NAME

       EVP_SIGNATURE-ED25519, EVP_SIGNATURE-ED448, Ed25519, Ed448 - EVP_PKEY Ed25519 and Ed448 support

DESCRIPTION

       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.

   ED25519 and ED448 Signature Parameters
       No additional parameters can be set during one-shot signing or verification.  In particular, because
       PureEdDSA is used, a digest must NOT be specified when signing or verifying.  See EVP_PKEY-X25519(7) for
       information related to X25519 and X448 keys.

       The following signature parameters can be retrieved using EVP_PKEY_CTX_get_params().

       "algorithm-id" (OSSL_SIGNATURE_PARAM_ALGORITHM_ID) <octet string>
           The parameters are described in provider-signature(7).

NOTES

       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.

       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 function).

       Ed25519  and  Ed448  can  be  tested  with  the  openssl-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.

EXAMPLES

       To sign a message using a ED25519 or ED448 key:

           void do_sign(EVP_PKEY *ed_key, unsigned char *msg, size_t msg_len)
           {
               size_t sig_len;
               unsigned char *sig = NULL;
               EVP_MD_CTX *md_ctx = EVP_MD_CTX_new();

               EVP_DigestSignInit(md_ctx, NULL, NULL, NULL, ed_key);
               /* Calculate the requires size for the signature by passing a NULL buffer */
               EVP_DigestSign(md_ctx, NULL, &sig_len, msg, msg_len);
               sig = OPENSSL_zalloc(sig_len);

               EVP_DigestSign(md_ctx, sig, &sig_len, msg, msg_len);
               ...
               OPENSSL_free(sig);
               EVP_MD_CTX_free(md_ctx);
           }

SEE ALSO

       EVP_PKEY-X25519(7) provider-signature(7), EVP_DigestSignInit(3), EVP_DigestVerifyInit(3),

COPYRIGHT

       Copyright 2017-2021 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>.

3.0.13                                             2025-02-05                        EVP_SIGNATURE-ED25519(7SSL)