X-Git-Url: https://git.cryptolib.org/?p=avr-crypto-lib.git;a=blobdiff_plain;f=gcm%2Fgcm128.c;fp=gcm%2Fgcm128.c;h=1f71046228b90c6746767b3b6ab42853dfbaeb0b;hp=0000000000000000000000000000000000000000;hb=e542ff92d053ecf40b42364a44bc887431cecae2;hpb=deca11a7e7be5605c387aa2cd577e22925854ff8

diff --git a/gcm/gcm128.c b/gcm/gcm128.c
new file mode 100644
index 0000000..1f71046
--- /dev/null
+++ b/gcm/gcm128.c
@@ -0,0 +1,331 @@
+/* gcm128.c */
+/*
+    This file is part of the AVR-Crypto-Lib.
+    Copyright (C) 2006-2015 Daniel Otte (daniel.otte@rub.de)
+
+    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 3 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#include <inttypes.h>
+#include <stdlib.h>
+#include <string.h>
+#include <memxor.h>
+#include <blockcipher_descriptor.h>
+#include <bcal-basic.h>
+#include <gcm128.h>
+
+#include <stdio.h>
+#include <cli.h>
+#include <uart.h>
+
+#define DUMP_LEN_LINE(x, len, line) do { \
+        printf("\n\n (DBG <" __FILE__ " %s " #line ">)" #x ":", __func__); \
+        cli_hexdump_block((x), (len), 4, 16); \
+        uart0_flush(); } while (0)
+
+#define DUMP_dummy(x, len, v) DUMP_LEN_LINE(x, len, v)
+#define DUMP_LEN(x, len) DUMP_dummy(x, len, __LINE__)
+
+
+#define DUMP(x) DUMP_LEN(x, sizeof(x))
+
+
+#define BLOCK_BYTES GCM128_BLOCK_BYTES
+#define BLOCK_BITS GCM128_BLOCK_BITS
+
+#define COUNT_BYTES GCM128_COUNT_BYTES
+#define COUNT_BITS GCM128_COUNT_BITS
+
+#define POLY_BYTE 0xE1
+
+
+static uint8_t shift_block_right(void *a)
+{
+    uint8_t c1 = 0, c2;
+    uint8_t i = BLOCK_BYTES;
+    uint8_t *p = a;
+    do {
+        c2 = *p & 1;
+        *p = (*p >> 1) | c1;
+        p++;
+        c1 = c2 ? 0x80 : 0;
+    } while (--i);
+    return c2;
+}
+
+static void gmul128(
+        void *dest,
+        const void *a,
+        const void *b)
+{
+    uint8_t c, v[BLOCK_BYTES], t, dummy[BLOCK_BYTES + 1], *(lut[2]);
+    const uint8_t *x = b;
+    uint8_t i, j;
+    memset(dest, 0, BLOCK_BYTES);
+    memset(dummy, 0, BLOCK_BYTES);
+    dummy[BLOCK_BYTES] = POLY_BYTE;
+    memcpy(v, a, BLOCK_BYTES);
+    lut[0] = dummy;
+    lut[1] = v;
+    i = BLOCK_BYTES;
+    do {
+        j = 8;
+        t = *x++;
+        do {
+            memxor(dest, lut[t >> 7], BLOCK_BYTES);
+            t <<= 1;
+            c = shift_block_right(v);
+            v[0] ^= dummy[15 + c];
+        } while (--j);
+    } while (--i);
+}
+
+static void ghash128_init(ghash128_ctx_t *ctx)
+{
+    memset(ctx->tag, 0, 16);
+}
+
+static void ghash128_block(
+        ghash128_ctx_t *ctx,
+        const void *block)
+{
+    uint8_t tmp[BLOCK_BYTES];
+    memcpy(tmp, ctx->tag, BLOCK_BYTES);
+    memxor(tmp, block, BLOCK_BYTES);
+    gmul128(ctx->tag, tmp, ctx->key);
+}
+
+static void inc32(void *a)
+{
+    uint8_t c, *p = a;
+    c = (p[3]++ == 0);
+    c &= ((p[2] += c) == 0);
+    c &= ((p[1] += c) == 0);
+    p[0] +=c;
+}
+
+int8_t gcm128_init(
+        gcm128_ctx_t *ctx,
+        const bcdesc_t *cipher,
+        const void *key,
+        uint16_t key_length_b,
+        const void *iv,
+        uint16_t iv_length_b)
+{
+    uint8_t r;
+    uint8_t tmp[BLOCK_BYTES];
+    if (bcal_cipher_getBlocksize_b(cipher) != BLOCK_BITS) {
+        return -1;
+    }
