1*0Sstevel@tonic-gate /* crypto/aes/aes_ctr.c -*- mode:C; c-file-style: "eay" -*- */ 2*0Sstevel@tonic-gate /* ==================================================================== 3*0Sstevel@tonic-gate * Copyright (c) 1998-2002 The OpenSSL Project. All rights reserved. 4*0Sstevel@tonic-gate * 5*0Sstevel@tonic-gate * Redistribution and use in source and binary forms, with or without 6*0Sstevel@tonic-gate * modification, are permitted provided that the following conditions 7*0Sstevel@tonic-gate * are met: 8*0Sstevel@tonic-gate * 9*0Sstevel@tonic-gate * 1. Redistributions of source code must retain the above copyright 10*0Sstevel@tonic-gate * notice, this list of conditions and the following disclaimer. 11*0Sstevel@tonic-gate * 12*0Sstevel@tonic-gate * 2. Redistributions in binary form must reproduce the above copyright 13*0Sstevel@tonic-gate * notice, this list of conditions and the following disclaimer in 14*0Sstevel@tonic-gate * the documentation and/or other materials provided with the 15*0Sstevel@tonic-gate * distribution. 16*0Sstevel@tonic-gate * 17*0Sstevel@tonic-gate * 3. All advertising materials mentioning features or use of this 18*0Sstevel@tonic-gate * software must display the following acknowledgment: 19*0Sstevel@tonic-gate * "This product includes software developed by the OpenSSL Project 20*0Sstevel@tonic-gate * for use in the OpenSSL Toolkit. (http://www.openssl.org/)" 21*0Sstevel@tonic-gate * 22*0Sstevel@tonic-gate * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to 23*0Sstevel@tonic-gate * endorse or promote products derived from this software without 24*0Sstevel@tonic-gate * prior written permission. For written permission, please contact 25*0Sstevel@tonic-gate * openssl-core@openssl.org. 26*0Sstevel@tonic-gate * 27*0Sstevel@tonic-gate * 5. Products derived from this software may not be called "OpenSSL" 28*0Sstevel@tonic-gate * nor may "OpenSSL" appear in their names without prior written 29*0Sstevel@tonic-gate * permission of the OpenSSL Project. 30*0Sstevel@tonic-gate * 31*0Sstevel@tonic-gate * 6. Redistributions of any form whatsoever must retain the following 32*0Sstevel@tonic-gate * acknowledgment: 33*0Sstevel@tonic-gate * "This product includes software developed by the OpenSSL Project 34*0Sstevel@tonic-gate * for use in the OpenSSL Toolkit (http://www.openssl.org/)" 35*0Sstevel@tonic-gate * 36*0Sstevel@tonic-gate * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY 37*0Sstevel@tonic-gate * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 38*0Sstevel@tonic-gate * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 39*0Sstevel@tonic-gate * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR 40*0Sstevel@tonic-gate * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 41*0Sstevel@tonic-gate * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 42*0Sstevel@tonic-gate * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 43*0Sstevel@tonic-gate * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 44*0Sstevel@tonic-gate * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, 45*0Sstevel@tonic-gate * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 46*0Sstevel@tonic-gate * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED 47*0Sstevel@tonic-gate * OF THE POSSIBILITY OF SUCH DAMAGE. 48*0Sstevel@tonic-gate * ==================================================================== 49*0Sstevel@tonic-gate * 50*0Sstevel@tonic-gate */ 51*0Sstevel@tonic-gate 52*0Sstevel@tonic-gate #ifndef AES_DEBUG 53*0Sstevel@tonic-gate # ifndef NDEBUG 54*0Sstevel@tonic-gate # define NDEBUG 55*0Sstevel@tonic-gate # endif 56*0Sstevel@tonic-gate #endif 57*0Sstevel@tonic-gate #include <assert.h> 58*0Sstevel@tonic-gate 59*0Sstevel@tonic-gate #include <openssl/aes.h> 60*0Sstevel@tonic-gate #include "aes_locl.h" 61*0Sstevel@tonic-gate 62*0Sstevel@tonic-gate /* NOTE: CTR mode is big-endian. The rest of the AES code 63*0Sstevel@tonic-gate * is endian-neutral. */ 64*0Sstevel@tonic-gate 65*0Sstevel@tonic-gate /* increment counter (128-bit int) by 1 */ 66*0Sstevel@tonic-gate static void AES_ctr128_inc(unsigned char *counter) { 67*0Sstevel@tonic-gate unsigned long c; 68*0Sstevel@tonic-gate 69*0Sstevel@tonic-gate /* Grab bottom dword of counter and increment */ 70*0Sstevel@tonic-gate #ifdef L_ENDIAN 71*0Sstevel@tonic-gate c = GETU32(counter + 0); 72*0Sstevel@tonic-gate c++; 73*0Sstevel@tonic-gate PUTU32(counter + 0, c); 74*0Sstevel@tonic-gate #else 75*0Sstevel@tonic-gate c = GETU32(counter + 12); 76*0Sstevel@tonic-gate c++; 77*0Sstevel@tonic-gate PUTU32(counter + 12, c); 78*0Sstevel@tonic-gate #endif 79*0Sstevel@tonic-gate 80*0Sstevel@tonic-gate /* if no overflow, we're done */ 81*0Sstevel@tonic-gate if (c) 82*0Sstevel@tonic-gate return; 83*0Sstevel@tonic-gate 84*0Sstevel@tonic-gate /* Grab 1st dword of counter and increment */ 85*0Sstevel@tonic-gate #ifdef L_ENDIAN 86*0Sstevel@tonic-gate c = GETU32(counter + 4); 87*0Sstevel@tonic-gate c++; 88*0Sstevel@tonic-gate PUTU32(counter + 4, c); 89*0Sstevel@tonic-gate #else 90*0Sstevel@tonic-gate c = GETU32(counter + 8); 91*0Sstevel@tonic-gate c++; 92*0Sstevel@tonic-gate PUTU32(counter + 8, c); 93*0Sstevel@tonic-gate #endif 94*0Sstevel@tonic-gate 95*0Sstevel@tonic-gate /* if no overflow, we're done */ 96*0Sstevel@tonic-gate if (c) 97*0Sstevel@tonic-gate return; 98*0Sstevel@tonic-gate 99*0Sstevel@tonic-gate /* Grab 2nd dword of counter and increment */ 100*0Sstevel@tonic-gate #ifdef L_ENDIAN 101*0Sstevel@tonic-gate c = GETU32(counter + 8); 102*0Sstevel@tonic-gate c++; 103*0Sstevel@tonic-gate PUTU32(counter + 8, c); 104*0Sstevel@tonic-gate #else 105*0Sstevel@tonic-gate c = GETU32(counter + 4); 106*0Sstevel@tonic-gate c++; 107*0Sstevel@tonic-gate PUTU32(counter + 4, c); 108*0Sstevel@tonic-gate #endif 109*0Sstevel@tonic-gate 110*0Sstevel@tonic-gate /* if no overflow, we're done */ 111*0Sstevel@tonic-gate if (c) 112*0Sstevel@tonic-gate return; 113*0Sstevel@tonic-gate 114*0Sstevel@tonic-gate /* Grab top dword of counter and increment */ 115*0Sstevel@tonic-gate #ifdef L_ENDIAN 116*0Sstevel@tonic-gate c = GETU32(counter + 12); 117*0Sstevel@tonic-gate c++; 118*0Sstevel@tonic-gate PUTU32(counter + 12, c); 119*0Sstevel@tonic-gate #else 120*0Sstevel@tonic-gate c = GETU32(counter + 0); 121*0Sstevel@tonic-gate c++; 122*0Sstevel@tonic-gate PUTU32(counter + 0, c); 123*0Sstevel@tonic-gate #endif 124*0Sstevel@tonic-gate 125*0Sstevel@tonic-gate } 126*0Sstevel@tonic-gate 127*0Sstevel@tonic-gate /* The input encrypted as though 128bit counter mode is being 128*0Sstevel@tonic-gate * used. The extra state information to record how much of the 129*0Sstevel@tonic-gate * 128bit block we have used is contained in *num, and the 130*0Sstevel@tonic-gate * encrypted counter is kept in ecount_buf. Both *num and 131*0Sstevel@tonic-gate * ecount_buf must be initialised with zeros before the first 132*0Sstevel@tonic-gate * call to AES_ctr128_encrypt(). 133*0Sstevel@tonic-gate * 134*0Sstevel@tonic-gate * This algorithm assumes that the counter is in the x lower bits 135*0Sstevel@tonic-gate * of the IV (ivec), and that the application has full control over 136*0Sstevel@tonic-gate * overflow and the rest of the IV. This implementation takes NO 137*0Sstevel@tonic-gate * responsability for checking that the counter doesn't overflow 138*0Sstevel@tonic-gate * into the rest of the IV when incremented. 139*0Sstevel@tonic-gate */ 140*0Sstevel@tonic-gate void AES_ctr128_encrypt(const unsigned char *in, unsigned char *out, 141*0Sstevel@tonic-gate const unsigned long length, const AES_KEY *key, 142*0Sstevel@tonic-gate unsigned char ivec[AES_BLOCK_SIZE], 143*0Sstevel@tonic-gate unsigned char ecount_buf[AES_BLOCK_SIZE], 144*0Sstevel@tonic-gate unsigned int *num) { 145*0Sstevel@tonic-gate 146*0Sstevel@tonic-gate unsigned int n; 147*0Sstevel@tonic-gate unsigned long l=length; 148*0Sstevel@tonic-gate 149*0Sstevel@tonic-gate assert(in && out && key && counter && num); 150*0Sstevel@tonic-gate assert(*num < AES_BLOCK_SIZE); 151*0Sstevel@tonic-gate 152*0Sstevel@tonic-gate n = *num; 153*0Sstevel@tonic-gate 154*0Sstevel@tonic-gate while (l--) { 155*0Sstevel@tonic-gate if (n == 0) { 156*0Sstevel@tonic-gate AES_encrypt(ivec, ecount_buf, key); 157*0Sstevel@tonic-gate AES_ctr128_inc(ivec); 158*0Sstevel@tonic-gate } 159*0Sstevel@tonic-gate *(out++) = *(in++) ^ ecount_buf[n]; 160*0Sstevel@tonic-gate n = (n+1) % AES_BLOCK_SIZE; 161*0Sstevel@tonic-gate } 162*0Sstevel@tonic-gate 163*0Sstevel@tonic-gate *num=n; 164*0Sstevel@tonic-gate } 165