.\" -*- mode: troff; coding: utf-8 -*- .\" Automatically generated by Pod::Man v6.0.2 (Pod::Simple 3.45) .\" .\" Standard preamble: .\" ======================================================================== .de Sp \" Vertical space (when we can't use .PP) .if t .sp .5v .if n .sp .. .de Vb \" Begin verbatim text .ft CW .nf .ne \\$1 .. .de Ve \" End verbatim text .ft R .fi .. .\" \*(C` and \*(C' are quotes in nroff, nothing in troff, for use with C<>. .ie n \{\ . ds C` "" . ds C' "" 'br\} .el\{\ . ds C` . ds C' 'br\} .\" .\" Escape single quotes in literal strings from groff's Unicode transform. .ie \n(.g .ds Aq \(aq .el .ds Aq ' .\" .\" If the F register is >0, we'll generate index entries on stderr for .\" titles (.TH), headers (.SH), subsections (.SS), items (.Ip), and index .\" entries marked with X<> in POD. Of course, you'll have to process the .\" output yourself in some meaningful fashion. .\" .\" Avoid warning from groff about undefined register 'F'. .de IX .. .nr rF 0 .if \n(.g .if rF .nr rF 1 .if (\n(rF:(\n(.g==0)) \{\ . if \nF \{\ . de IX . tm Index:\\$1\t\\n%\t"\\$2" .. . if !\nF==2 \{\ . nr % 0 . nr F 2 . \} . \} .\} .rr rF .\" .\" Required to disable full justification in groff 1.23.0. .if n .ds AD l .\" ======================================================================== .\" .IX Title "EVP_PKEY-X25519 7ssl" .TH EVP_PKEY-X25519 7ssl 2025-10-01 3.6.0 OpenSSL .\" For nroff, turn off justification. Always turn off hyphenation; it makes .\" way too many mistakes in technical documents. .if n .ad l .nh .SH 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 .SH DESCRIPTION .IX Header "DESCRIPTION" The \fBX25519\fR, \fBX448\fR, \fBED25519\fR and \fBED448\fR keytypes are implemented in OpenSSL\*(Aqs default and FIPS providers. These implementations support the associated key, containing the public key \fIpub\fR and the private key \fIpriv\fR. .SS "Common Keygen Parameters for X25519, X448, ED25519 and ED448" .IX Subsection "Common Keygen Parameters for X25519, X448, ED25519 and ED448" The following parameters can be used during key generation by calling \&\fBEVP_PKEY_CTX_set_params()\fR after calling \fBEVP_PKEY_keygen_init()\fR. .IP """properties"" (\fBOSSL_PKEY_PARAM_PROPERTIES\fR) " 4 .IX Item """properties"" (OSSL_PKEY_PARAM_PROPERTIES) " The property query to use when fetching algorithms during the key generation operation. .SS "Keygen Parameters for X25519 and X448" .IX Subsection "Keygen Parameters for X25519 and X448" .IP """dhkem\-ikm"" (\fBOSSL_PKEY_PARAM_DHKEM_IKM\fR) " 4 .IX Item """dhkem-ikm"" (OSSL_PKEY_PARAM_DHKEM_IKM) " DHKEM requires the generation of a keypair using an input key material (seed). Use this to specify the key material used for generation of the private key. This value should not be reused for other purposes. It should have a length of at least 32 for X25519, and 56 for X448. .IP """group"" (\fBOSSL_PKEY_PARAM_GROUP_NAME\fR) " 4 .IX Item """group"" (OSSL_PKEY_PARAM_GROUP_NAME) " 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. .SS "Common Parameters for X25519, X448, ED25519 and ED448" .IX Subsection "Common Parameters for X25519, X448, ED25519 and ED448" In addition to the common parameters that all keytypes should support (see "Common parameters" in \fBprovider\-keymgmt\fR\|(7)), the implementation of these keytypes support the following. .IP """pub"" (\fBOSSL_PKEY_PARAM_PUB_KEY\fR) " 4 .IX Item """pub"" (OSSL_PKEY_PARAM_PUB_KEY) " The public key value. .IP """priv"" (\fBOSSL_PKEY_PARAM_PRIV_KEY\fR) " 4 .IX Item """priv"" (OSSL_PKEY_PARAM_PRIV_KEY) " The private key value. .SS "Parameters for X25519 and X448" .IX Subsection "Parameters for X25519 and X448" .IP """encoded\-pub\-key"" (\fBOSSL_PKEY_PARAM_ENCODED_PUBLIC_KEY\fR) " 4 .IX Item """encoded-pub-key"" (OSSL_PKEY_PARAM_ENCODED_PUBLIC_KEY) " Used for getting and setting the encoding of a public key for the \fBX25519\fR and \&\fBX448\fR key types. Public keys are expected be encoded in a format as defined by RFC7748. .IP """fips\-indicator"" (\fBOSSL_PKEY_PARAM_FIPS_APPROVED_INDICATOR\fR) " 4 .IX Item """fips-indicator"" (OSSL_PKEY_PARAM_FIPS_APPROVED_INDICATOR) " This getter is only supported by X25519 and X448 OpenSSL FIPS provider. Since X25519 and X448 are unapproved in FIPS 140\-3 this getter returns 0. .SS "Parameters for ED25519 and ED448" .IX Subsection "Parameters for ED25519 and ED448" .IP """mandatory\-digest"" (\fBOSSL_PKEY_PARAM_MANDATORY_DIGEST\fR) " 4 .IX Item """mandatory-digest"" (OSSL_PKEY_PARAM_MANDATORY_DIGEST) " The empty string, signifying that no digest may be specified. .SH "CONFORMING TO" .IX Header "CONFORMING TO" .IP "RFC 8032" 4 .IX Item "RFC 8032" .PD 0 .IP "RFC 8410" 4 .IX Item "RFC 8410" .PD .SH EXAMPLES .IX Header "EXAMPLES" An \fBEVP_PKEY\fR context can be obtained by calling: .PP .Vb 2 \& 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); .Ve .PP An \fBX25519\fR key can be generated like this: .PP .Vb 1 \& pkey = EVP_PKEY_Q_keygen(NULL, NULL, "X25519"); .Ve .PP An \fBX448\fR, \fBED25519\fR, or \fBED448\fR key can be generated likewise. .SH "SEE ALSO" .IX Header "SEE ALSO" \&\fBEVP_KEYMGMT\fR\|(3), \fBEVP_PKEY\fR\|(3), \fBprovider\-keymgmt\fR\|(7), \&\fBEVP_KEYEXCH\-X25519\fR\|(7), \fBEVP_KEYEXCH\-X448\fR\|(7), \&\fBEVP_SIGNATURE\-ED25519\fR\|(7), \fBEVP_SIGNATURE\-ED448\fR\|(7) .SH COPYRIGHT .IX Header "COPYRIGHT" Copyright 2020\-2025 The OpenSSL Project Authors. All Rights Reserved. .PP 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 .