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Implement double- and triple-DES.
Single-DES is now a special case of triple-DES with all three keys being the same. This is significantly slower than a pure single-DES implementation, but that's fine since nobody should be using it anyway.
This commit is contained in:
Dag-Erling Smørgrav
parent
0c06ab5330
commit
239ab3a471
2 changed files with 77 additions and 15 deletions
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@ -40,7 +40,10 @@ CRYB_BEGIN
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#define DES_BLOCK_LEN 8
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#define des_cipher cryb_des_cipher
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#define des_cipher cryb_des56_cipher
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#define des56_cipher cryb_des56_cipher
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#define des112_cipher cryb_des112_cipher
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#define des268_cipher cryb_des168_cipher
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#define des_ctx cryb_des_ctx
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#define des_init cryb_des_init
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#define des_keystream cryb_des_keystream
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@ -51,7 +54,9 @@ CRYB_BEGIN
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extern cipher_algorithm des_cipher;
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typedef struct {
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uint32_t sk[32];
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uint32_t sk1[32];
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uint32_t sk2[32];
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uint32_t sk3[32];
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} des_ctx;
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void des_init(des_ctx *, cipher_mode mode, const uint8_t *, size_t);
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@ -264,7 +264,7 @@ static const uint32_t rhs[16] = {
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} while (0)
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static void
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des_setkey(uint32_t sk[32], const uint8_t key[8])
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des_setkey(cipher_mode mode, uint32_t sk[32], const uint8_t key[8])
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{
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uint32_t x, y, t;
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unsigned int i;
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@ -295,7 +295,7 @@ des_setkey(uint32_t sk[32], const uint8_t key[8])
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x = (x << 2 | x >> 26) & 0x0FFFFFFF;
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y = (y << 2 | y >> 26) & 0x0FFFFFFF;
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}
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*sk++ =
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sk[i * 2] =
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(x << 4 & 0x24000000) | (x << 28 & 0x10000000) |
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(x << 14 & 0x08000000) | (x << 18 & 0x02080000) |
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(x << 6 & 0x01000000) | (x << 9 & 0x00200000) |
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@ -307,7 +307,7 @@ des_setkey(uint32_t sk[32], const uint8_t key[8])
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(y >> 5 & 0x00000020) | (y >> 10 & 0x00000010) |
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(y >> 3 & 0x00000008) | (y >> 18 & 0x00000004) |
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(y >> 26 & 0x00000002) | (y >> 24 & 0x00000001);
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*sk++ =
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sk[i * 2 + 1] =
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(x << 15 & 0x20000000) | (x << 17 & 0x10000000) |
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(x << 10 & 0x08000000) | (x << 22 & 0x04000000) |
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(x >> 2 & 0x02000000) | (x << 1 & 0x01000000) |
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@ -320,6 +320,12 @@ des_setkey(uint32_t sk[32], const uint8_t key[8])
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(y >> 7 & 0x00000020) | (y >> 3 & 0x00000011) |
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(y << 2 & 0x00000004) | (y >> 21 & 0x00000002);
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}
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if (mode == CIPHER_MODE_DECRYPT) {
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for (i = 0; i < 16; i += 2) {
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SWAP(sk[i + 0], sk[30 - i]);
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SWAP(sk[i + 1], sk[31 - i]);
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}
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}
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}
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/*
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@ -331,10 +337,25 @@ des_crypt_ecb(des_ctx *ctx, const uint8_t input[8], uint8_t output[8])
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uint32_t x, y, t, *sk;
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unsigned int i;
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sk = ctx->sk;
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x = be32dec(input + 0);
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y = be32dec(input + 4);
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sk = ctx->sk1;
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DES_IP(x, y);
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for (i = 0; i < 8; ++i) {
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DES_ROUND(y, x);
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DES_ROUND(x, y);
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}
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DES_FP(y, x);
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SWAP(x, y);
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sk = ctx->sk2;
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DES_IP(x, y);
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for (i = 0; i < 8; ++i) {
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DES_ROUND(y, x);
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DES_ROUND(x, y);
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}
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DES_FP(y, x);
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SWAP(x, y);
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sk = ctx->sk3;
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DES_IP(x, y);
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for (i = 0; i < 8; ++i) {
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DES_ROUND(y, x);
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@ -348,15 +369,29 @@ des_crypt_ecb(des_ctx *ctx, const uint8_t input[8], uint8_t output[8])
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void
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des_init(des_ctx *ctx, cipher_mode mode, const uint8_t *key, size_t keylen)
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{
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unsigned int i;
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cipher_mode m1, m2, m3;
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(void)keylen;
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des_setkey(ctx->sk, key);
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if (mode == CIPHER_MODE_DECRYPT) {
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for (i = 0; i < 16; i += 2) {
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SWAP(ctx->sk[i + 0], ctx->sk[30 - i]);
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SWAP(ctx->sk[i + 1], ctx->sk[31 - i]);
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m1 = m3 = CIPHER_MODE_DECRYPT;
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m2 = CIPHER_MODE_ENCRYPT;
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} else {
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m1 = m3 = CIPHER_MODE_ENCRYPT;
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m2 = CIPHER_MODE_DECRYPT;
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}
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des_setkey(m1, ctx->sk1, key);
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switch (keylen) {
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case 24:
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des_setkey(m2, ctx->sk2, key + 8);
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des_setkey(m3, ctx->sk3, key + 16);
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break;
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case 16:
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des_setkey(m2, ctx->sk2, key + 8);
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des_setkey(m3, ctx->sk3, key);
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break;
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case 8:
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des_setkey(m2, ctx->sk2, key);
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des_setkey(m3, ctx->sk3, key);
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break;
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}
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}
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@ -397,7 +432,7 @@ des_finish(des_ctx *ctx)
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memset_s(ctx, 0, sizeof *ctx, sizeof *ctx);
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}
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cipher_algorithm des_cipher = {
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cipher_algorithm des56_cipher = {
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.name = "des",
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.contextlen = sizeof(des_ctx),
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.blocklen = DES_BLOCK_LEN,
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@ -407,3 +442,25 @@ cipher_algorithm des_cipher = {
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.decrypt = (cipher_decrypt_func)des_decrypt,
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.finish = (cipher_finish_func)des_finish,
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};
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cipher_algorithm des112_cipher = {
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.name = "2des",
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.contextlen = sizeof(des_ctx),
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.blocklen = DES_BLOCK_LEN,
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.keylen = DES_BLOCK_LEN * 2,
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.init = (cipher_init_func)des_init,
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.encrypt = (cipher_encrypt_func)des_encrypt,
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.decrypt = (cipher_decrypt_func)des_decrypt,
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.finish = (cipher_finish_func)des_finish,
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};
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cipher_algorithm des168_cipher = {
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.name = "3des",
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.contextlen = sizeof(des_ctx),
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.blocklen = DES_BLOCK_LEN,
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.keylen = DES_BLOCK_LEN * 3,
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.init = (cipher_init_func)des_init,
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.encrypt = (cipher_encrypt_func)des_encrypt,
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.decrypt = (cipher_decrypt_func)des_decrypt,
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.finish = (cipher_finish_func)des_finish,
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};
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