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.

include/cryb/des.h

@@ -40,7 +40,10 @@ CRYB_BEGIN
 
 #define DES_BLOCK_LEN			8
 
-#define des_cipher			cryb_des_cipher
+#define des_cipher			cryb_des56_cipher
+#define des56_cipher			cryb_des56_cipher
+#define des112_cipher			cryb_des112_cipher
+#define des268_cipher			cryb_des168_cipher
 #define des_ctx				cryb_des_ctx
 #define des_init			cryb_des_init
 #define des_keystream			cryb_des_keystream
@@ -51,7 +54,9 @@ CRYB_BEGIN
 extern cipher_algorithm des_cipher;
 
 typedef struct {
-	uint32_t sk[32];
+	uint32_t sk1[32];
+	uint32_t sk2[32];
+	uint32_t sk3[32];
 } des_ctx;
 
 void des_init(des_ctx *, cipher_mode mode, const uint8_t *, size_t);

lib/cipher/cryb_des.c

@@ -264,7 +264,7 @@ static const uint32_t rhs[16] = {
 	} while (0)
 
 static void
-des_setkey(uint32_t sk[32], const uint8_t key[8])
+des_setkey(cipher_mode mode, uint32_t sk[32], const uint8_t key[8])
 {
 	uint32_t x, y, t;
 	unsigned int i;
@@ -295,7 +295,7 @@ des_setkey(uint32_t sk[32], const uint8_t key[8])
 			x = (x <<  2 | x >> 26) & 0x0FFFFFFF;
 			y = (y <<  2 | y >> 26) & 0x0FFFFFFF;
 		}
-		*sk++ =
+		sk[i * 2] =
 		    (x <<  4 & 0x24000000) | (x << 28 & 0x10000000) |
 		    (x << 14 & 0x08000000) | (x << 18 & 0x02080000) |
 		    (x <<  6 & 0x01000000) | (x <<  9 & 0x00200000) |
@@ -307,7 +307,7 @@ des_setkey(uint32_t sk[32], const uint8_t key[8])
 		    (y >>  5 & 0x00000020) | (y >> 10 & 0x00000010) |
 		    (y >>  3 & 0x00000008) | (y >> 18 & 0x00000004) |
 		    (y >> 26 & 0x00000002) | (y >> 24 & 0x00000001);
-		*sk++ =
+		sk[i * 2 + 1] =
 		    (x << 15 & 0x20000000) | (x << 17 & 0x10000000) |
 		    (x << 10 & 0x08000000) | (x << 22 & 0x04000000) |
 		    (x >>  2 & 0x02000000) | (x <<  1 & 0x01000000) |
@@ -320,6 +320,12 @@ des_setkey(uint32_t sk[32], const uint8_t key[8])
 		    (y >>  7 & 0x00000020) | (y >>  3 & 0x00000011) |
 		    (y <<  2 & 0x00000004) | (y >> 21 & 0x00000002);
 	}
+	if (mode == CIPHER_MODE_DECRYPT) {
+		for (i = 0; i < 16; i += 2) {
+			SWAP(sk[i + 0], sk[30 - i]);
+			SWAP(sk[i + 1], sk[31 - i]);
+		}
+	}
 }
 
 /*
@@ -331,10 +337,25 @@ des_crypt_ecb(des_ctx *ctx, const uint8_t input[8], uint8_t output[8])
 	uint32_t x, y, t, *sk;
 	unsigned int i;
 
-	sk = ctx->sk;
-
 	x = be32dec(input + 0);
 	y = be32dec(input + 4);
+	sk = ctx->sk1;
+	DES_IP(x, y);
+	for (i = 0; i < 8; ++i) {
+		DES_ROUND(y, x);
+		DES_ROUND(x, y);
+	}
+	DES_FP(y, x);
+	SWAP(x, y);
+	sk = ctx->sk2;
+	DES_IP(x, y);
+	for (i = 0; i < 8; ++i) {
+		DES_ROUND(y, x);
+		DES_ROUND(x, y);
+	}
+	DES_FP(y, x);
+	SWAP(x, y);
+	sk = ctx->sk3;
 	DES_IP(x, y);
 	for (i = 0; i < 8; ++i) {
 		DES_ROUND(y, x);
@@ -348,15 +369,29 @@ des_crypt_ecb(des_ctx *ctx, const uint8_t input[8], uint8_t output[8])
 void
 des_init(des_ctx *ctx, cipher_mode mode, const uint8_t *key, size_t keylen)
 {
-	unsigned int i;
+	cipher_mode m1, m2, m3;
 
-	(void)keylen;
-	des_setkey(ctx->sk, key);
 	if (mode == CIPHER_MODE_DECRYPT) {
-		for (i = 0; i < 16; i += 2) {
+		m1 = m3 = CIPHER_MODE_DECRYPT;
-			SWAP(ctx->sk[i + 0], ctx->sk[30 - i]);
+		m2 = CIPHER_MODE_ENCRYPT;
-			SWAP(ctx->sk[i + 1], ctx->sk[31 - i]);
+	} else {
+		m1 = m3 = CIPHER_MODE_ENCRYPT;
+		m2 = CIPHER_MODE_DECRYPT;
 	}
+	des_setkey(m1, ctx->sk1, key);
+	switch (keylen) {
+	case 24:
+		des_setkey(m2, ctx->sk2, key + 8);
+		des_setkey(m3, ctx->sk3, key + 16);
+		break;
+	case 16:
+		des_setkey(m2, ctx->sk2, key + 8);
+		des_setkey(m3, ctx->sk3, key);
+		break;
+	case 8:
+		des_setkey(m2, ctx->sk2, key);
+		des_setkey(m3, ctx->sk3, key);
+		break;
 	}
 }
 
@@ -397,7 +432,7 @@ des_finish(des_ctx *ctx)
 	memset_s(ctx, 0, sizeof *ctx, sizeof *ctx);
 }
 
-cipher_algorithm des_cipher = {
+cipher_algorithm des56_cipher = {
 	.name			 = "des",
 	.contextlen		 = sizeof(des_ctx),
 	.blocklen		 = DES_BLOCK_LEN,
@@ -407,3 +442,25 @@ cipher_algorithm des_cipher = {
 	.decrypt		 = (cipher_decrypt_func)des_decrypt,
 	.finish			 = (cipher_finish_func)des_finish,
 };
+
+cipher_algorithm des112_cipher = {
+	.name			 = "2des",
+	.contextlen		 = sizeof(des_ctx),
+	.blocklen		 = DES_BLOCK_LEN,
+	.keylen			 = DES_BLOCK_LEN * 2,
+	.init			 = (cipher_init_func)des_init,
+	.encrypt		 = (cipher_encrypt_func)des_encrypt,
+	.decrypt		 = (cipher_decrypt_func)des_decrypt,
+	.finish			 = (cipher_finish_func)des_finish,
+};
+
+cipher_algorithm des168_cipher = {
+	.name			 = "3des",
+	.contextlen		 = sizeof(des_ctx),
+	.blocklen		 = DES_BLOCK_LEN,
+	.keylen			 = DES_BLOCK_LEN * 3,
+	.init			 = (cipher_init_func)des_init,
+	.encrypt		 = (cipher_encrypt_func)des_encrypt,
+	.decrypt		 = (cipher_decrypt_func)des_decrypt,
+	.finish			 = (cipher_finish_func)des_finish,
+};