mirror of
https://github.com/openssl/openssl.git
synced 2024-12-15 06:01:37 +08:00
8020d79b40
Reviewed-by: Richard Levitte <levitte@openssl.org> (Merged from https://github.com/openssl/openssl/pull/14512)
109 lines
2.8 KiB
Plaintext
109 lines
2.8 KiB
Plaintext
=pod
|
|
|
|
=head1 NAME
|
|
|
|
EVP_KDF-X963 - The X9.63-2001 EVP_KDF implementation
|
|
|
|
=head1 DESCRIPTION
|
|
|
|
The EVP_KDF-X963 algorithm implements the key derivation function (X963KDF).
|
|
X963KDF is used by Cryptographic Message Syntax (CMS) for EC KeyAgreement, to
|
|
derive a key using input such as a shared secret key and shared info.
|
|
|
|
=head2 Identity
|
|
|
|
"X963KDF" is the name for this implementation; it
|
|
can be used with the EVP_KDF_fetch() function.
|
|
|
|
=head2 Supported parameters
|
|
|
|
The supported parameters are:
|
|
|
|
=over 4
|
|
|
|
=item "properties" (B<OSSL_KDF_PARAM_PROPERTIES>) <UTF8 string>
|
|
|
|
=item "digest" (B<OSSL_KDF_PARAM_DIGEST>) <UTF8 string>
|
|
|
|
These parameters work as described in L<EVP_KDF(3)/PARAMETERS>.
|
|
|
|
=item "key" (B<OSSL_KDF_PARAM_KEY>) <octet string>
|
|
|
|
The shared secret used for key derivation.
|
|
This parameter sets the secret.
|
|
|
|
=item "info" (B<OSSL_KDF_PARAM_INFO>) <octet string>
|
|
|
|
This parameter specifies an optional value for shared info.
|
|
|
|
=back
|
|
|
|
=head1 NOTES
|
|
|
|
X963KDF is very similar to the SSKDF that uses a digest as the auxiliary function,
|
|
X963KDF appends the counter to the secret, whereas SSKDF prepends the counter.
|
|
|
|
A context for X963KDF can be obtained by calling:
|
|
|
|
EVP_KDF *kdf = EVP_KDF_fetch(NULL, "X963KDF", NULL);
|
|
EVP_KDF_CTX *kctx = EVP_KDF_CTX_new(kdf);
|
|
|
|
The output length of an X963KDF is specified via the I<keylen>
|
|
parameter to the L<EVP_KDF_derive(3)> function.
|
|
|
|
=head1 EXAMPLES
|
|
|
|
This example derives 10 bytes, with the secret key "secret" and sharedinfo
|
|
value "label":
|
|
|
|
EVP_KDF *kdf;
|
|
EVP_KDF_CTX *kctx;
|
|
unsigned char out[10];
|
|
OSSL_PARAM params[4], *p = params;
|
|
|
|
kdf = EVP_KDF_fetch(NULL, "X963KDF", NULL);
|
|
kctx = EVP_KDF_CTX_new(kdf);
|
|
EVP_KDF_free(kdf);
|
|
|
|
*p++ = OSSL_PARAM_construct_utf8_string(OSSL_KDF_PARAM_DIGEST,
|
|
SN_sha256, strlen(SN_sha256));
|
|
*p++ = OSSL_PARAM_construct_octet_string(OSSL_KDF_PARAM_SECRET,
|
|
"secret", (size_t)6);
|
|
*p++ = OSSL_PARAM_construct_octet_string(OSSL_KDF_PARAM_INFO,
|
|
"label", (size_t)5);
|
|
*p = OSSL_PARAM_construct_end();
|
|
if (EVP_KDF_derive(kctx, out, sizeof(out), params) <= 0) {
|
|
error("EVP_KDF_derive");
|
|
}
|
|
|
|
EVP_KDF_CTX_free(kctx);
|
|
|
|
=head1 CONFORMING TO
|
|
|
|
"SEC 1: Elliptic Curve Cryptography"
|
|
|
|
=head1 SEE ALSO
|
|
|
|
L<EVP_KDF(3)>,
|
|
L<EVP_KDF_CTX_new(3)>,
|
|
L<EVP_KDF_CTX_free(3)>,
|
|
L<EVP_KDF_CTX_set_params(3)>,
|
|
L<EVP_KDF_CTX_get_kdf_size(3)>,
|
|
L<EVP_KDF_derive(3)>,
|
|
L<EVP_KDF(3)/PARAMETERS>
|
|
|
|
=head1 HISTORY
|
|
|
|
This functionality was added to OpenSSL 3.0.
|
|
|
|
=head1 COPYRIGHT
|
|
|
|
Copyright 2019-2021 The OpenSSL Project Authors. All Rights Reserved.
|
|
|
|
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
|
|
L<https://www.openssl.org/source/license.html>.
|
|
|
|
=cut
|