pidgin: a40ad411: An implementation of SHA-256. Created b...

markdoliner at pidgin.im markdoliner at pidgin.im
Tue Jun 23 14:05:26 EDT 2009


-----------------------------------------------------------------
Revision: a40ad4118790ff992c17b471494164a0dcd7192b
Ancestor: 0ed69cf2b265741af3347af48a5860815ab8f8f9
Author: markdoliner at pidgin.im
Date: 2009-06-23T18:03:48
Branch: im.pidgin.pidgin
URL: http://d.pidgin.im/viewmtn/revision/info/a40ad4118790ff992c17b471494164a0dcd7192b

Modified files:
        libpurple/cipher.c

ChangeLog: 

An implementation of SHA-256.  Created by copying libpurple's SHA-1
implementation then modifying it based on the information in
FIPS PUB 180-2.  Seems to work ok.

The new AIM/ICQ login will use this.

-------------- next part --------------
============================================================
--- libpurple/cipher.c	0eaf88f9d46faea88de4e21f75a8c76d584e9444
+++ libpurple/cipher.c	131b3b2ea9baac3f2672b734a1fe4e835cc5dc5f
@@ -1862,6 +1862,261 @@ static PurpleCipherOps SHA1Ops = {
 };
 
 /*******************************************************************************
+ * SHA-256
+ ******************************************************************************/
+#define SHA256_HMAC_BLOCK_SIZE	64
+#define SHA256_ROTR(X,n) ((((X) >> (n)) | ((X) << (32-(n)))) & 0xFFFFFFFF)
+
+static const guint32 sha256_K[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
+};
+
+struct SHA256Context {
+	guint32 H[8];
+	guint32 W[64];
+
+	gint lenW;
+
+	guint32 sizeHi;
+	guint32 sizeLo;
+};
+
+static void
+sha256_hash_block(struct SHA256Context *sha256_ctx) {
+	gint i;
+	guint32 A, B, C, D, E, F, G, H, T1, T2;
+
+	for(i = 16; i < 64; i++) {
+		sha256_ctx->W[i] =
+			  (SHA256_ROTR(sha256_ctx->W[i-2], 17) ^ SHA256_ROTR(sha256_ctx->W[i-2],  19) ^ (sha256_ctx->W[i-2] >> 10))
+			+ sha256_ctx->W[i-7]
+			+ (SHA256_ROTR(sha256_ctx->W[i-15], 7) ^ SHA256_ROTR(sha256_ctx->W[i-15], 18) ^ (sha256_ctx->W[i-15] >> 3))
+			+ sha256_ctx->W[i-16];
+	}
+
+	A = sha256_ctx->H[0];
+	B = sha256_ctx->H[1];
+	C = sha256_ctx->H[2];
+	D = sha256_ctx->H[3];
+	E = sha256_ctx->H[4];
+	F = sha256_ctx->H[5];
+	G = sha256_ctx->H[6];
+	H = sha256_ctx->H[7];
+
+	for(i = 0; i < 64; i++) {
+        T1 = H
+			+ (SHA256_ROTR(E, 6) ^ SHA256_ROTR(E, 11) ^ SHA256_ROTR(E, 25))
+			+ ((E & F) ^ ((~E) & G))
+			+ sha256_K[i] + sha256_ctx->W[i];
+        T2 = (SHA256_ROTR(A, 2) ^ SHA256_ROTR(A, 13) ^ SHA256_ROTR(A, 22))
+			+ ((A & B) ^ (A & C) ^ (B & C));
+		H = G;
+		G = F;
+		F = E;
+		E = D + T1;
+		D = C;
+		C = B;
+		B = A;
+		A = T1 + T2;
+	}
+
+	sha256_ctx->H[0] += A;
+	sha256_ctx->H[1] += B;
+	sha256_ctx->H[2] += C;
+	sha256_ctx->H[3] += D;
+	sha256_ctx->H[4] += E;
+	sha256_ctx->H[5] += F;
+	sha256_ctx->H[6] += G;
+	sha256_ctx->H[7] += H;
+}
+
+static void
+sha256_set_opt(PurpleCipherContext *context, const gchar *name, void *value) {
+	struct SHA256Context *ctx;
+
+	ctx = purple_cipher_context_get_data(context);
+
+	if(!strcmp(name, "sizeHi")) {
+		ctx->sizeHi = GPOINTER_TO_INT(value);
+	} else if(!strcmp(name, "sizeLo")) {
+		ctx->sizeLo = GPOINTER_TO_INT(value);
+	} else if(!strcmp(name, "lenW")) {
+		ctx->lenW = GPOINTER_TO_INT(value);
+	}
+}
+
+static void *
+sha256_get_opt(PurpleCipherContext *context, const gchar *name) {
+	struct SHA256Context *ctx;
+
+	ctx = purple_cipher_context_get_data(context);
+
+	if(!strcmp(name, "sizeHi")) {
+		return GINT_TO_POINTER(ctx->sizeHi);
+	} else if(!strcmp(name, "sizeLo")) {
+		return GINT_TO_POINTER(ctx->sizeLo);
+	} else if(!strcmp(name, "lenW")) {
+		return GINT_TO_POINTER(ctx->lenW);
+	}
+
+	return NULL;
+}
+
+static void
+sha256_init(PurpleCipherContext *context, void *extra) {
+	struct SHA256Context *sha256_ctx;
+
+	sha256_ctx = g_new0(struct SHA256Context, 1);
+
+	purple_cipher_context_set_data(context, sha256_ctx);
+
+	purple_cipher_context_reset(context, extra);
+}
+
+static void
+sha256_reset(PurpleCipherContext *context, void *extra) {
+	struct SHA256Context *sha256_ctx;
+	gint i;
+
