From 7d84936fd7382b59379c4663f36dd3bcbea5c875 Mon Sep 17 00:00:00 2001
From: Christian Mehlis <mehlis@inf.fu-berlin.de>
Date: Tue, 6 Aug 2013 18:52:30 +0200
Subject: [PATCH] add sha256 implementation

---
 sys/Makefile         |   3 +
 sys/crypto/Makefile  |   5 +
 sys/crypto/sha256.c  | 269 +++++++++++++++++++++++++++++++++++++++++++
 sys/include/sha256.h |  47 ++++++++
 4 files changed, 324 insertions(+)
 create mode 100644 sys/crypto/Makefile
 create mode 100644 sys/crypto/sha256.c
 create mode 100644 sys/include/sha256.h

diff --git a/sys/Makefile b/sys/Makefile
index 66bbdbe6bd..292e70b3e2 100644
--- a/sys/Makefile
+++ b/sys/Makefile
@@ -85,6 +85,9 @@ endif
 ifneq (,$(findstring bloom,$(USEMODULE)))
     DIRS += bloom
 endif
+ifneq (,$(findstring crypto,$(USEMODULE)))
+    DIRS += crypto
+endif
 
 all: $(BINDIR)$(MODULE).a 
 	@for i in $(DIRS) ; do $(MAKE) -C $$i ; done ;
diff --git a/sys/crypto/Makefile b/sys/crypto/Makefile
new file mode 100644
index 0000000000..daeb4a17fd
--- /dev/null
+++ b/sys/crypto/Makefile
@@ -0,0 +1,5 @@
+INCLUDES = -I../include
+MODULE = crypto
+
+include $(RIOTBASE)/Makefile.base
+
diff --git a/sys/crypto/sha256.c b/sys/crypto/sha256.c
new file mode 100644
index 0000000000..098bf649e5
--- /dev/null
+++ b/sys/crypto/sha256.c
@@ -0,0 +1,269 @@
+/*-
+ * Copyright 2005 Colin Percival
+ * Copyright 2013 Christian Mehlis & René Kijewski
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ * $FreeBSD: src/lib/libmd/sha256c.c,v 1.2 2006/01/17 15:35:56 phk Exp $
+ */
+
+#include <string.h>
+
+#include "sha256.h"
+
+#if __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
+/* Copy a vector of big-endian uint32_t into a vector of bytes */
+#define be32enc_vect(dst, src, len) \
+    memcpy((void *)dst, (const void *)src, (size_t)len)
+
+/* Copy a vector of bytes into a vector of big-endian uint32_t */
+#define be32dec_vect(dst, src, len) \
+    memcpy((void *)dst, (const void *)src, (size_t)len)
+
+#else /* __BYTE_ORDER__ != __ORDER_BIG_ENDIAN__ */
+
+static void be32enc(void *pp, uint32_t u)
+{
+    unsigned char *p = (unsigned char *) pp;
+
+    p[0] = (u >> 24) & 0xff;
+    p[1] = (u >> 16) & 0xff;
+    p[2] = (u >> 8) & 0xff;
+    p[3] = u & 0xff;
+}
+
+static uint32_t be32dec(const void *pp)
+{
+    unsigned char const *p = (unsigned char const *) pp;
+
+    return ((p[0] << 24) | (p[1] << 16) | (p[2] << 8) | p[3]);
+}
+
+/*
+ * Encode a length len/4 vector of (uint32_t) into a length len vector of
+ * (unsigned char) in big-endian form.  Assumes len is a multiple of 4.
+ */
+static void be32enc_vect(unsigned char *dst, const uint32_t *src, size_t len)
+{
+    size_t i;
+
+    for (i = 0; i < len / 4; i++) {
+        be32enc(dst + i * 4, src[i]);
+    }
+}
+
+/*
+ * Decode a big-endian length len vector of (unsigned char) into a length
+ * len/4 vector of (uint32_t).  Assumes len is a multiple of 4.
