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<?xml version="1.0" ?> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <title>EVP_PKEY_fromdata</title> <meta http-equiv="content-type" content="text/html; charset=utf-8" /> <link rev="made" href="mailto:root@localhost" /> </head> <body style="background-color: white"> <ul id="index"> <li><a href="#NAME">NAME</a></li> <li><a href="#SYNOPSIS">SYNOPSIS</a></li> <li><a href="#DESCRIPTION">DESCRIPTION</a> <ul> <li><a href="#Selections">Selections</a></li> </ul> </li> <li><a href="#NOTES">NOTES</a></li> <li><a href="#RETURN-VALUES">RETURN VALUES</a></li> <li><a href="#EXAMPLES">EXAMPLES</a> <ul> <li><a href="#Creating-an-RSA-keypair-using-raw-key-data">Creating an RSA keypair using raw key data</a></li> <li><a href="#Creating-an-ECC-keypair-using-raw-key-data">Creating an ECC keypair using raw key data</a></li> <li><a href="#Finding-out-params-for-an-unknown-key-type">Finding out params for an unknown key type</a></li> </ul> </li> <li><a href="#SEE-ALSO">SEE ALSO</a></li> <li><a href="#HISTORY">HISTORY</a></li> <li><a href="#COPYRIGHT">COPYRIGHT</a></li> </ul> <h1 id="NAME">NAME</h1> <p>EVP_PKEY_fromdata_init, EVP_PKEY_fromdata, EVP_PKEY_fromdata_settable - functions to create keys and key parameters from user data</p> <h1 id="SYNOPSIS">SYNOPSIS</h1> <pre><code> #include <openssl/evp.h> int EVP_PKEY_fromdata_init(EVP_PKEY_CTX *ctx); int EVP_PKEY_fromdata(EVP_PKEY_CTX *ctx, EVP_PKEY **ppkey, int selection, OSSL_PARAM params[]); const OSSL_PARAM *EVP_PKEY_fromdata_settable(EVP_PKEY_CTX *ctx, int selection);</code></pre> <h1 id="DESCRIPTION">DESCRIPTION</h1> <p>The functions described here are used to create new keys from user provided key data, such as <i>n</i>, <i>e</i> and <i>d</i> for a minimal RSA keypair.</p> <p>These functions use an <b>EVP_PKEY_CTX</b> context, which should primarily be created with <a href="../man3/EVP_PKEY_CTX_new_from_name.html">EVP_PKEY_CTX_new_from_name(3)</a> or <a href="../man3/EVP_PKEY_CTX_new_id.html">EVP_PKEY_CTX_new_id(3)</a>.</p> <p>The exact key data that the user can pass depends on the key type. These are passed as an <a href="../man3/OSSL_PARAM.html">OSSL_PARAM(3)</a> array.</p> <p>EVP_PKEY_fromdata_init() initializes a public key algorithm context for creating a key or key parameters from user data.</p> <p>EVP_PKEY_fromdata() creates the structure to store a key or key parameters, given data from <i>params</i>, <i>selection</i> and a context that's been initialized with EVP_PKEY_fromdata_init(). The result is written to <i>*ppkey</i>. <i>selection</i> is described in <a href="#Selections">"Selections"</a>. The parameters that can be used for various types of key are as described by the diverse "Common parameters" sections of the <a href="../man7/EVP_PKEY-RSA.html"><b>EVP_PKEY-RSA</b>(7)</a>, <a href="../man7/EVP_PKEY-DSA.html"><b>EVP_PKEY-DSA</b>(7)</a>, <a href="../man7/EVP_PKEY-DH.html"><b>EVP_PKEY-DH</b>(7)</a>, <a href="../man7/EVP_PKEY-EC.html"><b>EVP_PKEY-EC</b>(7)</a>, <a href="../man7/EVP_PKEY-ED448.html"><b>EVP_PKEY-ED448</b>(7)</a>, <a href="../man7/EVP_PKEY-X25519.html"><b>EVP_PKEY-X25519</b>(7)</a>, <a href="../man7/EVP_PKEY-X448.html"><b>EVP_PKEY-X448</b>(7)</a>, and <a href="../man7/EVP_PKEY-ED25519.html"><b>EVP_PKEY-ED25519</b>(7)</a> pages.</p> <p>EVP_PKEY_fromdata_settable() gets a constant <b>OSSL_PARAM</b> array that describes the settable parameters that can be used with EVP_PKEY_fromdata(). <i>selection</i> is described in <a href="#Selections">"Selections"</a>. See <a href="../man3/OSSL_PARAM.html">OSSL_PARAM(3)</a> for the use of <b>OSSL_PARAM</b> as parameter descriptor.