| Index: libsrtp/crypto/rng/ctr_prng.c
|
| ===================================================================
|
| --- libsrtp/crypto/rng/ctr_prng.c (revision 0)
|
| +++ libsrtp/crypto/rng/ctr_prng.c (revision 0)
|
| @@ -0,0 +1,108 @@
|
| +/*
|
| + * ctr_prng.c
|
| + *
|
| + * counter mode based pseudorandom source
|
| + *
|
| + * 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.
|
| + *
|
| + */
|
| +
|
| +
|
| +#include "prng.h"
|
| +
|
| +/* single, global prng structure */
|
| +
|
| +ctr_prng_t ctr_prng;
|
| +
|
| +err_status_t
|
| +ctr_prng_init(rand_source_func_t random_source) {
|
| + uint8_t tmp_key[32];
|
| + err_status_t status;
|
| +
|
| + /* initialize output count to zero */
|
| + ctr_prng.octet_count = 0;
|
| +
|
| + /* set random source */
|
| + ctr_prng.rand = random_source;
|
| +
|
| + /* initialize secret key from random source */
|
| + status = random_source(tmp_key, 32);
|
| + if (status)
|
| + return status;
|
| +
|
| + /* initialize aes ctr context with random key */
|
| + status = aes_icm_context_init(&ctr_prng.state, tmp_key, 30);
|
| + if (status)
|
| + return status;
|
| +
|
| + return err_status_ok;
|
| +}
|
| +
|
| +err_status_t
|
| +ctr_prng_get_octet_string(void *dest, uint32_t len) {
|
| + err_status_t status;
|
| +
|
| + /*
|
| + * if we need to re-initialize the prng, do so now
|
| + *
|
| + * avoid 32-bit overflows by subtracting instead of adding
|
| + */
|
| + if (ctr_prng.octet_count > MAX_PRNG_OUT_LEN - len) {
|
| + status = ctr_prng_init(ctr_prng.rand);
|
| + if (status)
|
| + return status;
|
| + }
|
| + ctr_prng.octet_count += len;
|
| +
|
| + /*
|
| + * write prng output
|
| + */
|
| + status = aes_icm_output(&ctr_prng.state, (uint8_t*)dest, len);
|
| + if (status)
|
| + return status;
|
| +
|
| + return err_status_ok;
|
| +}
|
| +
|
| +err_status_t
|
| +ctr_prng_deinit(void) {
|
| +
|
| + /* nothing */
|
| +
|
| + return err_status_ok;
|
| +}
|
|
|
| Property changes on: libsrtp/crypto/rng/ctr_prng.c
|
| ___________________________________________________________________
|
| Added: svn:eol-style
|
| + LF
|
|
|
|
|