Updated: 2022/Sep/29

Please read Privacy Policy. It's for your privacy.

ED25519(7)                          OpenSSL                         ED25519(7)

       Ed25519, Ed448 - EVP_PKEY Ed25519 and Ed448 support

       The Ed25519 and Ed448 EVP_PKEY implementation supports key generation,
       one-shot digest sign and digest verify using PureEdDSA and Ed25519 or
       Ed448 (see RFC8032). It has associated private and public key formats
       compatible with RFC 8410.

       No additional parameters can be set during key generation, one-shot
       signing or verification. In particular, because PureEdDSA is used, a
       digest must NOT be specified when signing or verifying.

       The PureEdDSA algorithm does not support the streaming mechanism of
       other signature algorithms using, for example, EVP_DigestUpdate().  The
       message to sign or verify must be passed using the one-shot
       EVP_DigestSign() and EVP_DigestVerify() functions.

       When calling EVP_DigestSignInit() or EVP_DigestVerifyInit(), the digest
       type parameter MUST be set to NULL.

       Applications wishing to sign certificates (or other structures such as
       CRLs or certificate requests) using Ed25519 or Ed448 can either use
       X509_sign() or X509_sign_ctx() in the usual way.

       A context for the Ed25519 algorithm can be obtained by calling:

        EVP_PKEY_CTX *pctx = EVP_PKEY_CTX_new_id(EVP_PKEY_ED25519, NULL);

       For the Ed448 algorithm a context can be obtained by calling:

        EVP_PKEY_CTX *pctx = EVP_PKEY_CTX_new_id(EVP_PKEY_ED448, NULL);

       Ed25519 or Ed448 private keys can be set directly using
       EVP_PKEY_new_raw_private_key(3) or loaded from a PKCS#8 private key
       file using PEM_read_bio_PrivateKey(3) (or similar function). Completely
       new keys can also be generated (see the example below). Setting a
       private key also sets the associated public key.

       Ed25519 or Ed448 public keys can be set directly using
       EVP_PKEY_new_raw_public_key(3) or loaded from a SubjectPublicKeyInfo
       structure in a PEM file using PEM_read_bio_PUBKEY(3) (or similar

       Ed25519 and Ed448 can be tested within speed(1) application since
       version 1.1.1.  Valid algorithm names are ed25519, ed448 and eddsa. If
       eddsa is specified, then both Ed25519 and Ed448 are benchmarked.

       This example generates an ED25519 private key and writes it to standard
       output in PEM format:

        #include <openssl/evp.h>
        #include <openssl/pem.h>
        EVP_PKEY *pkey = NULL;
        EVP_PKEY_CTX *pctx = EVP_PKEY_CTX_new_id(EVP_PKEY_ED25519, NULL);
        EVP_PKEY_keygen(pctx, &pkey);
        PEM_write_PrivateKey(stdout, pkey, NULL, NULL, 0, NULL, NULL);

       EVP_PKEY_CTX_new(3), EVP_PKEY_keygen(3), EVP_DigestSignInit(3),

       Copyright 2017-2020 The OpenSSL Project Authors. All Rights Reserved.

       Licensed under the OpenSSL license (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

1.1.1i                            2020-03-22                        ED25519(7)