NAME

       kcapi_kdf_ctr - Counter Mode Key Derivation Function

SYNOPSIS

       int32_t kcapi_kdf_ctr(struct kcapi_handle * handle, const uint8_t * src, uint32_t slen, uint8_t * dst,
                             uint32_t dlen);

ARGUMENTS

       handle
           [in] cipher handle allocated by caller. This cipher handle must be allocated with kcapi_md_init. If
           the caller is interested in a KDF using a keyed message digest, the caller should also call
           kcapi_md_setkey before invoking this function.

       src
           [in] Input data that should be transformed into a key (see below).

       slen
           [in] Length of the src input data.

       dst
           [out] Buffer to store the generated key in,

       dlen
           [in] Length of the dst buffer. This value defines the number of bytes generated by the KDF.

DESCRIPTION

       This function is an implementation of the KDF in counter mode according to SP800-108 section 5.1 as well
       as SP800-56A section 5.8.1 (Single-step KDF).

       SP800-108: The caller must provide Label || 0x00 || Context in src. This src pointer may also be NULL if
       the caller wishes not to provide anything.

       SP800-56A: If a keyed MAC is used, the key shall NOT be the shared secret from the DH operation, but an
       independently generated key. The src pointer is defined as Z || other info where Z is the shared secret
       from DH and other info is an arbitrary string (see SP800-56A section 5.8.1.2).

       return 0 upon success; a negative errno-style error code if an error occurred

AUTHOR

       Stephan Mueller <smueller@chronox.de>
           Author.

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