268 lines
6.8 KiB
C
268 lines
6.8 KiB
C
/**********************************************************************
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* gosthash.c *
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* Copyright (c) 2005-2006 Cryptocom LTD *
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* This file is distributed under the same license as OpenSSL *
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* *
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* Implementation of GOST R 34.11-94 hash function *
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* uses on gost89.c and gost89.h Doesn't need OpenSSL *
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**********************************************************************/
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#include <string.h>
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#include "gost89.h"
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#include "gosthash.h"
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/*
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* Use OPENSSL_malloc for memory allocation if compiled with
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* -DOPENSSL_BUILD, and libc malloc otherwise
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*/
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#ifndef MYALLOC
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# ifdef OPENSSL_BUILD
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# include <openssl/crypto.h>
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# define MYALLOC(size) OPENSSL_malloc(size)
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# define MYFREE(ptr) OPENSSL_free(ptr)
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# else
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# define MYALLOC(size) malloc(size)
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# define MYFREE(ptr) free(ptr)
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# endif
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#endif
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/*
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* Following functions are various bit meshing routines used in GOST R
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* 34.11-94 algorithms
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*/
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static void swap_bytes(byte * w, byte * k)
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{
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int i, j;
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for (i = 0; i < 4; i++)
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for (j = 0; j < 8; j++)
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k[i + 4 * j] = w[8 * i + j];
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}
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/* was A_A */
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static void circle_xor8(const byte * w, byte * k)
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{
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byte buf[8];
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int i;
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memcpy(buf, w, 8);
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memmove(k, w + 8, 24);
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for (i = 0; i < 8; i++)
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k[i + 24] = buf[i] ^ k[i];
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}
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/* was R_R */
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static void transform_3(byte * data)
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{
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unsigned short int acc;
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acc = (data[0] ^ data[2] ^ data[4] ^ data[6] ^ data[24] ^ data[30]) |
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((data[1] ^ data[3] ^ data[5] ^ data[7] ^ data[25] ^ data[31]) << 8);
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memmove(data, data + 2, 30);
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data[30] = acc & 0xff;
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data[31] = acc >> 8;
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}
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/* Adds blocks of N bytes modulo 2**(8*n). Returns carry*/
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static int add_blocks(int n, byte * left, const byte * right)
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{
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int i;
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int carry = 0;
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int sum;
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for (i = 0; i < n; i++) {
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sum = (int)left[i] + (int)right[i] + carry;
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left[i] = sum & 0xff;
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carry = sum >> 8;
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}
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return carry;
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}
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/* Xor two sequences of bytes */
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static void xor_blocks(byte * result, const byte * a, const byte * b,
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size_t len)
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{
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size_t i;
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for (i = 0; i < len; i++)
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result[i] = a[i] ^ b[i];
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}
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/*
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* Calculate H(i+1) = Hash(Hi,Mi)
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* Where H and M are 32 bytes long
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*/
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static int hash_step(gost_ctx * c, byte * H, const byte * M)
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{
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byte U[32], W[32], V[32], S[32], Key[32];
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int i;
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/* Compute first key */
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xor_blocks(W, H, M, 32);
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swap_bytes(W, Key);
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/* Encrypt first 8 bytes of H with first key */
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gost_enc_with_key(c, Key, H, S);
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/* Compute second key */
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circle_xor8(H, U);
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circle_xor8(M, V);
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circle_xor8(V, V);
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xor_blocks(W, U, V, 32);
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swap_bytes(W, Key);
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/* encrypt second 8 bytes of H with second key */
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gost_enc_with_key(c, Key, H + 8, S + 8);
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/* compute third key */
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circle_xor8(U, U);
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U[31] = ~U[31];
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U[29] = ~U[29];
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U[28] = ~U[28];
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U[24] = ~U[24];
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U[23] = ~U[23];
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U[20] = ~U[20];
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U[18] = ~U[18];
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U[17] = ~U[17];
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U[14] = ~U[14];
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U[12] = ~U[12];
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U[10] = ~U[10];
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U[8] = ~U[8];
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U[7] = ~U[7];
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U[5] = ~U[5];
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U[3] = ~U[3];
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U[1] = ~U[1];
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circle_xor8(V, V);
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circle_xor8(V, V);
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xor_blocks(W, U, V, 32);
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swap_bytes(W, Key);
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/* encrypt third 8 bytes of H with third key */
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gost_enc_with_key(c, Key, H + 16, S + 16);
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/* Compute fourth key */
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circle_xor8(U, U);
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circle_xor8(V, V);
