ccm128.c: initial draft.

crypto/modes/ccm128.c

+/* ====================================================================
+ * Copyright (c) 2011 The OpenSSL Project.  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.
+ *
+ * 3. All advertising materials mentioning features or use of this
+ *    software must display the following acknowledgment:
+ *    "This product includes software developed by the OpenSSL Project
+ *    for use in the OpenSSL Toolkit. (http://www.openssl.org/)"
+ *
+ * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
+ *    endorse or promote products derived from this software without
+ *    prior written permission. For written permission, please contact
+ *    openssl-core@openssl.org.
+ *
+ * 5. Products derived from this software may not be called "OpenSSL"
+ *    nor may "OpenSSL" appear in their names without prior written
+ *    permission of the OpenSSL Project.
+ *
+ * 6. Redistributions of any form whatsoever must retain the following
+ *    acknowledgment:
+ *    "This product includes software developed by the OpenSSL Project
+ *    for use in the OpenSSL Toolkit (http://www.openssl.org/)"
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
+ * EXPRESSED 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 OpenSSL PROJECT OR
+ * ITS 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.
+ * ====================================================================
+ */
+
+#include <openssl/crypto.h>
+#include "modes_lcl.h"
+#include <string.h>
+
+#ifndef MODES_DEBUG
+# ifndef NDEBUG
+#  define NDEBUG
+# endif
+#endif
+#include <assert.h>
+
+typedef struct {
+	union { u8 c[16]; size_t s[16/sizeof(size_t)]; } nonce, cmac,
+							 scratch, inp;
+	u64 blocks;
+	block128_f block;
+	void *key;
+} CCM128_CONTEXT;
+
+/* First you setup M and L parameters and pass the key schedule */
+void CRYPTO_ccm128_init(CCM128_CONTEXT *ctx,
+	unsigned int M,unsigned int L,void *key)
+{
+	memset(ctx->nonce.c,0,sizeof(ctx->nonce.c));
+	ctx->nonce.c[0] = ((u8)(L-1)&7) | (u8)(((M-2)/2)&7)<<3;
+	ctx->blocks = 0;
+	ctx->key = key;
+}
+
+/* !!! Following interfaces are to be called *once* per packet !!! */
+
+/* Then you setup per-message nonce and pass the length of the message */
+int CRYPTO_ccm128_setiv(CCM128_CONTEXT *ctx,
+	const unsigned char *nonce,size_t nlen,size_t mlen)
+{
+	unsigned int L = ctx->nonce.c[0]&7;	/* the L parameter */
+
+	if (nlen<(14-L)) return -1;		/* nonce is too short */
+
+	if (sizeof(mlen)==8 && L>=3) {
+		ctx->nonce.c[8]  = (u8)(mlen>>(56%(sizeof(mlen)*8)));
+		ctx->nonce.c[9]  = (u8)(mlen>>(48%(sizeof(mlen)*8)));
+		ctx->nonce.c[10] = (u8)(mlen>>(40%(sizeof(mlen)*8)));
