Comment on the lack of documentation for asymmetric ciphers

    if (!ENGINE_set_id(e, "devcrypto")

        || !ENGINE_set_name(e, "/dev/crypto engine")

        || !ENGINE_set_destroy_function(e, devcrypto_unload)

#if 0                            /* Not supported yet */

/*

 * Asymmetric ciphers aren't well supported with /dev/crypto.  Among the BSD

 * implementations, it seems to only exist in FreeBSD, and regarding the

 * parameters in its crypt_kop, the manual crypto(4) has this to say:

 *

 *    The semantics of these arguments are currently undocumented.

 *

 * Reading through the FreeBSD source code doesn't give much more than

 * their CRK_MOD_EXP implementation for ubsec.

 *

 * It doesn't look much better with cryptodev-linux.  They have the crypt_kop

 * structure as well as the command (CRK_*) in cryptodev.h, but no support

 * seems to be implemented at all for the moment.

 *

 * At the time of writing, it seems impossible to write proper support for

 * FreeBSD's asym features without some very deep knowledge and access to

 * specific kernel modules.

 *

 * /Richard Levitte, 2017-05-11

 */

#if 0

# ifndef OPENSSL_NO_RSA

        || !ENGINE_set_RSA(e, devcrypto_rsa)

# endif