+ */
+static void be32dec_vect(uint32_t *dst, const unsigned char *src, size_t len)
+{
+    size_t i;
+
+    for (i = 0; i < len / 4; i++) {
+        dst[i] = be32dec(src + i * 4);
+    }
+}
+
+#endif /* __BYTE_ORDER__ != __ORDER_BIG_ENDIAN__ */
+
+/* Elementary functions used by SHA256 */
+#define Ch(x, y, z) ((x & (y ^ z)) ^ z)
+#define Maj(x, y, z)    ((x & (y | z)) | (y & z))
+#define SHR(x, n)   (x >> n)
+#define ROTR(x, n)  ((x >> n) | (x << (32 - n)))
+#define S0(x)       (ROTR(x, 2) ^ ROTR(x, 13) ^ ROTR(x, 22))
+#define S1(x)       (ROTR(x, 6) ^ ROTR(x, 11) ^ ROTR(x, 25))
+#define s0(x)       (ROTR(x, 7) ^ ROTR(x, 18) ^ SHR(x, 3))
+#define s1(x)       (ROTR(x, 17) ^ ROTR(x, 19) ^ SHR(x, 10))
+
+/* SHA256 round function */
+#define RND(a, b, c, d, e, f, g, h, k)          \
+    t0 = h + S1(e) + Ch(e, f, g) + k;       \
+    t1 = S0(a) + Maj(a, b, c);          \
+    d += t0;                    \
+    h  = t0 + t1;
+
+/* Adjusted round function for rotating state */
+#define RNDr(S, W, i, k)            \
+    RND(S[(64 - i) % 8], S[(65 - i) % 8],   \
+        S[(66 - i) % 8], S[(67 - i) % 8],   \
+        S[(68 - i) % 8], S[(69 - i) % 8],   \
+        S[(70 - i) % 8], S[(71 - i) % 8],   \
+        W[i] + k)
+
+static const uint32_t ks[64] = {
+    0x428a2f98, 0x71374491, 0xb5c0fbcf, 0xe9b5dba5,
+    0x3956c25b, 0x59f111f1, 0x923f82a4, 0xab1c5ed5,
+    0xd807aa98, 0x12835b01, 0x243185be, 0x550c7dc3,
+    0x72be5d74, 0x80deb1fe, 0x9bdc06a7, 0xc19bf174,
+    0xe49b69c1, 0xefbe4786, 0x0fc19dc6, 0x240ca1cc,
+    0x2de92c6f, 0x4a7484aa, 0x5cb0a9dc, 0x76f988da,
+    0x983e5152, 0xa831c66d, 0xb00327c8, 0xbf597fc7,
+    0xc6e00bf3, 0xd5a79147, 0x06ca6351, 0x14292967,
+    0x27b70a85, 0x2e1b2138, 0x4d2c6dfc, 0x53380d13,
+    0x650a7354, 0x766a0abb, 0x81c2c92e, 0x92722c85,
+    0xa2bfe8a1, 0xa81a664b, 0xc24b8b70, 0xc76c51a3,
+    0xd192e819, 0xd6990624, 0xf40e3585, 0x106aa070,
+    0x19a4c116, 0x1e376c08, 0x2748774c, 0x34b0bcb5,
+    0x391c0cb3, 0x4ed8aa4a, 0x5b9cca4f, 0x682e6ff3,
+    0x748f82ee, 0x78a5636f, 0x84c87814, 0x8cc70208,
+    0x90befffa, 0xa4506ceb, 0xbef9a3f7, 0xc67178f2,
+};
+
+/*
+ * SHA256 block compression function.  The 256-bit state is transformed via
+ * the 512-bit input block to produce a new state.
+ */
+static void SHA256_Transform(uint32_t *state, const unsigned char block[64])
+{
+    uint32_t W[64];
+    uint32_t S[8];
+    uint32_t t0, t1;
+    int i;
+
+    /* 1. Prepare message schedule W. */
+    be32dec_vect(W, block, 64);
+
+    for (i = 16; i < 64; i++) {
+        W[i] = s1(W[i - 2]) + W[i - 7] + s0(W[i - 15]) + W[i - 16];
+    }
+
+    /* 2. Initialize working variables. */
+    memcpy(S, state, 32);
+
+    /* 3. Mix. */
+    for (i = 0; i < 64; ++i) {
+        RNDr(S, W, i, ks[i]);
+    }
+
+    /* 4. Mix local working variables into global state */
+    for (i = 0; i < 8; i++) {
+        state[i] += S[i];
+    }
+}
+
+static unsigned char PAD[64] = { 0x80, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+        0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+        0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+        0 };
+
+/* Add padding and terminating bit-count. */
+static void SHA256_Pad(SHA256_CTX *ctx)
+{
+    unsigned char len[8];
+    uint32_t r, plen;
+
+    /*
+     * Convert length to a vector of bytes -- we do this now rather
+     * than later because the length will change after we pad.
