NAME

       cl_get_lock - Create Cancel-Lock with libcanlock

SYNOPSIS

       #include <libcanlock-3/canlock.h>

       char *cl_get_lock(cl_hash_version hash,
                         const unsigned char *sec, size_t sec_len,
                         const unsigned char *msg, size_t msg_len);

       Supported values for hash (by version 3.0.0 of libcanlock):
       CL_SHA1 CL_SHA224 CL_SHA256 CL_SHA384 CL_SHA512

DESCRIPTION

       The  cl_get_lock()  function  creates  a  <c-lock>  element  according  to  the  algorithm
       recommended by RFC 8315 in Section 4. The hash algorithm selected for <scheme> is used for
       the HMAC operation too.

       The hash algorithm for <scheme> is selected with hash.

       The local secret is specified with sec (sec_len must be set to the length of sec).
       The length of the local secret should be at least the length of the hash that was selected
       for <scheme> (32 octets for SHA256).

       The Message-ID of the target article (the one for which the lock is intended) is specified
       with msg (msg_len must be set to the length of msg).

       The  Message-ID  msg  can be prepended with an optional User-ID. The length of the User-ID
       must be added to msg_len.  The User-ID must not contain angle brackets.

RETURN VALUE

       Upon successful completion a pointer to the result string is returned.  Otherwise, NULL is
       returned.

       On success the caller is responsible to call free() for the pointer returned as result.

AUTHORS

       Dennis Preiser
       (Based in part on the implementation from G. J. Andruk for Version 2)

       The  base64  implementation  is written by Kungliga Tekniska Hogskolan (Royal Institute of
       Technology, Stockholm, Sweden)

       The hash algorithms are implemented with code from RFC 6234

REPORTING BUGS

       Report bugs to <mailto:michael.baeuerle@gmx.net>.

STANDARDS

       libcanlock tries to comply with the following standards:

       RFC 5537, RFC 6234, RFC 8315

SEE ALSO

       free(3), cl_clear_secret(3), cl_get_key(3), cl_split(3), cl_verify(3), cl_verify_multi(3),
       canlock(1)