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-rw-r--r--openssl/crypto/aes/aes_ctr.c139
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+/* crypto/aes/aes_ctr.c -*- mode:C; c-file-style: "eay" -*- */
+/* ====================================================================
+ * Copyright (c) 1998-2002 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.
+ * ====================================================================
+ *
+ */
+
+#ifndef AES_DEBUG
+# ifndef NDEBUG
+# define NDEBUG
+# endif
+#endif
+#include <assert.h>
+
+#include <openssl/aes.h>
+#include "aes_locl.h"
+
+/* NOTE: the IV/counter CTR mode is big-endian. The rest of the AES code
+ * is endian-neutral. */
+
+/* increment counter (128-bit int) by 1 */
+static void AES_ctr128_inc(unsigned char *counter) {
+ unsigned long c;
+
+ /* Grab bottom dword of counter and increment */
+ c = GETU32(counter + 12);
+ c++; c &= 0xFFFFFFFF;
+ PUTU32(counter + 12, c);
+
+ /* if no overflow, we're done */
+ if (c)
+ return;
+
+ /* Grab 1st dword of counter and increment */
+ c = GETU32(counter + 8);
+ c++; c &= 0xFFFFFFFF;
+ PUTU32(counter + 8, c);
+
+ /* if no overflow, we're done */
+ if (c)
+ return;
+
+ /* Grab 2nd dword of counter and increment */
+ c = GETU32(counter + 4);
+ c++; c &= 0xFFFFFFFF;
+ PUTU32(counter + 4, c);
+
+ /* if no overflow, we're done */
+ if (c)
+ return;
+
+ /* Grab top dword of counter and increment */
+ c = GETU32(counter + 0);
+ c++; c &= 0xFFFFFFFF;
+ PUTU32(counter + 0, c);
+}
+
+/* The input encrypted as though 128bit counter mode is being
+ * used. The extra state information to record how much of the
+ * 128bit block we have used is contained in *num, and the
+ * encrypted counter is kept in ecount_buf. Both *num and
+ * ecount_buf must be initialised with zeros before the first
+ * call to AES_ctr128_encrypt().
+ *
+ * This algorithm assumes that the counter is in the x lower bits
+ * of the IV (ivec), and that the application has full control over
+ * overflow and the rest of the IV. This implementation takes NO
+ * responsability for checking that the counter doesn't overflow
+ * into the rest of the IV when incremented.
+ */
+void AES_ctr128_encrypt(const unsigned char *in, unsigned char *out,
+ const unsigned long length, const AES_KEY *key,
+ unsigned char ivec[AES_BLOCK_SIZE],
+ unsigned char ecount_buf[AES_BLOCK_SIZE],
+ unsigned int *num) {
+
+ unsigned int n;
+ unsigned long l=length;
+
+ assert(in && out && key && counter && num);
+ assert(*num < AES_BLOCK_SIZE);
+
+ n = *num;
+
+ while (l--) {
+ if (n == 0) {
+ AES_encrypt(ivec, ecount_buf, key);
+ AES_ctr128_inc(ivec);
+ }
+ *(out++) = *(in++) ^ ecount_buf[n];
+ n = (n+1) % AES_BLOCK_SIZE;
+ }
+
+ *num=n;
+}