+	sha256_ctx = purple_cipher_context_get_data(context);
+
+	g_return_if_fail(sha256_ctx);
+
+	sha256_ctx->lenW = 0;
+	sha256_ctx->sizeHi = 0;
+	sha256_ctx->sizeLo = 0;
+
+	sha256_ctx->H[0] = 0x6a09e667;
+	sha256_ctx->H[1] = 0xbb67ae85;
+	sha256_ctx->H[2] = 0x3c6ef372;
+	sha256_ctx->H[3] = 0xa54ff53a;
+	sha256_ctx->H[4] = 0x510e527f;
+	sha256_ctx->H[5] = 0x9b05688c;
+	sha256_ctx->H[6] = 0x1f83d9ab;
+	sha256_ctx->H[7] = 0x5be0cd19;
+
+	for(i = 0; i < 64; i++)
+		sha256_ctx->W[i] = 0;
+}
+
+static void
+sha256_uninit(PurpleCipherContext *context) {
+	struct SHA256Context *sha256_ctx;
+
+	purple_cipher_context_reset(context, NULL);
+
+	sha256_ctx = purple_cipher_context_get_data(context);
+
+	memset(sha256_ctx, 0, sizeof(struct SHA256Context));
+
+	g_free(sha256_ctx);
+	sha256_ctx = NULL;
+}
+
+
+static void
+sha256_append(PurpleCipherContext *context, const guchar *data, size_t len) {
+	struct SHA256Context *sha256_ctx;
+	gint i;
+
+	sha256_ctx = purple_cipher_context_get_data(context);
+
+	g_return_if_fail(sha256_ctx);
+
+	for(i = 0; i < len; i++) {
+		sha256_ctx->W[sha256_ctx->lenW / 4] <<= 8;
+		sha256_ctx->W[sha256_ctx->lenW / 4] |= data[i];
+
+		if((++sha256_ctx->lenW) % 64 == 0) {
+			sha256_hash_block(sha256_ctx);
+			sha256_ctx->lenW = 0;
+		}
+
+		sha256_ctx->sizeLo += 8;
+		sha256_ctx->sizeHi += (sha256_ctx->sizeLo < 8);
+	}
+}
+
+static gboolean
+sha256_digest(PurpleCipherContext *context, size_t in_len, guchar digest[32],
+			size_t *out_len)
+{
+	struct SHA256Context *sha256_ctx;
+	guchar pad0x80 = 0x80, pad0x00 = 0x00;
+	guchar padlen[8];
+	gint i;
+
+	g_return_val_if_fail(in_len >= 32, FALSE);
+
+	sha256_ctx = purple_cipher_context_get_data(context);
+
+	g_return_val_if_fail(sha256_ctx, FALSE);
+
+	padlen[0] = (guchar)((sha256_ctx->sizeHi >> 24) & 255);
+	padlen[1] = (guchar)((sha256_ctx->sizeHi >> 16) & 255);
+	padlen[2] = (guchar)((sha256_ctx->sizeHi >> 8) & 255);
+	padlen[3] = (guchar)((sha256_ctx->sizeHi >> 0) & 255);
+	padlen[4] = (guchar)((sha256_ctx->sizeLo >> 24) & 255);
+	padlen[5] = (guchar)((sha256_ctx->sizeLo >> 16) & 255);
+	padlen[6] = (guchar)((sha256_ctx->sizeLo >> 8) & 255);
+	padlen[7] = (guchar)((sha256_ctx->sizeLo >> 0) & 255);
+
+	/* pad with a 1, then zeroes, then length */
+	purple_cipher_context_append(context, &pad0x80, 1);
+	while(sha256_ctx->lenW != 56)
+		purple_cipher_context_append(context, &pad0x00, 1);
+	purple_cipher_context_append(context, padlen, 8);
+
+	for(i = 0; i < 32; i++) {
+		digest[i] = (guchar)(sha256_ctx->H[i / 4] >> 24);
+		sha256_ctx->H[i / 4] <<= 8;
+	}
+
+	purple_cipher_context_reset(context, NULL);
+
+	if(out_len)
+		*out_len = 32;
+
+	return TRUE;
+}
+
+static size_t
+sha256_get_block_size(PurpleCipherContext *context)
+{
+	/* This does not change (in this case) */
+	return SHA256_HMAC_BLOCK_SIZE;
+}
+
+static PurpleCipherOps SHA256Ops = {
+	sha256_set_opt,	/* Set Option		*/
+	sha256_get_opt,	/* Get Option		*/
+	sha256_init,	/* init				*/
+	sha256_reset,	/* reset			*/
+	sha256_uninit,	/* uninit			*/
+	NULL,			/* set iv			*/
+	sha256_append,	/* append			*/
+	sha256_digest,	/* digest			*/
+	NULL,			/* encrypt			*/
+	NULL,			/* decrypt			*/
+	NULL,			/* set salt			*/
+	NULL,			/* get salt size	*/
+	NULL,			/* set key			*/
+	NULL,			/* get key size		*/
+	NULL,			/* set batch mode */
+	NULL,			/* get batch mode */
+	sha256_get_block_size,	/* get block size */
+	NULL			/* set key with len */
+};
+
+/*******************************************************************************
  * RC4
  ******************************************************************************/
 
@@ -2228,6 +2483,7 @@ purple_ciphers_init() {
 
 	purple_ciphers_register_cipher("md5", &MD5Ops);
 	purple_ciphers_register_cipher("sha1", &SHA1Ops);
+	purple_ciphers_register_cipher("sha256", &SHA256Ops);
 	purple_ciphers_register_cipher("md4", &MD4Ops);
 	purple_ciphers_register_cipher("hmac", &HMACOps);
 	purple_ciphers_register_cipher("des", &DESOps);


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