1=pod 2 3=head1 NAME 4 5EVP_PKEY_todata, EVP_PKEY_export 6- functions to return keys as an array of key parameters 7 8=head1 SYNOPSIS 9 10 #include <openssl/evp.h> 11 12 int EVP_PKEY_todata(const EVP_PKEY *pkey, int selection, OSSL_PARAM **params); 13 int EVP_PKEY_export(const EVP_PKEY *pkey, int selection, 14 OSSL_CALLBACK *export_cb, void *export_cbarg); 15 16=head1 DESCRIPTION 17 18The functions described here are used to extract B<EVP_PKEY> key values as an 19array of L<OSSL_PARAM(3)>. 20 21EVP_PKEY_todata() extracts values from a key I<pkey> using the I<selection>. 22I<selection> is described in L<EVP_PKEY_fromdata(3)/Selections>. 23L<OSSL_PARAM_free(3)> should be used to free the returned parameters in 24I<*params>. 25 26EVP_PKEY_export() is similar to EVP_PKEY_todata() but uses a callback 27I<export_cb> that gets passed the value of I<export_cbarg>. 28See L<openssl-core.h(7)> for more information about the callback. Note that the 29L<OSSL_PARAM(3)> array that is passed to the callback is not persistent after the 30callback returns. The user must preserve the items of interest, or use 31EVP_PKEY_todata() if persistence is required. 32 33=head1 NOTES 34 35These functions only work with key management methods coming from a provider. 36This is the mirror function to L<EVP_PKEY_fromdata(3)>. 37 38=head1 RETURN VALUES 39 40EVP_PKEY_todata() and EVP_PKEY_export() return 1 for success and 0 for failure. 41 42=head1 SEE ALSO 43 44L<OSSL_PARAM(3)>, 45L<openssl-core.h(7)>, 46L<EVP_PKEY_fromdata(3)>, 47L<EVP_PKEY-RSA(7)>, 48L<EVP_PKEY-EC(7)>, 49L<EVP_PKEY-DSA(7)>, 50L<EVP_PKEY-ED25519(7)> 51L<EVP_PKEY-ED448(7)>, 52L<EVP_PKEY-DH(7)>, 53L<EVP_PKEY-X25519(7)>, 54L<EVP_PKEY-X448(7)>, 55L<EVP_PKEY-ML-DSA(7)>, 56L<EVP_PKEY-ML-KEM(7)>, 57L<EVP_PKEY-SLH-DSA(7)>. 58 59=head1 HISTORY 60 61These functions were added in OpenSSL 3.0. 62 63Support for B<ML-DSA>, B<ML-KEM> and B<SLH-DSA> was added in OpenSSL 3.5. 64 65=head1 COPYRIGHT 66 67Copyright 2021-2025 The OpenSSL Project Authors. All Rights Reserved. 68 69Licensed under the Apache License 2.0 (the "License"). You may not use 70this file except in compliance with the License. You can obtain a copy 71in the file LICENSE in the source distribution or at 72L<https://www.openssl.org/source/license.html>. 73 74=cut 75 76