| lh | 9ed821d | 2023-04-07 01:36:19 -0700 | [diff] [blame] | 1 | =pod |
| 2 | |
| 3 | =head1 NAME |
| 4 | |
| 5 | X25519, |
| 6 | X448 |
| 7 | - EVP_PKEY X25519 and X448 support |
| 8 | |
| 9 | =head1 DESCRIPTION |
| 10 | |
| 11 | The B<X25519> and B<X448> EVP_PKEY implementation supports key generation and |
| 12 | key derivation using B<X25519> and B<X448>. It has associated private and public |
| 13 | key formats compatible with RFC 8410. |
| 14 | |
| 15 | No additional parameters can be set during key generation. |
| 16 | |
| 17 | The peer public key must be set using EVP_PKEY_derive_set_peer() when |
| 18 | performing key derivation. |
| 19 | |
| 20 | =head1 NOTES |
| 21 | |
| 22 | A context for the B<X25519> algorithm can be obtained by calling: |
| 23 | |
| 24 | EVP_PKEY_CTX *pctx = EVP_PKEY_CTX_new_id(EVP_PKEY_X25519, NULL); |
| 25 | |
| 26 | For the B<X448> algorithm a context can be obtained by calling: |
| 27 | |
| 28 | EVP_PKEY_CTX *pctx = EVP_PKEY_CTX_new_id(EVP_PKEY_X448, NULL); |
| 29 | |
| 30 | X25519 or X448 private keys can be set directly using |
| 31 | L<EVP_PKEY_new_raw_private_key(3)> or loaded from a PKCS#8 private key file |
| 32 | using L<PEM_read_bio_PrivateKey(3)> (or similar function). Completely new keys |
| 33 | can also be generated (see the example below). Setting a private key also sets |
| 34 | the associated public key. |
| 35 | |
| 36 | X25519 or X448 public keys can be set directly using |
| 37 | L<EVP_PKEY_new_raw_public_key(3)> or loaded from a SubjectPublicKeyInfo |
| 38 | structure in a PEM file using L<PEM_read_bio_PUBKEY(3)> (or similar function). |
| 39 | |
| 40 | =head1 EXAMPLES |
| 41 | |
| 42 | This example generates an B<X25519> private key and writes it to standard |
| 43 | output in PEM format: |
| 44 | |
| 45 | #include <openssl/evp.h> |
| 46 | #include <openssl/pem.h> |
| 47 | ... |
| 48 | EVP_PKEY *pkey = NULL; |
| 49 | EVP_PKEY_CTX *pctx = EVP_PKEY_CTX_new_id(EVP_PKEY_X25519, NULL); |
| 50 | EVP_PKEY_keygen_init(pctx); |
| 51 | EVP_PKEY_keygen(pctx, &pkey); |
| 52 | EVP_PKEY_CTX_free(pctx); |
| 53 | PEM_write_PrivateKey(stdout, pkey, NULL, NULL, 0, NULL, NULL); |
| 54 | |
| 55 | The key derivation example in L<EVP_PKEY_derive(3)> can be used with |
| 56 | B<X25519> and B<X448>. |
| 57 | |
| 58 | =head1 SEE ALSO |
| 59 | |
| 60 | L<EVP_PKEY_CTX_new(3)>, |
| 61 | L<EVP_PKEY_keygen(3)>, |
| 62 | L<EVP_PKEY_derive(3)>, |
| 63 | L<EVP_PKEY_derive_set_peer(3)> |
| 64 | |
| 65 | =head1 COPYRIGHT |
| 66 | |
| 67 | Copyright 2017-2020 The OpenSSL Project Authors. All Rights Reserved. |
| 68 | |
| 69 | Licensed under the OpenSSL license (the "License"). You may not use |
| 70 | this file except in compliance with the License. You can obtain a copy |
| 71 | in the file LICENSE in the source distribution or at |
| 72 | L<https://www.openssl.org/source/license.html>. |
| 73 | |
| 74 | =cut |