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Title "EVP_PKEY_TODATA 3"
EVP_PKEY_TODATA 3 "2023-05-30" "3.0.9" "OpenSSL"
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"NAME"
EVP_PKEY_todata, EVP_PKEY_export \- functions to return keys as an array of key parameters
"SYNOPSIS"
Header "SYNOPSIS" .Vb 1 #include <openssl/evp.h> \& int EVP_PKEY_todata(const EVP_PKEY *pkey, int selection, OSSL_PARAM **params); int EVP_PKEY_export(const EVP_PKEY *pkey, int selection, OSSL_CALLBACK *export_cb, void *export_cbarg); .Ve
"DESCRIPTION"
Header "DESCRIPTION" The functions described here are used to extract \s-1EVP_PKEY\s0 key values as an array of \s-1OSSL_PARAM\s0\|(3).

\fBEVP_PKEY_todata() extracts values from a key pkey using the selection. \fIselection is described in \*(L"Selections\*(R" in EVP_PKEY_fromdata\|(3). \fBOSSL_PARAM_free\|(3) should be used to free the returned parameters in \fI*params.

\fBEVP_PKEY_export() is similiar to EVP_PKEY_todata() but uses a callback \fIexport_cb that gets passed the value of export_cbarg. See openssl-core.h\|(7) for more information about the callback. Note that the \s-1OSSL_PARAM\s0\|(3) array that is passed to the callback is not persistent after the callback returns. The user must preserve the items of interest, or use \fBEVP_PKEY_todata() if persistence is required.

"NOTES"
Header "NOTES" These functions only work with key management methods coming from a provider. This is the mirror function to EVP_PKEY_fromdata\|(3).
"RETURN VALUES"
Header "RETURN VALUES" \fBEVP_PKEY_todata() and EVP_PKEY_export() return 1 for success and 0 for failure.
"SEE ALSO"
Header "SEE ALSO" \s-1OSSL_PARAM\s0\|(3), openssl-core.h\|(7), \fBEVP_PKEY_fromdata\|(3), \s-1EVP_PKEY-RSA\s0\|(7), \s-1EVP_PKEY-DSA\s0\|(7), \s-1EVP_PKEY-DH\s0\|(7), \s-1EVP_PKEY-EC\s0\|(7), \s-1EVP_PKEY-ED448\s0\|(7), \s-1EVP_PKEY-X25519\s0\|(7), \s-1EVP_PKEY-X448\s0\|(7), \s-1EVP_PKEY-ED25519\s0\|(7)
"HISTORY"
Header "HISTORY" These functions were added in OpenSSL 3.0.
"COPYRIGHT"
Header "COPYRIGHT" Copyright 2021 The OpenSSL Project Authors. All Rights Reserved.

Licensed under the Apache License 2.0 (the \*(L"License\*(R"). You may not use this file except in compliance with the License. You can obtain a copy in the file \s-1LICENSE\s0 in the source distribution or at <https://www.openssl.org/source/license.html>.