diff options
Diffstat (limited to 'lib/chacha.c')
| -rw-r--r-- | lib/chacha.c | 113 |
1 files changed, 0 insertions, 113 deletions
diff --git a/lib/chacha.c b/lib/chacha.c deleted file mode 100644 index c7c9826564d31d..00000000000000 --- a/lib/chacha.c +++ /dev/null @@ -1,113 +0,0 @@ -// SPDX-License-Identifier: GPL-2.0-or-later -/* - * The "hash function" used as the core of the ChaCha stream cipher (RFC7539) - * - * Copyright (C) 2015 Martin Willi - */ - -#include <linux/kernel.h> -#include <linux/export.h> -#include <linux/bitops.h> -#include <linux/cryptohash.h> -#include <asm/unaligned.h> -#include <crypto/chacha.h> - -static void chacha_permute(u32 *x, int nrounds) -{ - int i; - - /* whitelist the allowed round counts */ - WARN_ON_ONCE(nrounds != 20 && nrounds != 12); - - for (i = 0; i < nrounds; i += 2) { - x[0] += x[4]; x[12] = rol32(x[12] ^ x[0], 16); - x[1] += x[5]; x[13] = rol32(x[13] ^ x[1], 16); - x[2] += x[6]; x[14] = rol32(x[14] ^ x[2], 16); - x[3] += x[7]; x[15] = rol32(x[15] ^ x[3], 16); - - x[8] += x[12]; x[4] = rol32(x[4] ^ x[8], 12); - x[9] += x[13]; x[5] = rol32(x[5] ^ x[9], 12); - x[10] += x[14]; x[6] = rol32(x[6] ^ x[10], 12); - x[11] += x[15]; x[7] = rol32(x[7] ^ x[11], 12); - - x[0] += x[4]; x[12] = rol32(x[12] ^ x[0], 8); - x[1] += x[5]; x[13] = rol32(x[13] ^ x[1], 8); - x[2] += x[6]; x[14] = rol32(x[14] ^ x[2], 8); - x[3] += x[7]; x[15] = rol32(x[15] ^ x[3], 8); - - x[8] += x[12]; x[4] = rol32(x[4] ^ x[8], 7); - x[9] += x[13]; x[5] = rol32(x[5] ^ x[9], 7); - x[10] += x[14]; x[6] = rol32(x[6] ^ x[10], 7); - x[11] += x[15]; x[7] = rol32(x[7] ^ x[11], 7); - - x[0] += x[5]; x[15] = rol32(x[15] ^ x[0], 16); - x[1] += x[6]; x[12] = rol32(x[12] ^ x[1], 16); - x[2] += x[7]; x[13] = rol32(x[13] ^ x[2], 16); - x[3] += x[4]; x[14] = rol32(x[14] ^ x[3], 16); - - x[10] += x[15]; x[5] = rol32(x[5] ^ x[10], 12); - x[11] += x[12]; x[6] = rol32(x[6] ^ x[11], 12); - x[8] += x[13]; x[7] = rol32(x[7] ^ x[8], 12); - x[9] += x[14]; x[4] = rol32(x[4] ^ x[9], 12); - - x[0] += x[5]; x[15] = rol32(x[15] ^ x[0], 8); - x[1] += x[6]; x[12] = rol32(x[12] ^ x[1], 8); - x[2] += x[7]; x[13] = rol32(x[13] ^ x[2], 8); - x[3] += x[4]; x[14] = rol32(x[14] ^ x[3], 8); - - x[10] += x[15]; x[5] = rol32(x[5] ^ x[10], 7); - x[11] += x[12]; x[6] = rol32(x[6] ^ x[11], 7); - x[8] += x[13]; x[7] = rol32(x[7] ^ x[8], 7); - x[9] += x[14]; x[4] = rol32(x[4] ^ x[9], 7); - } -} - -/** - * chacha_block - generate one keystream block and increment block counter - * @state: input state matrix (16 32-bit words) - * @stream: output keystream block (64 bytes) - * @nrounds: number of rounds (20 or 12; 20 is recommended) - * - * This is the ChaCha core, a function from 64-byte strings to 64-byte strings. - * The caller has already converted the endianness of the input. This function - * also handles incrementing the block counter in the input matrix. - */ -void chacha_block(u32 *state, u8 *stream, int nrounds) -{ - u32 x[16]; - int i; - - memcpy(x, state, 64); - - chacha_permute(x, nrounds); - - for (i = 0; i < ARRAY_SIZE(x); i++) - put_unaligned_le32(x[i] + state[i], &stream[i * sizeof(u32)]); - - state[12]++; -} -EXPORT_SYMBOL(chacha_block); - -/** - * hchacha_block - abbreviated ChaCha core, for XChaCha - * @in: input state matrix (16 32-bit words) - * @out: output (8 32-bit words) - * @nrounds: number of rounds (20 or 12; 20 is recommended) - * - * HChaCha is the ChaCha equivalent of HSalsa and is an intermediate step - * towards XChaCha (see https://cr.yp.to/snuffle/xsalsa-20081128.pdf). HChaCha - * skips the final addition of the initial state, and outputs only certain words - * of the state. It should not be used for streaming directly. - */ -void hchacha_block(const u32 *in, u32 *out, int nrounds) -{ - u32 x[16]; - - memcpy(x, in, 64); - - chacha_permute(x, nrounds); - - memcpy(&out[0], &x[0], 16); - memcpy(&out[4], &x[12], 16); -} -EXPORT_SYMBOL(hchacha_block); |
