Fixes #19782
Clarify that EVP_Q_MAC() can be used as an alternative that allows
setting of the libctx.
Reviewed-by: Paul Dale <pauli@openssl.org>
Reviewed-by: Matt Caswell <matt@openssl.org>
Reviewed-by: Tomas Mraz <tomas@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/19855)
HMAC does not support variable output length digests such as EVP_shake128() and
EVP_shake256().
+HMAC() uses the default B<OSSL_LIB_CTX>.
+Use L<EVP_Q_mac(3)> instead if a library context is required.
+
All of the functions described below are deprecated.
Applications should instead use L<EVP_MAC_CTX_new(3)>, L<EVP_MAC_CTX_free(3)>,
L<EVP_MAC_init(3)>, L<EVP_MAC_update(3)> and L<EVP_MAC_final(3)>
L<EVP_MAC-KMAC(7)>, L<EVP_MAC-BLAKE2(7)>, L<EVP_MAC-Poly1305(7)> and
L<EVP_MAC-Siphash(7)> for additional information.
-Note that the one-shot method HMAC() is still available for compatibility purposes.
+Note that the one-shot method HMAC() is still available for compatibility purposes,
+but this can also be replaced by using EVP_Q_MAC if a library context is required.
=head4 Deprecated low-level validation functions