+		ctx->nonce.c[11] = (u8)(mlen>>(32%(sizeof(mlen)*8)));
+	}
+	else
+		*((size_t *)&ctx->nonce.s[8]) = 0;
+
+	ctx->nonce.c[12] = (u8)(mlen>>24);
+	ctx->nonce.c[13] = (u8)(mlen>>16);
+	ctx->nonce.c[14] = (u8)(mlen>>8);
+	ctx->nonce.c[15] = (u8)mlen;
+
+	ctx->nonce.c[0] &= ~0x40;	/* clear Adata flag */
+	memcpy(&ctx->nonce.c[1],nonce,14-L);
+
+	return 0;
+}
+
+/* Then you pass additional authentication data, this is optional */
+void CRYPTO_ccm128_aad(CCM128_CONTEXT *ctx,
+	const unsigned char *aad,size_t alen)
+{	unsigned int i;
+
+	if (alen==0) return;
+
+	ctx->nonce.c[0] |= 0x40;	/* set Adata flag */
+	(*ctx->block)(ctx->nonce.c,ctx->cmac.c,ctx->key),
+	ctx->blocks++;
+
+	if (alen<(0x10000-0x100)) {
+		ctx->cmac.c[0] ^= (u8)(alen>>8);
+		ctx->cmac.c[1] ^= (u8)alen;
+		i=2;
+	}
+	else if (sizeof(alen)==8 && alen>=(size_t)1<<32) {
+		ctx->cmac.c[0] ^= 0xFF;
+		ctx->cmac.c[1] ^= 0xFF;
+		ctx->cmac.c[2] ^= (u8)(alen>>(56%(sizeof(alen)*8)));
+		ctx->cmac.c[3] ^= (u8)(alen>>(48%(sizeof(alen)*8)));
+		ctx->cmac.c[4] ^= (u8)(alen>>(40%(sizeof(alen)*8)));
+		ctx->cmac.c[5] ^= (u8)(alen>>(32%(sizeof(alen)*8)));
+		ctx->cmac.c[6] ^= (u8)(alen>>24);
+		ctx->cmac.c[7] ^= (u8)(alen>>16);
+		ctx->cmac.c[8] ^= (u8)(alen>>8);
+		ctx->cmac.c[9] ^= (u8)alen;
+		i=10;
+	}
+	else {
+		ctx->cmac.c[0] ^= 0xFF;
+		ctx->cmac.c[1] ^= 0xFE;
+		ctx->cmac.c[2] ^= (u8)(alen>>24);
+		ctx->cmac.c[3] ^= (u8)(alen>>16);
+		ctx->cmac.c[4] ^= (u8)(alen>>8);
+		ctx->cmac.c[5] ^= (u8)alen;
+		i=6;
+	}
+
+	do {
+		for(;i<16 && alen;++i,++aad,--alen)
+			ctx->cmac.c[i] ^= *aad;
+		(*ctx->block)(ctx->cmac.c,ctx->cmac.c,ctx->key),
+		ctx->blocks++;
+		i=0;
+	} while (alen);
+}
+
+/* Finally you encrypt or decrypt the message */
+
+static void ctr128_inc(unsigned char *counter) {
+	unsigned int n=16;
+	u8  c;
+
+	do {
+		--n;
+		c = counter[n];
+		++c;
+		counter[n] = c;
+		if (c) return;
+	} while (n);
+}
+
+int CRYPTO_ccm128_encrypt(CCM128_CONTEXT *ctx,
+	const unsigned char *inp, unsigned char *out,
+	size_t len)
+{
+	size_t		n;
+	unsigned int	i;
+	unsigned char	flags = ctx->nonce.c[0];
+
+	if (!(flags&0x40))
+		(*ctx->block)(ctx->nonce.c,ctx->cmac.c,ctx->key),
+		ctx->blocks++;
+
+	flags &= 7;	/* extract the L parameter */
+	for (n=0,i=15-flags;i<15;++i) {
+		n |= ctx->nonce.c[i]; ctx->nonce.c[i]=0;
+		n <<= 8;
+	}
+	n |= ctx->nonce.c[15];	/* reconstructed length */
+	ctx->nonce.c[15]=1;
+
+	if (n!=len) return -1;	/* length mismatch */
+
+	ctx->blocks += ((len+15)>>3)|1;
+	if (ctx->blocks > (U64(1)<<61))	return -2; /* too much data */
+
+	while (len>=16) {
+#if defined(STRICT_ALIGNMENT)
+		memcpy (ctx->inp.c,inp,16);
+		for (i=0; i<16/sizeof(size_t); ++i)
+			ctx->cmac.s[i] ^= ctx->inp.s[i];
