From 0275479cb56c7f562f3513fef66c83fc44d1d8c9 Mon Sep 17 00:00:00 2001 From: Erwin Nindl Date: Fri, 22 Jun 2007 13:59:20 +0000 Subject: added libsrtp to svn --- srtp/crypto/include/gf2_8.h | 79 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 79 insertions(+) create mode 100644 srtp/crypto/include/gf2_8.h (limited to 'srtp/crypto/include/gf2_8.h') diff --git a/srtp/crypto/include/gf2_8.h b/srtp/crypto/include/gf2_8.h new file mode 100644 index 0000000..098d37c --- /dev/null +++ b/srtp/crypto/include/gf2_8.h @@ -0,0 +1,79 @@ +/* + * gf2_8.h + * + * GF(256) implementation + * + * David A. McGrew + * Cisco Systems, Inc. + */ + +/* + * + * Copyright (c) 2001-2006, Cisco Systems, Inc. + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * + * Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * + * 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. + * + * Neither the name of the Cisco Systems, Inc. nor the names of its + * contributors may be used to endorse or promote products derived + * from this software without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS 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 + * COPYRIGHT HOLDERS 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. + * + */ + + +#ifndef GF2_8_H +#define GF2_8_H + +#include "datatypes.h" /* for uint8_t definition */ + +typedef uint8_t gf2_8; + +#define gf2_8_field_polynomial 0x1B + +/* + * gf2_8_shift(x) returns + */ + +/* + * gf2_8_shift(z) returns the result of the GF(2^8) 'multiply by x' + * operation, using the field representation from AES; that is, the + * next gf2_8 value in the cyclic representation of that field. The + * value z should be an uint8_t. + */ + +#define gf2_8_shift(z) (((z) & 128) ? \ + (((z) << 1) ^ gf2_8_field_polynomial) : ((z) << 1)) + +gf2_8 +gf2_8_compute_inverse(gf2_8 x); + +void +test_gf2_8(void); + +gf2_8 +gf2_8_multiply(gf2_8 x, gf2_8 y); + +#endif /* GF2_8_H */ -- cgit v1.2.3