/* * 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 #include #include #include #include #include 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); ct>
path: root/net/dccp/sysctl.c
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