NAME

       EVP_PKEY-X25519, EVP_PKEY-X448, EVP_PKEY-ED25519, EVP_PKEY-ED448, EVP_KEYMGMT-X25519,
       EVP_KEYMGMT-X448, EVP_KEYMGMT-ED25519, EVP_KEYMGMT-ED448 - EVP_PKEY X25519, X448, ED25519
       and ED448 keytype and algorithm support

DESCRIPTION

       The X25519, X448, ED25519 and ED448 keytypes are implemented in OpenSSL's default and FIPS
       providers.  These implementations support the associated key, containing the public key
       pub and the private key priv.

       No additional parameters can be set during key generation.

   Common X25519, X448, ED25519 and ED448 parameters
       In addition to the common parameters that all keytypes should support (see "Common
       parameters" in provider-keymgmt(7)), the implementation of these keytypes support the
       following.

       "group" (OSSL_PKEY_PARAM_GROUP_NAME) <UTF8 string>
           This is only supported by X25519 and X448. The group name must be "x25519" or "x448"
           respectively for those algorithms. This is only present for consistency with other key
           exchange algorithms and is typically not needed.

       "pub" (OSSL_PKEY_PARAM_PUB_KEY) <octet string>
           The public key value.

       "priv" (OSSL_PKEY_PARAM_PRIV_KEY) <octet string>
           The private key value.

       "encoded-pub-key" (OSSL_PKEY_PARAM_ENCODED_PUBLIC_KEY) <octet string>
           Used for getting and setting the encoding of a public key for the X25519 and X448 key
           types. Public keys are expected be encoded in a format as defined by RFC7748.

   ED25519 and ED448 parameters
       "mandatory-digest" (OSSL_PKEY_PARAM_MANDATORY_DIGEST) <UTF8 string>
           The empty string, signifying that no digest may be specified.

CONFORMING TO

       RFC 8032
       RFC 8410

EXAMPLES

       An EVP_PKEY context can be obtained by calling:

           EVP_PKEY_CTX *pctx =
               EVP_PKEY_CTX_new_from_name(NULL, "X25519", NULL);

           EVP_PKEY_CTX *pctx =
               EVP_PKEY_CTX_new_from_name(NULL, "X448", NULL);

           EVP_PKEY_CTX *pctx =
               EVP_PKEY_CTX_new_from_name(NULL, "ED25519", NULL);

           EVP_PKEY_CTX *pctx =
               EVP_PKEY_CTX_new_from_name(NULL, "ED448", NULL);

       An X25519 key can be generated like this:

           pkey = EVP_PKEY_Q_keygen(NULL, NULL, "X25519");

       An X448, ED25519, or ED448 key can be generated likewise.

SEE ALSO

       EVP_KEYMGMT(3), EVP_PKEY(3), provider-keymgmt(7), EVP_KEYEXCH-X25519(7),
       EVP_KEYEXCH-X448(7), EVP_SIGNATURE-ED25519(7), EVP_SIGNATURE-ED448(7)

COPYRIGHT

       Copyright 2020-2021 The OpenSSL Project Authors. All Rights Reserved.

       Licensed under the Apache License 2.0 (the "License").  You may not use this file except
       in compliance with the License.  You can obtain a copy in the file LICENSE in the source
       distribution or at <https://www.openssl.org/source/license.html>.