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.\" ========================================================================
.\"
.IX Title "ED25519 7"
.TH ED25519 7 "2023-09-11" "1.1.1w" "OpenSSL"
.\" For nroff, turn off justification.  Always turn off hyphenation; it makes
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.nh
.SH "NAME"
Ed25519, Ed448 \&\- EVP_PKEY Ed25519 and Ed448 support
.SH "DESCRIPTION"
.IX Header "DESCRIPTION"
The \fBEd25519\fR and \fBEd448\fR \s-1EVP_PKEY\s0 implementation supports key generation,
one-shot digest sign and digest verify using PureEdDSA and \fBEd25519\fR or \fBEd448\fR
(see \s-1RFC8032\s0). It has associated private and public key formats compatible with
\&\s-1RFC 8410.\s0
.PP
No additional parameters can be set during key generation, one-shot signing or
verification. In particular, because PureEdDSA is used, a digest must \fB\s-1NOT\s0\fR be
specified when signing or verifying.
.SH "NOTES"
.IX Header "NOTES"
The PureEdDSA algorithm does not support the streaming mechanism
of other signature algorithms using, for example, \fBEVP_DigestUpdate()\fR.
The message to sign or verify must be passed using the one-shot
\&\fBEVP_DigestSign()\fR and \fBEVP_DigestVerify()\fR functions.
.PP
When calling \fBEVP_DigestSignInit()\fR or \fBEVP_DigestVerifyInit()\fR, the
digest \fBtype\fR parameter \fB\s-1MUST\s0\fR be set to \fB\s-1NULL\s0\fR.
.PP
Applications wishing to sign certificates (or other structures such as
CRLs or certificate requests) using Ed25519 or Ed448 can either use \fBX509_sign()\fR
or \fBX509_sign_ctx()\fR in the usual way.
.PP
A context for the \fBEd25519\fR algorithm can be obtained by calling:
.PP
.Vb 1
\& EVP_PKEY_CTX *pctx = EVP_PKEY_CTX_new_id(EVP_PKEY_ED25519, NULL);
.Ve
.PP
For the \fBEd448\fR algorithm a context can be obtained by calling:
.PP
.Vb 1
\& EVP_PKEY_CTX *pctx = EVP_PKEY_CTX_new_id(EVP_PKEY_ED448, NULL);
.Ve
.PP
Ed25519 or Ed448 private keys can be set directly using
\&\fBEVP_PKEY_new_raw_private_key\fR\|(3) or loaded from a PKCS#8 private key file
using \fBPEM_read_bio_PrivateKey\fR\|(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.
.PP
Ed25519 or Ed448 public keys can be set directly using
\&\fBEVP_PKEY_new_raw_public_key\fR\|(3) or loaded from a SubjectPublicKeyInfo
structure in a \s-1PEM\s0 file using \fBPEM_read_bio_PUBKEY\fR\|(3) (or similar function).
.PP
Ed25519 and Ed448 can be tested within \fBspeed\fR\|(1) application since version 1.1.1.
Valid algorithm names are \fBed25519\fR, \fBed448\fR and \fBeddsa\fR. If \fBeddsa\fR is
specified, then both Ed25519 and Ed448 are benchmarked.
.SH "EXAMPLES"
.IX Header "EXAMPLES"
This example generates an \fB\s-1ED25519\s0\fR private key and writes it to standard
output in \s-1PEM\s0 format:
.PP
.Vb 9
\& #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_init(pctx);
\& EVP_PKEY_keygen(pctx, &pkey);
\& EVP_PKEY_CTX_free(pctx);
\& PEM_write_PrivateKey(stdout, pkey, NULL, NULL, 0, NULL, NULL);
.Ve
.SH "SEE ALSO"
.IX Header "SEE ALSO"
\&\fBEVP_PKEY_CTX_new\fR\|(3),
\&\fBEVP_PKEY_keygen\fR\|(3),
\&\fBEVP_DigestSignInit\fR\|(3),
\&\fBEVP_DigestVerifyInit\fR\|(3),
.SH "COPYRIGHT"
.IX Header "COPYRIGHT"
Copyright 2017\-2020 The OpenSSL Project Authors. All Rights Reserved.
.PP
Licensed under the OpenSSL license (the \*(L"License\*(R").  You may not use
this file except in compliance with the License.  You can obtain a copy
in the file \s-1LICENSE\s0 in the source distribution or at
<https://www.openssl.org/source/license.html>.

MR SKB