Diff: wolfcrypt/src/idea.c

Revision:

7:481bce714567

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/wolfcrypt/src/idea.c	Tue May 02 08:44:47 2017 +0000
@@ -0,0 +1,288 @@
+/* idea.c
+ *
+ * Copyright (C) 2006-2016 wolfSSL Inc.
+ *
+ * This file is part of wolfSSL.
+ *
+ * wolfSSL 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 2 of the License, or
+ * (at your option) any later version.
+ *
+ * wolfSSL 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, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1335, USA
+ */
+
+
+#ifdef HAVE_CONFIG_H
+    #include <config.h>
+#endif
+
+#include <wolfssl/wolfcrypt/settings.h>
+
+#ifdef HAVE_IDEA
+
+#include <wolfssl/wolfcrypt/idea.h>
+
+#include <wolfssl/wolfcrypt/error-crypt.h>
+#include <wolfssl/wolfcrypt/logging.h>
+
+#ifdef NO_INLINE
+    #include <wolfssl/wolfcrypt/misc.h>
+#else
+    #define WOLFSSL_MISC_INCLUDED
+    #include <wolfcrypt/src/misc.c>
+#endif
+
+/* multiplication of x and y modulo 2^16+1
+ * IDEA specify a special case when an entry value is 0 ( x or y)
+ * then it must be replaced by 2^16
+ */
+static INLINE word16 idea_mult(word16 x, word16 y)
+{
+    long mul, res;
+
+    mul = (long)x * (long)y;
+    if (mul) {
+        res = (mul & IDEA_MASK) - ((word32)mul >> 16);
+        if (res <= 0)
+            res += IDEA_MODULO;
+
+        return (word16) (res & IDEA_MASK);
+    }
+
+    if (!x)
+        return ((IDEA_MODULO - y) & IDEA_MASK);
+
+    /* !y */
+    return ((IDEA_MODULO - x) & IDEA_MASK);
+}
+
+/* compute 1/a modulo 2^16+1 using Extended euclidean algorithm
+ * adapted from fp_invmod */
+static INLINE word16 idea_invmod(word16 x)
+{
+    int   u, v, b, d;
+
+    if (x <= 1)
+        return x;
+
+    u = IDEA_MODULO;
+    v = x;
+    d = 1;
+    b = 0;
+
+    do {
+        while (!(u & 1)) {
+            u >>= 1;
+            if (b & 1)
+                b -= IDEA_MODULO;
+            b >>= 1;
+        }
+
+        while (!(v & 1)) {
+            v >>= 1;
+            if (d & 1) {
+                d -= IDEA_MODULO;
+            }
+            d >>= 1;
+        }
+
+        if (u >= v) {
+            u -= v;
+            b -= d;
+        } else {
+            v -= u;
+            d -= b;
+        }
+    } while (u != 0);
+
+    /* d is now the inverse, put positive value if required */
+    while (d < 0)
+        d += IDEA_MODULO;
+
+    /* d must be < IDEA_MODULO */
+    while (d >= (int)IDEA_MODULO)
+        d -= IDEA_MODULO;
+
+    return (word16)(d & IDEA_MASK);
+}
+
+/* generate the 52 16-bits key sub-blocks from the 128 key */
+int wc_IdeaSetKey(Idea *idea, const byte* key, word16 keySz,
+                  const byte *iv, int dir)
+{
+    word16  idx = 0;
+    word32  t;
+    short   i;
+
+    if (idea == NULL || key == NULL || keySz != IDEA_KEY_SIZE ||
+        (dir != IDEA_ENCRYPTION && dir != IDEA_DECRYPTION))
+        return BAD_FUNC_ARG;
+
+    /* initial key schedule for 0 -> 7 */
+    for (i = 0; i < IDEA_ROUNDS; i++) {
+        idea->skey[i]  = (word16)key[idx++] << 8;
+        idea->skey[i] |= (word16)key[idx++];
+    }
+
+    /* shift phase key schedule for 8 -> 51 */
+    for (i = IDEA_ROUNDS; i < IDEA_SK_NUM; i++) {
+        t  = (word32)idea->skey[((i+1) & 7) ? i-7 : i-15] << 9;
+        t |= (word32)idea->skey[((i+2) & 7) < 2 ? i-14 : i-6] >> 7;
+        idea->skey[i] = (word16)(t & IDEA_MASK);
+    }
+
+    /* compute decryption key from encryption key */
+    if (dir == IDEA_DECRYPTION) {
+        word16  enckey[IDEA_SK_NUM];
+
+        /* put encryption key in tmp buffer */
+        XMEMCPY(enckey, idea->skey, sizeof(idea->skey));
+
+        idx = 0;
+
+        idea->skey[6*IDEA_ROUNDS]   = idea_invmod(enckey[idx++]);
+        idea->skey[6*IDEA_ROUNDS+1] = (IDEA_2EXP16 - enckey[idx++]) & IDEA_MASK;
+        idea->skey[6*IDEA_ROUNDS+2] = (IDEA_2EXP16 - enckey[idx++]) & IDEA_MASK;
