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// Copyright (c) 2017 The Bitcoin Core developers | ||
// Distributed under the MIT software license, see the accompanying | ||
// file COPYING or http://www.opensource.org/licenses/mit-license.php. | ||
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// Based on the public domain implementation 'merged' by D. J. Bernstein | ||
// See https://cr.yp.to/chacha.html. | ||
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#include "crypto/common.h" | ||
#include "crypto/chacha20.h" | ||
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#include <string.h> | ||
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constexpr static inline uint32_t rotl32(uint32_t v, int c) { return (v << c) | (v >> (32 - c)); } | ||
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#define QUARTERROUND(a,b,c,d) \ | ||
a += b; d = rotl32(d ^ a, 16); \ | ||
c += d; b = rotl32(b ^ c, 12); \ | ||
a += b; d = rotl32(d ^ a, 8); \ | ||
c += d; b = rotl32(b ^ c, 7); | ||
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static const unsigned char sigma[] = "expand 32-byte k"; | ||
static const unsigned char tau[] = "expand 16-byte k"; | ||
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void ChaCha20::SetKey(const unsigned char* k, size_t keylen) | ||
{ | ||
const unsigned char *constants; | ||
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input[4] = ReadLE32(k + 0); | ||
input[5] = ReadLE32(k + 4); | ||
input[6] = ReadLE32(k + 8); | ||
input[7] = ReadLE32(k + 12); | ||
if (keylen == 32) { /* recommended */ | ||
k += 16; | ||
constants = sigma; | ||
} else { /* keylen == 16 */ | ||
constants = tau; | ||
} | ||
input[8] = ReadLE32(k + 0); | ||
input[9] = ReadLE32(k + 4); | ||
input[10] = ReadLE32(k + 8); | ||
input[11] = ReadLE32(k + 12); | ||
input[0] = ReadLE32(constants + 0); | ||
input[1] = ReadLE32(constants + 4); | ||
input[2] = ReadLE32(constants + 8); | ||
input[3] = ReadLE32(constants + 12); | ||
input[12] = 0; | ||
input[13] = 0; | ||
input[14] = 0; | ||
input[15] = 0; | ||
} | ||
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ChaCha20::ChaCha20() | ||
{ | ||
memset(input, 0, sizeof(input)); | ||
} | ||
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ChaCha20::ChaCha20(const unsigned char* k, size_t keylen) | ||
{ | ||
SetKey(k, keylen); | ||
} | ||
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void ChaCha20::SetIV(uint64_t iv) | ||
{ | ||
input[14] = iv; | ||
input[15] = iv >> 32; | ||
} | ||
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void ChaCha20::Seek(uint64_t pos) | ||
{ | ||
input[12] = pos; | ||
input[13] = pos >> 32; | ||
} | ||
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void ChaCha20::Output(unsigned char* c, size_t bytes) | ||
{ | ||
uint32_t x0, x1, x2, x3, x4, x5, x6, x7, x8, x9, x10, x11, x12, x13, x14, x15; | ||
uint32_t j0, j1, j2, j3, j4, j5, j6, j7, j8, j9, j10, j11, j12, j13, j14, j15; | ||
unsigned char *ctarget = NULL; | ||
unsigned char tmp[64]; | ||
unsigned int i; | ||
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if (!bytes) return; | ||
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j0 = input[0]; | ||
j1 = input[1]; | ||
j2 = input[2]; | ||
j3 = input[3]; | ||
j4 = input[4]; | ||
j5 = input[5]; | ||
j6 = input[6]; | ||
j7 = input[7]; | ||
j8 = input[8]; | ||
j9 = input[9]; | ||
j10 = input[10]; | ||
j11 = input[11]; | ||
j12 = input[12]; | ||
j13 = input[13]; | ||
j14 = input[14]; | ||
j15 = input[15]; | ||
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for (;;) { | ||
if (bytes < 64) { | ||
ctarget = c; | ||
c = tmp; | ||
} | ||
x0 = j0; | ||
x1 = j1; | ||
x2 = j2; | ||
x3 = j3; | ||
x4 = j4; | ||
x5 = j5; | ||
x6 = j6; | ||
x7 = j7; | ||
x8 = j8; | ||
x9 = j9; | ||
x10 = j10; | ||
x11 = j11; | ||
x12 = j12; | ||
x13 = j13; | ||
x14 = j14; | ||
x15 = j15; | ||
for (i = 20;i > 0;i -= 2) { | ||
QUARTERROUND( x0, x4, x8,x12) | ||
QUARTERROUND( x1, x5, x9,x13) | ||
QUARTERROUND( x2, x6,x10,x14) | ||
QUARTERROUND( x3, x7,x11,x15) | ||
QUARTERROUND( x0, x5,x10,x15) | ||
QUARTERROUND( x1, x6,x11,x12) | ||
QUARTERROUND( x2, x7, x8,x13) | ||
QUARTERROUND( x3, x4, x9,x14) | ||
} | ||
x0 += j0; | ||
x1 += j1; | ||
x2 += j2; | ||
x3 += j3; | ||
x4 += j4; | ||
x5 += j5; | ||
x6 += j6; | ||
x7 += j7; | ||
x8 += j8; | ||
x9 += j9; | ||
x10 += j10; | ||
x11 += j11; | ||
x12 += j12; | ||
x13 += j13; | ||
x14 += j14; | ||
x15 += j15; | ||
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++j12; | ||
if (!j12) ++j13; | ||
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WriteLE32(c + 0, x0); | ||
WriteLE32(c + 4, x1); | ||
WriteLE32(c + 8, x2); | ||
WriteLE32(c + 12, x3); | ||
WriteLE32(c + 16, x4); | ||
WriteLE32(c + 20, x5); | ||
WriteLE32(c + 24, x6); | ||
WriteLE32(c + 28, x7); | ||
WriteLE32(c + 32, x8); | ||
WriteLE32(c + 36, x9); | ||
WriteLE32(c + 40, x10); | ||
WriteLE32(c + 44, x11); | ||
WriteLE32(c + 48, x12); | ||
WriteLE32(c + 52, x13); | ||
WriteLE32(c + 56, x14); | ||
WriteLE32(c + 60, x15); | ||
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if (bytes <= 64) { | ||
if (bytes < 64) { | ||
for (i = 0;i < bytes;++i) ctarget[i] = c[i]; | ||
} | ||
input[12] = j12; | ||
input[13] = j13; | ||
return; | ||
} | ||
bytes -= 64; | ||
c += 64; | ||
} | ||
} |
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// Copyright (c) 2017 The Bitcoin Core developers | ||
// Distributed under the MIT software license, see the accompanying | ||
// file COPYING or http://www.opensource.org/licenses/mit-license.php. | ||
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#ifndef BITCOIN_CRYPTO_CHACHA20_H | ||
#define BITCOIN_CRYPTO_CHACHA20_H | ||
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#include <stdint.h> | ||
#include <stdlib.h> | ||
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/** A PRNG class for ChaCha20. */ | ||
class ChaCha20 | ||
{ | ||
private: | ||
uint32_t input[16]; | ||
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public: | ||
ChaCha20(); | ||
ChaCha20(const unsigned char* key, size_t keylen); | ||
void SetKey(const unsigned char* key, size_t keylen); | ||
void SetIV(uint64_t iv); | ||
void Seek(uint64_t pos); | ||
void Output(unsigned char* output, size_t bytes); | ||
}; | ||
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#endif // BITCOIN_CRYPTO_CHACHA20_H |
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