<8 | uint32(k[18])<<16 | uint32(k[19])<<24 |
| x12 := uint32(k[20]) | uint32(k[21])<<8 | uint32(k[22])<<16 | uint32(k[23])<<24 |
| x13 := uint32(k[24]) | uint32(k[25])<<8 | uint32(k[26])<<16 | uint32(k[27])<<24 |
| x14 := uint32(k[28]) | uint32(k[29])<<8 | uint32(k[30])<<16 | uint32(k[31])<<24 |
| x15 := uint32(c[12]) | uint32(c[13])<<8 | uint32(c[14])<<16 | uint32(c[15])<<24 |
| |
| for i := 0; i < 20; i += 2 { |
| u := x0 + x12 |
| x4 ^= u<<7 | u>>(32-7) |
| u = x4 + x0 |
| x8 ^= u<<9 | u>>(32-9) |
| u = x8 + x4 |
| x12 ^= u<<13 | u>>(32-13) |
| u = x12 + x8 |
| x0 ^= u<<18 | u>>(32-18) |
| |
| u = x5 + x1 |
| x9 ^= u<<7 | u>>(32-7) |
| u = x9 + x5 |
| x13 ^= u<<9 | u>>(32-9) |
| u = x13 + x9 |
| x1 ^= u<<13 | u>>(32-13) |
| u = x1 + x13 |
| x5 ^= u<<18 | u>>(32-18) |
| |
| u = x10 + x6 |
| x14 ^= u<<7 | u>>(32-7) |
| u = x14 + x10 |
| x2 ^= u<<9 | u>>(32-9) |
| u = x2 + x14 |
| x6 ^= u<<13 | u>>(32-13) |
| u = x6 + x2 |
| x10 ^= u<<18 | u>>(32-18) |
| |
| u = x15 + x11 |
| x3 ^= u<<7 | u>>(32-7) |
| u = x3 + x15 |
| x7 ^= u<<9 | u>>(32-9) |
| u = x7 + x3 |
| x11 ^= u<<13 | u>>(32-13) |
| u = x11 + x7 |
| x15 ^= u<<18 | u>>(32-18) |
| |
| u = x0 + x3 |
| x1 ^= u<<7 | u>>(32-7) |
| u = x1 + x0 |
| x2 ^= u<<9 | u>>(32-9) |
| u = x2 + x1 |
| x3 ^= u<<13 | u>>(32-13) |
| u = x3 + x2 |
| x0 ^= u<<18 | u>>(32-18) |
| |
| u = x5 + x4 |
| x6 ^= u<<7 | u>>(32-7) |
| u = x6 + x5 |
| x7 ^= u<<9 | u>>(32-9) |
| u = x7 + x6 |
| x4 ^= u<<13 | u>>(32-13) |
| u = x4 + x7 |
| x5 ^= u<<18 | u>>(32-18) |
| |
| u = x10 + x9 |
| x11 ^= u<<7 | u>>(32-7) |
| u = x11 + x10 |
| x8 ^= u<<9 | u>>(32-9) |
| u = x8 + x11 |
| x9 ^= u<<13 | u>>(32-13) |
| u = x9 + x8 |
| x10 ^= u<<18 | u>>(32-18) |
| |
| u = x15 + x14 |
| x12 ^= u<<7 | u>>(32-7) |
| u = x12 + x15 |
| x13 ^= u<<9 | u>>(32-9) |
| u = x13 + x12 |
| x14 ^= u<<13 | u>>(32-13) |
| u = x14 + x13 |
| x15 ^= u<<18 | u>>(32-18) |
| } |
| out[0] = byte(x0) |
| out[1] = byte(x0 >> 8) |
| out[2] = byte(x0 >> 16) |
| out[3] = byte(x0 >> 24) |
| |
| out[4] = byte(x5) |
| out[5] = byte(x5 >> 8) |
| out[6] = byte(x5 >> 16) |
| out[7] = byte(x5 >> 24) |
| |
| out[8] = byte(x10) |
| out[9] = byte(x10 >> 8) |
| out[10] = byte(x10 >> 16) |
| out[11] = byte(x10 >> 24) |
| |
| out[12] = byte(x15) |
| out[13] = byte(x15 >> 8) |
| out[14] = byte(x15 >> 16) |
| out[15] = byte(x15 >> 24) |
| |
| out[16] = byte(x6) |
| out[17] = byte(x6 >> 8) |
| out[18] = byte(x6 >> 16) |
| out[19] = byte(x6 >> 24) |
| |
| out[20] = byte(x7) |
| out[21] = byte(x7 >> 8) |
| out[22] = byte(x7 >> 16) |
| out[23] = byte(x7 >> 24) |
| |
| out[24] = byte(x8) |
| out[25] = byte(x8 >> 8) |
| out[26] = byte(x8 >> 16) |
| out[27] = byte(x8 >> 24) |
| |
| out[28] = byte(x9) |
| out[29] = byte(x9 >> 8) |
| out[30] = byte(x9 >> 16) |
| out[31] = byte(x9 >> 24) |
| } |