+        idea->skey[6*IDEA_ROUNDS+3] = idea_invmod(enckey[idx++]);
+
+        for (i = 6*(IDEA_ROUNDS-1); i >= 0; i -= 6) {
+            idea->skey[i+4] = enckey[idx++];
+            idea->skey[i+5] = enckey[idx++];
+
+            idea->skey[i] = idea_invmod(enckey[idx++]);
+            if (i) {
+                idea->skey[i+2] = (IDEA_2EXP16 - enckey[idx++]) & IDEA_MASK;
+                idea->skey[i+1] = (IDEA_2EXP16 - enckey[idx++]) & IDEA_MASK;
+            }
+            else {
+                idea->skey[1] = (IDEA_2EXP16 - enckey[idx++]) & IDEA_MASK;
+                idea->skey[2] = (IDEA_2EXP16 - enckey[idx++]) & IDEA_MASK;
+            }
+
+            idea->skey[i+3] = idea_invmod(enckey[idx++]);
+        }
+
+        /* erase temporary buffer */
+        ForceZero(enckey, sizeof(enckey));
+    }
+
+    /* set the iv */
+    return wc_IdeaSetIV(idea, iv);
+}
+
+/* set the IV in the Idea key structure */
+int wc_IdeaSetIV(Idea *idea, const byte* iv)
+{
+    if (idea == NULL)
+        return BAD_FUNC_ARG;
+
+    if (iv != NULL)
+        XMEMCPY(idea->reg, iv, IDEA_BLOCK_SIZE);
+    else
+        XMEMSET(idea->reg, 0, IDEA_BLOCK_SIZE);
+
+    return 0;
+}
+
+/* encryption/decryption for a block (64 bits)
+ */
+void wc_IdeaCipher(Idea *idea, byte* out, const byte* in)
+{
+    word32 t1, t2;
+    word16 i, skey_idx = 0, idx = 0;
+    word16 x[4];
+
+    /* put input byte block in word16 */
+    for (i = 0; i < IDEA_BLOCK_SIZE/2; i++) {
+        x[i]  = (word16)in[idx++] << 8;
+        x[i] |= (word16)in[idx++];
+    }
+
+    for (i = 0; i < IDEA_ROUNDS; i++) {
+        x[0] = idea_mult(x[0], idea->skey[skey_idx++]);
+        x[1] = ((word32)x[1] + (word32)idea->skey[skey_idx++]) & IDEA_MASK;
+        x[2] = ((word32)x[2] + (word32)idea->skey[skey_idx++]) & IDEA_MASK;
+        x[3] = idea_mult(x[3], idea->skey[skey_idx++]);
+
+        t2 = x[0] ^ x[2];
+        t2 = idea_mult((word16)t2, idea->skey[skey_idx++]);
+        t1 = (t2 + (x[1] ^ x[3])) & IDEA_MASK;
+        t1 = idea_mult((word16)t1, idea->skey[skey_idx++]);
+        t2 = (t1 + t2) & IDEA_MASK;
+
+        x[0] ^= t1;
+        x[3] ^= t2;
+
+        t2 ^= x[1];
+        x[1] = x[2] ^ (word16)t1;
+        x[2] = (word16)t2;
+    }
+
+    x[0] = idea_mult(x[0], idea->skey[skey_idx++]);
+    out[0] = (x[0] >> 8) & 0xFF;
+    out[1] = x[0] & 0xFF;
+
+    x[2] = ((word32)x[2] + (word32)idea->skey[skey_idx++]) & IDEA_MASK;
+    out[2] = (x[2] >> 8) & 0xFF;
+    out[3] = x[2] & 0xFF;
+
+    x[1] = ((word32)x[1] + (word32)idea->skey[skey_idx++]) & IDEA_MASK;
+    out[4] = (x[1] >> 8) & 0xFF;
+    out[5] = x[1] & 0xFF;
+
+    x[3] = idea_mult(x[3], idea->skey[skey_idx++]);
+    out[6] = (x[3] >> 8) & 0xFF;
+    out[7] = x[3] & 0xFF;
+}
+
+int wc_IdeaCbcEncrypt(Idea *idea, byte* out, const byte* in, word32 len)
+{
+    int  blocks;
+
+    if (idea == NULL || out == NULL || in == NULL)
+        return BAD_FUNC_ARG;
+
+    blocks = len / IDEA_BLOCK_SIZE;
+    while (blocks--) {
+        xorbuf((byte*)idea->reg, in, IDEA_BLOCK_SIZE);
+        wc_IdeaCipher(idea, (byte*)idea->reg, (byte*)idea->reg);
+        XMEMCPY(out, idea->reg, IDEA_BLOCK_SIZE);
+
+        out += IDEA_BLOCK_SIZE;
+        in  += IDEA_BLOCK_SIZE;
+    }
+
+    return 0;
+}
+
+int wc_IdeaCbcDecrypt(Idea *idea, byte* out, const byte* in, word32 len)
+{
+    int  blocks;
+
+    if (idea == NULL || out == NULL || in == NULL)
+        return BAD_FUNC_ARG;
+
+    blocks = len / IDEA_BLOCK_SIZE;
+    while (blocks--) {
+        XMEMCPY((byte*)idea->tmp, in, IDEA_BLOCK_SIZE);
+        wc_IdeaCipher(idea, out, (byte*)idea->tmp);
+        xorbuf(out, (byte*)idea->reg, IDEA_BLOCK_SIZE);
+        XMEMCPY(idea->reg, idea->tmp, IDEA_BLOCK_SIZE);
+
+        out += IDEA_BLOCK_SIZE;
+        in  += IDEA_BLOCK_SIZE;
+    }
+
+    return 0;
+}
+
+#endif /* HAVE_IDEA */
+