Automatically generated by Pod::Man 4.14 (Pod::Simple 3.42)

Standard preamble:
========================================================================
..

..

.. Set up some character translations and predefined strings. \*(-- will
give an unbreakable dash, \*(PI will give pi, \*(L" will give a left
double quote, and \*(R" will give a right double quote. \*(C+ will
give a nicer C++. Capital omega is used to do unbreakable dashes and
therefore won't be available. \*(C` and \*(C' expand to `' in nroff,
nothing in troff, for use with C<>.
.tr \(*W- . ds -- \(*W- . ds PI pi . if (\n(.H=4u)&(1m=24u) .ds -- \(*W\h'-12u'\(*W\h'-12u'-\" diablo 10 pitch . if (\n(.H=4u)&(1m=20u) .ds -- \(*W\h'-12u'\(*W\h'-8u'-\" diablo 12 pitch . ds L" "" . ds R" "" . ds C` "" . ds C' "" 'br\} . ds -- \|\(em\| . ds PI \(*p . ds L" `` . ds R" '' . ds C` . ds C' 'br\}
Escape single quotes in literal strings from groff's Unicode transform.

If the F register is >0, we'll generate index entries on stderr for
titles (.TH), headers (.SH), subsections (.SS), items (.Ip), and index
entries marked with X<> in POD. Of course, you'll have to process the
output yourself in some meaningful fashion.

Avoid warning from groff about undefined register 'F'.
.. .nr rF 0 . if \nF \{\ . de IX . tm Index:\\$1\t\\n%\t"\\$2" .. . if !\nF==2 \{\ . nr % 0 . nr F 2 . \} . \} .\} .rr rF
Accent mark definitions (@(#)ms.acc 1.5 88/02/08 SMI; from UCB 4.2).
Fear. Run. Save yourself. No user-serviceable parts.
. \" fudge factors for nroff and troff . ds #H 0 . ds #V .8m . ds #F .3m . ds #[ \f1 . ds #] .\} . ds #H ((1u-(\\\\n(.fu%2u))*.13m) . ds #V .6m . ds #F 0 . ds #[ \& . ds #] \& .\} . \" simple accents for nroff and troff . ds ' \& . ds ` \& . ds ^ \& . ds , \& . ds ~ ~ . ds / .\} . ds ' \\k:\h'-(\\n(.wu*8/10-\*(#H)'\'\h"|\\n:u" . ds ` \\k:\h'-(\\n(.wu*8/10-\*(#H)'\`\h'|\\n:u' . ds ^ \\k:\h'-(\\n(.wu*10/11-\*(#H)'^\h'|\\n:u' . ds , \\k:\h'-(\\n(.wu*8/10)',\h'|\\n:u' . ds ~ \\k:\h'-(\\n(.wu-\*(#H-.1m)'~\h'|\\n:u' . ds / \\k:\h'-(\\n(.wu*8/10-\*(#H)'\z\(sl\h'|\\n:u' .\} . \" troff and (daisy-wheel) nroff accents . \" corrections for vroff . \" for low resolution devices (crt and lpr) \{\ . ds : e . ds 8 ss . ds o a . ds d- d\h'-1'\(ga . ds D- D\h'-1'\(hy . ds th \o'bp' . ds Th \o'LP' . ds ae ae . ds Ae AE .\} ========================================================================

Title "EVP_PKEY_FROMDATA 3ossl" For nroff, turn off justification. Always turn off hyphenation; it makes
way too many mistakes in technical documents.
EVP_PKEY_fromdata_init, EVP_PKEY_fromdata, EVP_PKEY_fromdata_settable \- functions to create keys and key parameters from user data Header "SYNOPSIS" .Vb 1 #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); .Ve Header "DESCRIPTION" The functions described here are used to create new keys from user provided key data, such as n, e and d for a minimal \s-1RSA\s0 keypair.

These functions use an \s-1EVP_PKEY_CTX\s0 context, which should primarily be created with EVP_PKEY_CTX_new_from_name\|(3) or \fBEVP_PKEY_CTX_new_id\|(3).

The exact key data that the user can pass depends on the key type. These are passed as an \s-1OSSL_PARAM\s0\|(3) array.

\fBEVP_PKEY_fromdata_init() initializes a public key algorithm context for creating a key or key parameters from user data.

\fBEVP_PKEY_fromdata() creates the structure to store a key or key parameters, given data from params, selection and a context that's been initialized with EVP_PKEY_fromdata_init(). The result is written to *ppkey. \fIselection is described in \*(L"Selections\*(R". The parameters that can be used for various types of key are as described by the diverse \*(L"Common parameters\*(R" sections of the \fB\s-1EVP_PKEY-RSA\s0(7), \fB\s-1EVP_PKEY-DSA\s0(7), \fB\s-1EVP_PKEY-DH\s0(7), \fB\s-1EVP_PKEY-EC\s0(7), \fB\s-1EVP_PKEY-ED448\s0(7), \fB\s-1EVP_PKEY-X25519\s0(7), \fB\s-1EVP_PKEY-X448\s0(7), and \s-1EVP_PKEY-ED25519\s0(7) pages.

\fBEVP_PKEY_fromdata_settable() gets a constant \s-1OSSL_PARAM\s0\|(3) array that describes the settable parameters that can be used with EVP_PKEY_fromdata(). \fIselection is described in \*(L"Selections\*(R".

Parameters in the params array that are not among the settable parameters for the given selection are ignored.

Subsection "Selections" The following constants can be used for selection: Item "EVP_PKEY_KEY_PARAMETERS" Only key parameters will be selected. Item "EVP_PKEY_PUBLIC_KEY" Only public key components will be selected. This includes optional key parameters. Item "EVP_PKEY_KEYPAIR" Any keypair components will be selected. This includes the private key, public key and key parameters. Header "NOTES" These functions only work with key management methods coming from a provider. This is the mirror function to EVP_PKEY_todata\|(3). Header "RETURN VALUES" \fBEVP_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. Header "EXAMPLES" 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 \fBBN_bn2nativepad(), but that's off topic here. Subsection "Creating an RSA keypair using raw key data" .Vb 1 #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| */ } .Ve Subsection "Creating an ECC keypair using raw key data" .Vb 3 #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); } .Ve Subsection "Finding out params for an unknown key type" .Vb 2 #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)\en"); else printf("(maximum size %zu)\en", settable_params->data_size); } } .Ve

The descriptor \s-1OSSL_PARAM\s0\|(3) returned by \fBEVP_PKEY_fromdata_settable() may also be used programmatically, for example with OSSL_PARAM_allocate_from_text\|(3).

Header "SEE ALSO" \fBEVP_PKEY_CTX_new\|(3), provider\|(7), EVP_PKEY_gettable_params\|(3), \s-1OSSL_PARAM\s0\|(3), EVP_PKEY_todata\|(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) Header "HISTORY" These functions were added in OpenSSL 3.0. Header "COPYRIGHT" Copyright 2019-2022 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>.