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circle_xor8(V, V);
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xor_blocks(W, U, V, 32);
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swap_bytes(W, Key);
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/* Encrypt last 8 bytes with fourth key */
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gost_enc_with_key(c, Key, H + 24, S + 24);
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for (i = 0; i < 12; i++)
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transform_3(S);
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xor_blocks(S, S, M, 32);
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transform_3(S);
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xor_blocks(S, S, H, 32);
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for (i = 0; i < 61; i++)
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transform_3(S);
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memcpy(H, S, 32);
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return 1;
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}
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/*
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* Initialize gost_hash ctx - cleans up temporary structures and set up
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* substitution blocks
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*/
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int init_gost_hash_ctx(gost_hash_ctx * ctx,
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const gost_subst_block * subst_block)
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{
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memset(ctx, 0, sizeof(gost_hash_ctx));
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ctx->cipher_ctx = (gost_ctx *) MYALLOC(sizeof(gost_ctx));
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if (!ctx->cipher_ctx) {
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return 0;
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}
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gost_init(ctx->cipher_ctx, subst_block);
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return 1;
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}
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/*
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* Free cipher CTX if it is dynamically allocated. Do not use
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* if cipher ctx is statically allocated as in OpenSSL implementation of
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* GOST hash algroritm
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*
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*/
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void done_gost_hash_ctx(gost_hash_ctx * ctx)
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{
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/*
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* No need to use gost_destroy, because cipher keys are not really secret
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* when hashing
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*/
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MYFREE(ctx->cipher_ctx);
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}
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/*
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* reset state of hash context to begin hashing new message
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*/
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int start_hash(gost_hash_ctx * ctx)
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{
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if (!ctx->cipher_ctx)
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return 0;
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memset(&(ctx->H), 0, 32);
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memset(&(ctx->S), 0, 32);
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ctx->len = 0L;
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ctx->left = 0;
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return 1;
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}
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/*
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* Hash block of arbitrary length
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*
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*
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*/
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int hash_block(gost_hash_ctx * ctx, const byte * block, size_t length)
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{
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if (ctx->left) {
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/*
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* There are some bytes from previous step
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*/
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unsigned int add_bytes = 32 - ctx->left;
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if (add_bytes > length) {
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add_bytes = length;
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}
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memcpy(&(ctx->remainder[ctx->left]), block, add_bytes);
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ctx->left += add_bytes;
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if (ctx->left < 32) {
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return 1;
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}
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block += add_bytes;
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length -= add_bytes;
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hash_step(ctx->cipher_ctx, ctx->H, ctx->remainder);
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add_blocks(32, ctx->S, ctx->remainder);
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ctx->len += 32;
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ctx->left = 0;
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}
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while (length >= 32) {
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hash_step(ctx->cipher_ctx, ctx->H, block);
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add_blocks(32, ctx->S, block);
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ctx->len += 32;
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block += 32;
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length -= 32;
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}
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if (length) {
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memcpy(ctx->remainder, block, ctx->left = length);
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}
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return 1;
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}
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/*
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* Compute hash value from current state of ctx
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* state of hash ctx becomes invalid and cannot be used for further
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* hashing.
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*/
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int finish_hash(gost_hash_ctx * ctx, byte * hashval)
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{
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byte buf[32];
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byte H[32];
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byte S[32];
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ghosthash_len fin_len = ctx->len;
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byte *bptr;
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memcpy(H, ctx->H, 32);
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memcpy(S, ctx->S, 32);
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if (ctx->left) {
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memset(buf, 0, 32);
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memcpy(buf, ctx->remainder, ctx->left);
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hash_step(ctx->cipher_ctx, H, buf);
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add_blocks(32, S, buf);
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fin_len += ctx->left;
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}
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memset(buf, 0, 32);
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bptr = buf;
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fin_len <<= 3; /* Hash length in BITS!! */
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while (fin_len > 0) {
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*(bptr++) = (byte) (fin_len & 0xFF);
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fin_len >>= 8;
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};
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hash_step(ctx->cipher_ctx, H, buf);
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hash_step(ctx->cipher_ctx, H, S);
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memcpy(hashval, H, 32);
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return 1;
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}
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