/*
 * iterated_hash.c -- nsec3 hash calculation.
 *
 * Copyright (c) 2001-2006, NLnet Labs. All rights reserved.
 *
 * See LICENSE for the license.
 *
 * With thanks to Ben Laurie.
 */
#include "config.h"
#ifdef NSEC3
#if defined(HAVE_SHA1_INIT) && !defined(DEPRECATED_SHA1_INIT)
#include <openssl/sha.h>
#else
#include <openssl/evp.h>
#endif
#include <stdio.h>
#include <assert.h>

#include "iterated_hash.h"
#include "util.h"

int
iterated_hash(unsigned char out[SHA_DIGEST_LENGTH],
        const unsigned char *salt, int saltlength,
        const unsigned char *in, int inlength, int iterations)
{
#if defined(NSEC3) && defined(HAVE_SSL)
#if defined(HAVE_SHA1_INIT) && !defined(DEPRECATED_SHA1_INIT)
        SHA_CTX ctx;
#else
        EVP_MD_CTX* ctx;
#endif
        int n;
#if defined(HAVE_SHA1_INIT) && !defined(DEPRECATED_SHA1_INIT)
#else
        ctx = EVP_MD_CTX_create();
        if(!ctx) {
                log_msg(LOG_ERR, "out of memory in iterated_hash");
                return 0;
        }
#endif
        assert(in && inlength > 0 && iterations >= 0);
        for(n=0 ; n <= iterations ; ++n)
        {
#if defined(HAVE_SHA1_INIT) && !defined(DEPRECATED_SHA1_INIT)
                SHA1_Init(&ctx);
                SHA1_Update(&ctx, in, inlength);
                if(saltlength > 0)
                        SHA1_Update(&ctx, salt, saltlength);
                SHA1_Final(out, &ctx);
#else
                if(!EVP_DigestInit(ctx, EVP_sha1()))
                        log_msg(LOG_ERR, "iterated_hash could not EVP_DigestInit");

                if(!EVP_DigestUpdate(ctx, in, inlength))
                        log_msg(LOG_ERR, "iterated_hash could not EVP_DigestUpdate");
                if(saltlength > 0) {
                        if(!EVP_DigestUpdate(ctx, salt, saltlength))
                                log_msg(LOG_ERR, "iterated_hash could not EVP_DigestUpdate salt");
                }
                if(!EVP_DigestFinal_ex(ctx, out, NULL))
                        log_msg(LOG_ERR, "iterated_hash could not EVP_DigestFinal_ex");
#endif
                in=out;
                inlength=SHA_DIGEST_LENGTH;
        }
#if defined(HAVE_SHA1_INIT) && !defined(DEPRECATED_SHA1_INIT)
#else
        EVP_MD_CTX_destroy(ctx);
#endif
        return SHA_DIGEST_LENGTH;
#else
        (void)out; (void)salt; (void)saltlength;
        (void)in; (void)inlength; (void)iterations;
        return 0;
#endif
}

#endif /* NSEC3 */