Updated: 2022/Sep/29

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EVP_PKEY-X25519(7)                  OpenSSL                 EVP_PKEY-X25519(7)



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>.



3.0.12                            2023-05-07                EVP_PKEY-X25519(7)