+#else
+		for (i=0; i<16/sizeof(size_t); ++i)
+			ctx->cmac.s[i] ^= ((size_t*)inp)[i];
+#endif
+		(*ctx->block)(ctx->cmac.c,ctx->cmac.c,ctx->key);
+		(*ctx->block)(ctx->nonce.c,ctx->scratch.c,ctx->key);
+		ctr128_inc(ctx->nonce.c);
+#if defined(STRICT_ALIGNMENT)
+		for (i=0; i<16/sizeof(size_t); ++i)
+			ctx->inp.s[i] ^= ctx->scratch.s[i];
+		memcpy(out,ctx->inp.c,16);
+#else
+		for (i=0; i<16/sizeof(size_t); ++i)
+			((size_t*)out)[i] = ctx->scratch.s[i]^((size_t*)inp)[i];
+#endif
+		inp += 16;
+		out += 16;
+		len -= 16;
+	}
+
+	if (len) {
+		for (i=0; i<len; ++i) ctx->cmac.c[i] ^= inp[i];
+		(*ctx->block)(ctx->cmac.c,ctx->cmac.c,ctx->key);
+		(*ctx->block)(ctx->nonce.c,ctx->scratch.c,ctx->key);
+		for (i=0; i<len; ++i) out[i] = ctx->scratch.c[i]^inp[i];
+	}
+
+	for (i=15-flags;i<16;++i)
+		ctx->nonce.c[i]=0;
+
+	(*ctx->block)(ctx->nonce.c,ctx->scratch.c,ctx->key);
+	for (i=0; i<16/sizeof(size_t); ++i)
+		ctx->cmac.s[i] ^= ctx->scratch.s[i];
+
+	return 0;
+}
+
+int CRYPTO_ccm128_decrypt(CCM128_CONTEXT *ctx,
+	const unsigned char *inp, unsigned char *out,
+	size_t len)
+{
+	size_t		n;
+	unsigned int	i;
+	unsigned char	flags = ctx->nonce.c[0];
+
+	if (!(flags&0x40))
+		(*ctx->block)(ctx->nonce.c,ctx->cmac.c,ctx->key);
+
+	flags &= 7;	/* extract the L parameter */
+	for (n=0,i=15-flags;i<15;++i) {
+		n |= ctx->nonce.c[i]; ctx->nonce.c[i]=0;
+		n <<= 8;
+	}
+	n |= ctx->nonce.c[15];	/* reconstructed length */
+	ctx->nonce.c[15]=1;
+
+	if (n!=len) return -1;
+
+	while (len>=16) {
+		(*ctx->block)(ctx->nonce.c,ctx->scratch.c,ctx->key);
+		ctr128_inc(ctx->nonce.c);
+#if defined(STRICT_ALIGNMENT)
+		memcpy (ctx->inp.c,inp,16);
+		for (i=0; i<16/sizeof(size_t); ++i)
+			ctx->cmac.s[i] ^= (ctx->scratch.s[i] ^= ctx->inp.s[i]);
+		memcpy (out,ctx->scratch,16);
+#else
+		for (i=0; i<16/sizeof(size_t); ++i)
+			ctx->cmac.s[i] ^= ((size_t*)out)[i] = ctx->scratch.s[i]^((size_t*)inp)[i];
+#endif
+		(*ctx->block)(ctx->cmac.c,ctx->cmac.c,ctx->key);
+
+		inp += 16;
+		out += 16;
+		len -= 16;
+	}
+
+	if (len) {
+		(*ctx->block)(ctx->nonce.c,ctx->scratch.c,ctx->key);
+		for (i=0; i<len; ++len)
+			ctx->cmac.c[i] ^= (out[i] = ctx->scratch.c[i]^inp[i]);
+		(*ctx->block)(ctx->cmac.c,ctx->cmac.c,ctx->key);
+	}
+
+	for (i=15-flags;i<16;++i)
+		ctx->nonce.c[i]=0;
+
+	(*ctx->block)(ctx->nonce.c,ctx->scratch.c,ctx->key);
+	for (i=0; i<16/sizeof(size_t); ++i)
+		ctx->cmac.s[i] ^= ctx->scratch.s[i];
+
+	return 0;
+}
+
+size_t CRYPTO_ccm128_tag(CCM128_CONTEXT *ctx,unsigned char *tag,size_t len)
+{	unsigned int M = (ctx->nonce.c[0]>>3)&7;	/* the M parameter */
+
+	M *= 2; M += 2;
+	if (len<M)	return 0;
+	memcpy(tag,ctx->cmac.c,M);
+	return M;
+}