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