+     */
+    be32enc_vect(len, ctx->count, 8);
+
+    /* Add 1--64 bytes so that the resulting length is 56 mod 64 */
+    r = (ctx->count[1] >> 3) & 0x3f;
+    plen = (r < 56) ? (56 - r) : (120 - r);
+    SHA256_Update(ctx, PAD, (size_t) plen);
+
+    /* Add the terminating bit-count */
+    SHA256_Update(ctx, len, 8);
+}
+
+/* SHA-256 initialization.  Begins a SHA-256 operation. */
+void SHA256_Init(SHA256_CTX *ctx)
+{
+
+    /* Zero bits processed so far */
+    ctx->count[0] = ctx->count[1] = 0;
+
+    /* Magic initialization constants */
+    ctx->state[0] = 0x6A09E667;
+    ctx->state[1] = 0xBB67AE85;
+    ctx->state[2] = 0x3C6EF372;
+    ctx->state[3] = 0xA54FF53A;
+    ctx->state[4] = 0x510E527F;
+    ctx->state[5] = 0x9B05688C;
+    ctx->state[6] = 0x1F83D9AB;
+    ctx->state[7] = 0x5BE0CD19;
+}
+
+/* Add bytes into the hash */
+void SHA256_Update(SHA256_CTX *ctx, const void *in, size_t len)
+{
+    uint32_t bitlen[2];
+    uint32_t r;
+    const unsigned char *src = in;
+
+    /* Number of bytes left in the buffer from previous updates */
+    r = (ctx->count[1] >> 3) & 0x3f;
+
+    /* Convert the length into a number of bits */
+    bitlen[1] = ((uint32_t) len) << 3;
+    bitlen[0] = (uint32_t)(len >> 29);
+
+    /* Update number of bits */
+    if ((ctx->count[1] += bitlen[1]) < bitlen[1]) {
+        ctx->count[0]++;
+    }
+
+    ctx->count[0] += bitlen[0];
+
+    /* Handle the case where we don't need to perform any transforms */
+    if (len < 64 - r) {
+        memcpy(&ctx->buf[r], src, len);
+        return;
+    }
+
+    /* Finish the current block */
+    memcpy(&ctx->buf[r], src, 64 - r);
+    SHA256_Transform(ctx->state, ctx->buf);
+    src += 64 - r;
+    len -= 64 - r;
+
+    /* Perform complete blocks */
+    while (len >= 64) {
+        SHA256_Transform(ctx->state, src);
+        src += 64;
+        len -= 64;
+    }
+
+    /* Copy left over data into buffer */
+    memcpy(ctx->buf, src, len);
+}
+
+/*
+ * SHA-256 finalization.  Pads the input data, exports the hash value,
+ * and clears the context state.
+ */
+void SHA256_Final(unsigned char digest[32], SHA256_CTX *ctx)
+{
+
+    /* Add padding */
+    SHA256_Pad(ctx);
+
+    /* Write the hash */
+    be32enc_vect(digest, ctx->state, 32);
+
+    /* Clear the context state */
+    memset((void *) ctx, 0, sizeof(*ctx));
+}
diff --git a/sys/include/sha256.h b/sys/include/sha256.h
new file mode 100644
index 0000000000..a65f342c69
--- /dev/null
+++ b/sys/include/sha256.h
@@ -0,0 +1,47 @@
+/*-
+ * Copyright 2005 Colin Percival
+ * Copyright 2013 Christian Mehlis & René Kijewski
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ * $FreeBSD: src/lib/libmd/sha256.h,v 1.1.2.1 2005/06/24 13:32:25 cperciva Exp $
+ */
+
+#ifndef _SHA256_H_
+#define _SHA256_H_
+
+#include <inttypes.h>
+
+#define SHA256_DIGEST_LENGTH 32
+
+typedef struct SHA256Context {
+    uint32_t state[8];
+    uint32_t count[2];
+    unsigned char buf[64];
+} SHA256_CTX;
+
+void SHA256_Init(SHA256_CTX *);
+void SHA256_Update(SHA256_CTX *, const void *, size_t);
+void SHA256_Final(unsigned char[32], SHA256_CTX *);
+
+#endif /* !_SHA256_H_ */
-- 
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