+    if ((r = bcal_cipher_init(cipher, key, key_length_b, &ctx->cipher_ctx))) {
+        printf_P(PSTR("Error: return code: %"PRId8" key length: %"PRId16" <%s %s %d>\n"), r, key_length_b, __FILE__, __func__, __LINE__);
+        uart0_flush();
+        return -2;
+    }
+    memset(ctx->ghash_ctx.key, 0, BLOCK_BYTES);
+    bcal_cipher_enc(ctx->ghash_ctx.key, &ctx->cipher_ctx);
+    ghash128_init(&ctx->ghash_ctx);
+    if (iv_length_b == BLOCK_BITS - COUNT_BITS) {
+        memcpy(ctx->ctr, iv, (BLOCK_BITS - COUNT_BITS) / 8);
+        memset(&ctx->ctr[BLOCK_BYTES - COUNT_BYTES], 0, COUNT_BYTES - 1);
+        ctx->ctr[BLOCK_BYTES - 1] = 1;
+    } else {
+        uint16_t ctr = iv_length_b / BLOCK_BITS;
+        while (ctr--)
+        {
+            ghash128_block(&ctx->ghash_ctx, iv);
+            iv = &((uint8_t*)iv)[BLOCK_BYTES];
+        }
+        memset(tmp, 0, BLOCK_BYTES);
+        memcpy(tmp, iv, (iv_length_b % BLOCK_BITS + 7) / 8);
+        if (iv_length_b & 7) {
+            tmp[(iv_length_b % BLOCK_BITS) / 8] &= 0xff << (8 - (iv_length_b & 7));
+        }
+        ghash128_block(&ctx->ghash_ctx, tmp);
+        memset(tmp, 0, BLOCK_BYTES);
+        tmp[BLOCK_BYTES - 2] = iv_length_b >> 8;
+        tmp[BLOCK_BYTES - 1] = iv_length_b & 0xff;
+        ghash128_block(&ctx->ghash_ctx, tmp);
+        memcpy(ctx->ctr, ctx->ghash_ctx.tag, BLOCK_BYTES);
+        ghash128_init(&ctx->ghash_ctx);
+    }
+    memcpy(ctx->j0, &ctx->ctr[BLOCK_BYTES - COUNT_BYTES], COUNT_BYTES);
+    ctx->length_a = 0;
+    ctx->length_c = 0;
+    return 0;
+}
+
+void gcm128_add_ad_block(
+        gcm128_ctx_t *ctx,
+        const void *block )
+{
+    ghash128_block(&ctx->ghash_ctx, block);
+    ctx->length_a += BLOCK_BITS;
+}
+
+void gcm128_add_ad_final_block(
+        gcm128_ctx_t *ctx,
+        const void *block,
+        uint16_t length_b )
+{
+    uint8_t tmp[BLOCK_BYTES];
+    while (length_b >= BLOCK_BITS)
+    {
+        gcm128_add_ad_block(ctx, block);
+        length_b -= BLOCK_BITS;
+        block = &((uint8_t*)block)[BLOCK_BYTES];
+    }
+    if (length_b > 0) {
+        memset(tmp, 0, BLOCK_BYTES);
+        memcpy(tmp, block, (length_b + 7) / 8);
+        if (length_b & 7) {
+            tmp[length_b / 8] &= 0xff << (8 - (length_b & 7));
+        }
+        ghash128_block(&ctx->ghash_ctx, tmp);
+        ctx->length_a += length_b;
+    }
+}
+
+void gcm128_encrypt_block(
+        gcm128_ctx_t *ctx,
+        void *dest,
+        const void *src)
+{
+    uint8_t tmp[BLOCK_BYTES];
+    inc32(&ctx->ctr[BLOCK_BYTES - COUNT_BYTES]);
+    memcpy(tmp, ctx->ctr, BLOCK_BYTES);
+    bcal_cipher_enc(tmp, &ctx->cipher_ctx);
+    memxor(tmp, src, BLOCK_BYTES);
+    ghash128_block(&ctx->ghash_ctx, tmp);
+    ctx->length_c += BLOCK_BITS;
+    if (dest) {
+        memcpy(dest, tmp, BLOCK_BYTES);
+    }
+}
+
+void gcm128_encrypt_final_block(
+        gcm128_ctx_t *ctx,
+        void *dest,
+        const void *src,
+        uint16_t length_b
+        )
+{
+    uint8_t tmp[BLOCK_BYTES];
+    while (length_b >= BLOCK_BITS) {
+        gcm128_encrypt_block(ctx, dest, src);
+        length_b -= BLOCK_BITS;
+        if (dest) {
+            dest = &((uint8_t*)dest)[BLOCK_BYTES];
+        }
+        src = &((uint8_t*)src)[BLOCK_BYTES];