</p> <p>Parameters in the <i>params</i> array that are not among the settable parameters for the given <i>selection</i> are ignored.</p> <h2 id="Selections">Selections</h2> <p>The following constants can be used for <i>selection</i>:</p> <dl> <dt id="EVP_PKEY_KEY_PARAMETERS"><b>EVP_PKEY_KEY_PARAMETERS</b></dt> <dd> <p>Only key parameters will be selected.</p> </dd> <dt id="EVP_PKEY_PUBLIC_KEY"><b>EVP_PKEY_PUBLIC_KEY</b></dt> <dd> <p>Only public key components will be selected. This includes optional key parameters.</p> </dd> <dt id="EVP_PKEY_KEYPAIR"><b>EVP_PKEY_KEYPAIR</b></dt> <dd> <p>Any keypair components will be selected. This includes the private key, public key and key parameters.</p> </dd> </dl> <h1 id="NOTES">NOTES</h1> <p>These functions only work with key management methods coming from a provider. This is the mirror function to <a href="../man3/EVP_PKEY_todata.html">EVP_PKEY_todata(3)</a>.</p> <h1 id="RETURN-VALUES">RETURN VALUES</h1> <p>EVP_PKEY_fromdata_init() and EVP_PKEY_fromdata() return 1 for success and 0 or a negative value for failure. In particular a return value of -2 indicates the operation is not supported by the public key algorithm.</p> <h1 id="EXAMPLES">EXAMPLES</h1> <p>These examples are very terse for the sake of staying on topic, which is the EVP_PKEY_fromdata() set of functions. In real applications, BIGNUMs would be handled and converted to byte arrays with BN_bn2nativepad(), but that's off topic here.</p> <h2 id="Creating-an-RSA-keypair-using-raw-key-data">Creating an RSA keypair using raw key data</h2> <pre><code> #include <openssl/evp.h> /* * These are extremely small to make this example simple. A real * and secure application will not use such small numbers. A real * and secure application is expected to use BIGNUMs, and to build * this array dynamically. */ unsigned long rsa_n = 0xbc747fc5; unsigned long rsa_e = 0x10001; unsigned long rsa_d = 0x7b133399; OSSL_PARAM params[] = { OSSL_PARAM_ulong("n", &rsa_n), OSSL_PARAM_ulong("e", &rsa_e), OSSL_PARAM_ulong("d", &rsa_d), OSSL_PARAM_END }; int main() { EVP_PKEY_CTX *ctx = EVP_PKEY_CTX_new_from_name(NULL, "RSA", NULL); EVP_PKEY *pkey = NULL; if (ctx == NULL || EVP_PKEY_fromdata_init(ctx) <= 0 || EVP_PKEY_fromdata(ctx, &pkey, EVP_PKEY_KEYPAIR, params) <= 0) exit(1); /* Do what you want with |pkey| */ }</code></pre> <h2 id="Creating-an-ECC-keypair-using-raw-key-data">Creating an ECC keypair using raw key data</h2> <pre><code> #include <openssl/evp.h> #include <openssl/param_build.h> #include <openssl/ec.h> /* * Fixed data to represent the private and public key. */ const unsigned char priv_data[] = { 0xb9, 0x2f, 0x3c, 0xe6, 0x2f, 0xfb, 0x45, 0x68, 0x39, 0x96, 0xf0, 0x2a, 0xaf, 0x6c, 0xda, 0xf2, 0x89, 0x8a, 0x27, 0xbf, 0x39, 0x9b, 0x7e, 0x54, 0x21, 0xc2, 0xa1, 0xe5, 0x36, 0x12, 0x48, 0x5d }; /* UNCOMPRESSED FORMAT */ const unsigned char pub_data[] = { POINT_CONVERSION_UNCOMPRESSED, 0xcf, 0x20, 0xfb, 0x9a, 0x1d, 0x11, 0x6c, 0x5e, 0x9f, 0xec, 0x38, 0x87, 0x6c, 0x1d, 0x2f, 0x58, 0x47, 0xab, 0xa3, 0x9b, 0x79, 0x23, 0xe6, 0xeb, 0x94, 0x6f, 0x97, 0xdb, 0xa3, 0x7d, 0xbd, 0xe5, 0x26, 0xca, 0x07, 0x17, 0x8d, 0x26, 0x75, 0xff, 0xcb, 0x8e, 0xb6, 0x84, 0xd0, 0x24, 0x02, 0x25, 0x8f, 0xb9, 0x33, 0x6e, 0xcf, 0x12, 0x16, 0x2f, 0x5c, 0xcd, 0x86, 0x71, 0xa8, 0xbf, 0x1a, 0x47 }; int main() { EVP_PKEY_CTX *ctx; EVP_PKEY *pkey = NULL; BIGNUM *priv; OSSL_PARAM_BLD *param_bld; OSSL_PARAM *params = NULL; int exitcode = 0; priv = BN_bin2bn(priv_data, sizeof(priv_data), NULL); param_bld = OSSL_PARAM_BLD_new(); if (priv != NULL && param_bld != NULL && OSSL_PARAM_BLD_push_utf8_string(param_bld, "group", "prime256v1", 0) && OSSL_PARAM_BLD_push_BN(param_bld, "priv", priv) && OSSL_PARAM_BLD_push_octet_string(param_bld, "pub", pub_data, sizeof(pub_data))) params = OSSL_PARAM_BLD_to_param(param_bld); ctx = EVP_PKEY_CTX_new_from_name(NULL, "EC", NULL); if (ctx == NULL || params == NULL || EVP_PKEY_fromdata_init(ctx) <= 0 || EVP_PKEY_fromdata(ctx, &pkey, EVP_PKEY_KEYPAIR, params) <= 0) { exitcode = 1; } else { /* Do what you want with |pkey| */ } EVP_PKEY_free(pkey); EVP_PKEY_CTX_free(ctx); OSSL_PARAM_free(params); OSSL_PARAM_BLD_free(param_bld); BN_free(priv); exit(exitcode); }</code></pre> <h2 id="Finding-out-params-for-an-unknown-key-type">Finding out params for an unknown key type</h2> <pre><code> #include <openssl/evp.h> #include <openssl/core.h> /* Program expects a key type as first argument */ int main(int argc, char *argv[]) { EVP_PKEY_CTX *ctx = EVP_PKEY_CTX_new_from_name(NULL, argv[1], NULL); const OSSL_PARAM *settable_params = NULL; if (ctx == NULL) exit(1); settable_params = EVP_PKEY_fromdata_settable(ctx, EVP_PKEY_KEYPAIR); if (settable_params == NULL) exit(1); for (; settable_params->key != NULL; settable_params++) { const char *datatype = NULL; switch (settable_params->data_type) { case OSSL_PARAM_INTEGER: datatype = "integer"; break; case OSSL_PARAM_UNSIGNED_INTEGER: datatype = "unsigned integer"; break; case OSSL_PARAM_UTF8_STRING: datatype = "printable string (utf-8 encoding expected)"; break; case OSSL_PARAM_UTF8_PTR: datatype = "printable string pointer (utf-8 encoding expected)"; break; case OSSL_PARAM_OCTET_STRING: datatype = "octet string"; break; case OSSL_PARAM_OCTET_PTR: datatype = "octet string pointer"; break; } printf("%s : %s ", settable_params->key, datatype); if (settable_params->data_size == 0) printf("(unlimited size)\n"); else printf("(maximum size %zu)\n", settable_params->data_size); } }</code></pre> <p>The descriptor <a href="../man3/OSSL_PARAM.html">OSSL_PARAM(3)</a> returned by EVP_PKEY_fromdata_settable() may also be used programmatically, for example with <a href="../man3/OSSL_PARAM_allocate_from_text.html">OSSL_PARAM_allocate_from_text(3)</a>.</p> <h1 id="SEE-ALSO">SEE ALSO</h1> <p><a href="../man3/EVP_PKEY_CTX_new.html">EVP_PKEY_CTX_new(3)</a>, <a href="../man7/provider.html">provider(7)</a>, <a href="../man3/EVP_PKEY_gettable_params.html">EVP_PKEY_gettable_params(3)</a>, <a href="../man3/OSSL_PARAM.html">OSSL_PARAM(3)</a>, <a href="../man3/EVP_PKEY_todata.html">EVP_PKEY_todata(3)</a>, <a href="../man7/EVP_PKEY-RSA.html">EVP_PKEY-RSA(7)</a>, <a href="../man7/EVP_PKEY-DSA.html">EVP_PKEY-DSA(7)</a>, <a href="../man7/EVP_PKEY-DH.html">EVP_PKEY-DH(7)</a>, <a href="../man7/EVP_PKEY-EC.html">EVP_PKEY-EC(7)</a>, <a href="../man7/EVP_PKEY-ED448.html">EVP_PKEY-ED448(7)</a>, <a href="../man7/EVP_PKEY-X25519.html">EVP_PKEY-X25519(7)</a>, <a href="../man7/EVP_PKEY-X448.html">EVP_PKEY-X448(7)</a>, <a href="../man7/EVP_PKEY-ED25519.html">EVP_PKEY-ED25519(7)</a></p> <h1 id="HISTORY">HISTORY</h1> <p>These functions were added in OpenSSL 3.0.</p> <h1 id="COPYRIGHT">COPYRIGHT</h1> <p>Copyright 2019-2022 The OpenSSL Project Authors. All Rights Reserved.</p> <p>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 <a href="https://www.openssl.org/source/license.html">https://www.openssl.org/source/license.html</a>.</p> </body> </html>