mirror of
https://github.com/torvalds/linux.git
synced 2024-11-01 09:41:44 +00:00
e192be9d9a
The CRNG is faster, and we don't pretend to track entropy usage in the CRNG any more. Signed-off-by: Theodore Ts'o <tytso@mit.edu>
80 lines
2.6 KiB
C
80 lines
2.6 KiB
C
/*
|
|
* ChaCha20 256-bit cipher algorithm, RFC7539
|
|
*
|
|
* Copyright (C) 2015 Martin Willi
|
|
*
|
|
* This program is free software; you can redistribute it and/or modify
|
|
* it under the terms of the GNU General Public License as published by
|
|
* the Free Software Foundation; either version 2 of the License, or
|
|
* (at your option) any later version.
|
|
*/
|
|
|
|
#include <linux/kernel.h>
|
|
#include <linux/export.h>
|
|
#include <linux/bitops.h>
|
|
#include <linux/cryptohash.h>
|
|
#include <asm/unaligned.h>
|
|
#include <crypto/chacha20.h>
|
|
|
|
static inline u32 rotl32(u32 v, u8 n)
|
|
{
|
|
return (v << n) | (v >> (sizeof(v) * 8 - n));
|
|
}
|
|
|
|
extern void chacha20_block(u32 *state, void *stream)
|
|
{
|
|
u32 x[16], *out = stream;
|
|
int i;
|
|
|
|
for (i = 0; i < ARRAY_SIZE(x); i++)
|
|
x[i] = state[i];
|
|
|
|
for (i = 0; i < 20; i += 2) {
|
|
x[0] += x[4]; x[12] = rotl32(x[12] ^ x[0], 16);
|
|
x[1] += x[5]; x[13] = rotl32(x[13] ^ x[1], 16);
|
|
x[2] += x[6]; x[14] = rotl32(x[14] ^ x[2], 16);
|
|
x[3] += x[7]; x[15] = rotl32(x[15] ^ x[3], 16);
|
|
|
|
x[8] += x[12]; x[4] = rotl32(x[4] ^ x[8], 12);
|
|
x[9] += x[13]; x[5] = rotl32(x[5] ^ x[9], 12);
|
|
x[10] += x[14]; x[6] = rotl32(x[6] ^ x[10], 12);
|
|
x[11] += x[15]; x[7] = rotl32(x[7] ^ x[11], 12);
|
|
|
|
x[0] += x[4]; x[12] = rotl32(x[12] ^ x[0], 8);
|
|
x[1] += x[5]; x[13] = rotl32(x[13] ^ x[1], 8);
|
|
x[2] += x[6]; x[14] = rotl32(x[14] ^ x[2], 8);
|
|
x[3] += x[7]; x[15] = rotl32(x[15] ^ x[3], 8);
|
|
|
|
x[8] += x[12]; x[4] = rotl32(x[4] ^ x[8], 7);
|
|
x[9] += x[13]; x[5] = rotl32(x[5] ^ x[9], 7);
|
|
x[10] += x[14]; x[6] = rotl32(x[6] ^ x[10], 7);
|
|
x[11] += x[15]; x[7] = rotl32(x[7] ^ x[11], 7);
|
|
|
|
x[0] += x[5]; x[15] = rotl32(x[15] ^ x[0], 16);
|
|
x[1] += x[6]; x[12] = rotl32(x[12] ^ x[1], 16);
|
|
x[2] += x[7]; x[13] = rotl32(x[13] ^ x[2], 16);
|
|
x[3] += x[4]; x[14] = rotl32(x[14] ^ x[3], 16);
|
|
|
|
x[10] += x[15]; x[5] = rotl32(x[5] ^ x[10], 12);
|
|
x[11] += x[12]; x[6] = rotl32(x[6] ^ x[11], 12);
|
|
x[8] += x[13]; x[7] = rotl32(x[7] ^ x[8], 12);
|
|
x[9] += x[14]; x[4] = rotl32(x[4] ^ x[9], 12);
|
|
|
|
x[0] += x[5]; x[15] = rotl32(x[15] ^ x[0], 8);
|
|
x[1] += x[6]; x[12] = rotl32(x[12] ^ x[1], 8);
|
|
x[2] += x[7]; x[13] = rotl32(x[13] ^ x[2], 8);
|
|
x[3] += x[4]; x[14] = rotl32(x[14] ^ x[3], 8);
|
|
|
|
x[10] += x[15]; x[5] = rotl32(x[5] ^ x[10], 7);
|
|
x[11] += x[12]; x[6] = rotl32(x[6] ^ x[11], 7);
|
|
x[8] += x[13]; x[7] = rotl32(x[7] ^ x[8], 7);
|
|
x[9] += x[14]; x[4] = rotl32(x[4] ^ x[9], 7);
|
|
}
|
|
|
|
for (i = 0; i < ARRAY_SIZE(x); i++)
|
|
out[i] = cpu_to_le32(x[i] + state[i]);
|
|
|
|
state[12]++;
|
|
}
|
|
EXPORT_SYMBOL(chacha20_block);
|