+    }
+    if (length_b > 0) {
+        inc32(&ctx->ctr[BLOCK_BYTES - COUNT_BYTES]);
+        memcpy(tmp, ctx->ctr, BLOCK_BYTES);
+        bcal_cipher_enc(tmp, &ctx->cipher_ctx);
+        memxor(tmp, src, BLOCK_BYTES);
+        memset(&tmp[(length_b + 7) / 8], 0, BLOCK_BYTES - (length_b + 7) / 8);
+        if (length_b & 7) {
+            tmp[length_b / 8] &= 0xff << (8 - (length_b & 7));
+        }
+        ghash128_block(&ctx->ghash_ctx, tmp);
+        ctx->length_c += length_b;
+        if (dest) {
+            memcpy(dest, tmp, (length_b + 7) / 8);
+        }
+    }
+}
+
+void gcm128_decrypt_block(
+        gcm128_ctx_t *ctx,
+        void *dest,
+        const void *src)
+{
+    uint8_t tmp[BLOCK_BYTES];
+    ghash128_block(&ctx->ghash_ctx, src);
+    inc32(&ctx->ctr[11]);
+    memcpy(tmp, ctx->ctr, BLOCK_BYTES);
+    bcal_cipher_enc(tmp, &ctx->cipher_ctx);
+    memxor(tmp, src, BLOCK_BYTES);
+    ctx->length_c += BLOCK_BITS;
+    if (dest) {
+        memcpy(dest, tmp, BLOCK_BYTES);
+    }
+}
+
+void gcm128_decrypt_final_block(
+        gcm128_ctx_t *ctx,
+        void *dest,
+        const void *src,
+        uint16_t length_b)
+{
+    uint8_t tmp[BLOCK_BYTES];
+    while (length_b > BLOCK_BITS) {
+        gcm128_decrypt_block(ctx, dest, src);
+        length_b -= BLOCK_BITS;
+        if (dest) {
+            dest = &((uint8_t*)dest)[BLOCK_BYTES];
+        }
+        src = &((uint8_t*)src)[BLOCK_BYTES];
+    }
+    if (length_b > 0) {
+        memcpy(tmp, src, (length_b + 7) / 8);
+        memset(&tmp[(length_b + 7) / 8], 0, BLOCK_BYTES - (length_b + 7) / 8);
+        if (length_b & 7) {
+            tmp[length_b / 8] &= 0xff << (8 - (length_b & 7));
+        }
+        ghash128_block(&ctx->ghash_ctx, tmp);
+        inc32(&ctx->ctr[11]);
+        memcpy(tmp, ctx->ctr, BLOCK_BYTES);
+        bcal_cipher_enc(tmp, &ctx->cipher_ctx);
+        memxor(tmp, src, BLOCK_BYTES);
+        memset(&tmp[(length_b + 7) / 8], 0, BLOCK_BYTES - (length_b + 7) / 8);
+        if (length_b & 7) {
+            tmp[length_b / 8] &= 0xff << (8 - (length_b & 7));
+        }
+        ctx->length_c += length_b;
+        if (dest) {
+            memcpy(dest, tmp, (length_b + 7) / 8);
+        }
+    }
+}
+
+void gcm128_finalize(gcm128_ctx_t *ctx, void *tag, uint16_t tag_length_b)
+{
+    uint8_t tmp[BLOCK_BYTES];
+    memset(tmp, 0, BLOCK_BYTES);
+    tmp[4] = ctx->length_a >> 24;
+    tmp[5] = ctx->length_a >> 16;
+    tmp[6] = ctx->length_a >>  8;
+    tmp[7] = ctx->length_a;
+    tmp[12] = ctx->length_c >> 24;
+    tmp[13] = ctx->length_c >> 16;
+    tmp[14] = ctx->length_c >>  8;
+    tmp[15] = ctx->length_c;
+    ghash128_block(&ctx->ghash_ctx, tmp);
+    memcpy(tmp, ctx->ctr, BLOCK_BYTES - COUNT_BYTES);
+    memcpy(&tmp[BLOCK_BYTES - COUNT_BYTES], ctx->j0, COUNT_BYTES);
+    bcal_cipher_enc(tmp, &ctx->cipher_ctx);
+    bcal_cipher_free(&ctx->cipher_ctx);
+    memxor(tmp, ctx->ghash_ctx.tag, BLOCK_BYTES);
+    if (tag_length_b > BLOCK_BITS) {
+        tag_length_b = BLOCK_BITS;
+    }
+    if (tag_length_b & 7) {
+        tmp[tag_length_b / 8] &= 0xff << (8 - (tag_length_b & 7));
+    }
+    if (tag) {
+        memcpy(tag, tmp, (tag_length_b + 7) / 8);
+    }
+}