cl_get_lock - Create Cancel-Lock with libcanlock

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

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.

Name

       cl_get_lock - Create Cancel-Lock with libcanlock

Reporting Bugs

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

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.

Standards

libcanlock tries to comply with the following standards:

       RFC 5537, RFC 6234, RFC 8315

Synopsis

#include<libcanlock-3/canlock.h>char*cl_get_lock(cl_hash_versionhash,constunsignedchar*sec,size_tsec_len,constunsignedchar*msg,size_tmsg_len);

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