NAME

       OSSL_CRMF_pbm_new, OSSL_CRMF_pbmp_new - functions for producing Password-Based MAC (PBM)

SYNOPSIS

        #include <openssl/crmf.h>

        int OSSL_CRMF_pbm_new(OSSL_LIB_CTX *libctx, const char *propq,
                              const OSSL_CRMF_PBMPARAMETER *pbmp,
                              const unsigned char *msg, size_t msglen,
                              const unsigned char *sec, size_t seclen,
                              unsigned char **mac, size_t *maclen);

        OSSL_CRMF_PBMPARAMETER *OSSL_CRMF_pbmp_new(OSSL_LIB_CTX *libctx, size_t saltlen,
                                                   int owfnid, size_t itercnt,
                                                   int macnid);

DESCRIPTION

       OSSL_CRMF_pbm_new() generates a PBM (Password-Based MAC) based on given PBM parameters
       pbmp, message msg, and secret sec, along with the respective lengths msglen and seclen.
       The optional library context libctx and propq parameters may be used to influence the
       selection of the MAC algorithm referenced in the pbmp; see "ALGORITHM FETCHING" in
       crypto(7) for further information.  On success writes the address of the newly allocated
       MAC via the mac reference parameter and writes the length via the maclen reference
       parameter unless it its NULL.

       OSSL_CRMF_pbmp_new() initializes and returns a new PBMParameter structure with a new
       random salt of given length saltlen, OWF (one-way function) NID owfnid, OWF iteration
       count itercnt, and MAC NID macnid.  The library context libctx parameter may be used to
       select the provider for the random number generation (DRBG) and may be NULL for the
       default.

NOTES

       The algorithms for the OWF (one-way function) and for the MAC (message authentication
       code) may be any with a NID defined in <openssl/objects.h>.  As specified by RFC 4210,
       these should include NID_hmac_sha1.

       RFC 4210 recommends that the salt SHOULD be at least 8 bytes (64 bits) long, where 16
       bytes is common.

       The iteration count must be at least 100, as stipulated by RFC 4211, and is limited to at
       most 100000 to avoid DoS through manipulated or otherwise malformed input.

RETURN VALUES

       OSSL_CRMF_pbm_new() returns 1 on success, 0 on error.

       OSSL_CRMF_pbmp_new() returns a new and initialized OSSL_CRMF_PBMPARAMETER structure, or
       NULL on error.

EXAMPLES

        OSSL_CRMF_PBMPARAMETER *pbm = NULL;
        unsigned char *msg = "Hello";
        unsigned char *sec = "SeCrEt";
        unsigned char *mac = NULL;
        size_t maclen;

        if ((pbm = OSSL_CRMF_pbmp_new(16, NID_sha256, 500, NID_hmac_sha1) == NULL))
            goto err;
        if (!OSSL_CRMF_pbm_new(pbm, msg, 5, sec, 6, &mac, &maclen))
            goto err;

SEE ALSO

       RFC 4211 section 4.4

HISTORY

       The OpenSSL CRMF support was added in OpenSSL 3.0.

COPYRIGHT

       Copyright 2007-2021 The OpenSSL Project Authors. All Rights Reserved.

       Licensed under the Apache License 2.0 (the "License").  You may not use this file except
       in compliance with the License.  You can obtain a copy in the file LICENSE in the source
       distribution or at <https://www.openssl.org/source/license.html>.