5 EVP_PKEY_CTX_get_params,
6 EVP_PKEY_CTX_gettable_params,
7 EVP_PKEY_CTX_set_params,
8 EVP_PKEY_CTX_settable_params,
10 EVP_PKEY_CTX_ctrl_str,
11 EVP_PKEY_CTX_ctrl_uint64,
13 EVP_PKEY_CTX_set_signature_md,
14 EVP_PKEY_CTX_get_signature_md,
15 EVP_PKEY_CTX_set_mac_key,
16 EVP_PKEY_CTX_set_rsa_padding,
17 EVP_PKEY_CTX_get_rsa_padding,
18 EVP_PKEY_CTX_set_rsa_pss_saltlen,
19 EVP_PKEY_CTX_get_rsa_pss_saltlen,
20 EVP_PKEY_CTX_set_rsa_keygen_bits,
21 EVP_PKEY_CTX_set_rsa_keygen_pubexp,
22 EVP_PKEY_CTX_set_rsa_keygen_primes,
23 EVP_PKEY_CTX_set_rsa_mgf1_md_name,
24 EVP_PKEY_CTX_set_rsa_mgf1_md,
25 EVP_PKEY_CTX_get_rsa_mgf1_md,
26 EVP_PKEY_CTX_get_rsa_mgf1_md_name,
27 EVP_PKEY_CTX_set_rsa_oaep_md_name,
28 EVP_PKEY_CTX_set_rsa_oaep_md,
29 EVP_PKEY_CTX_get_rsa_oaep_md,
30 EVP_PKEY_CTX_get_rsa_oaep_md_name,
31 EVP_PKEY_CTX_set0_rsa_oaep_label,
32 EVP_PKEY_CTX_get0_rsa_oaep_label,
33 EVP_PKEY_CTX_set_dsa_paramgen_bits,
34 EVP_PKEY_CTX_set_dsa_paramgen_q_bits,
35 EVP_PKEY_CTX_set_dsa_paramgen_md,
36 EVP_PKEY_CTX_set_dh_paramgen_prime_len,
37 EVP_PKEY_CTX_set_dh_paramgen_subprime_len,
38 EVP_PKEY_CTX_set_dh_paramgen_generator,
39 EVP_PKEY_CTX_set_dh_paramgen_type,
40 EVP_PKEY_CTX_set_dh_rfc5114,
41 EVP_PKEY_CTX_set_dhx_rfc5114,
42 EVP_PKEY_CTX_set_dh_pad,
43 EVP_PKEY_CTX_set_dh_nid,
44 EVP_PKEY_CTX_set_dh_kdf_type,
45 EVP_PKEY_CTX_get_dh_kdf_type,
46 EVP_PKEY_CTX_set0_dh_kdf_oid,
47 EVP_PKEY_CTX_get0_dh_kdf_oid,
48 EVP_PKEY_CTX_set_dh_kdf_md,
49 EVP_PKEY_CTX_get_dh_kdf_md,
50 EVP_PKEY_CTX_set_dh_kdf_outlen,
51 EVP_PKEY_CTX_get_dh_kdf_outlen,
52 EVP_PKEY_CTX_set0_dh_kdf_ukm,
53 EVP_PKEY_CTX_get0_dh_kdf_ukm,
54 EVP_PKEY_CTX_set_ec_paramgen_curve_nid,
55 EVP_PKEY_CTX_set_ec_param_enc,
56 EVP_PKEY_CTX_set_ecdh_cofactor_mode,
57 EVP_PKEY_CTX_get_ecdh_cofactor_mode,
58 EVP_PKEY_CTX_set_ecdh_kdf_type,
59 EVP_PKEY_CTX_get_ecdh_kdf_type,
60 EVP_PKEY_CTX_set_ecdh_kdf_md,
61 EVP_PKEY_CTX_get_ecdh_kdf_md,
62 EVP_PKEY_CTX_set_ecdh_kdf_outlen,
63 EVP_PKEY_CTX_get_ecdh_kdf_outlen,
64 EVP_PKEY_CTX_set0_ecdh_kdf_ukm,
65 EVP_PKEY_CTX_get0_ecdh_kdf_ukm,
66 EVP_PKEY_CTX_set1_id, EVP_PKEY_CTX_get1_id, EVP_PKEY_CTX_get1_id_len
67 - algorithm specific control operations
71 #include <openssl/evp.h>
73 int EVP_PKEY_CTX_get_params(EVP_PKEY_CTX *ctx, OSSL_PARAM *params);
74 const OSSL_PARAM *EVP_PKEY_CTX_gettable_params(EVP_PKEY_CTX *ctx);
75 int EVP_PKEY_CTX_set_params(EVP_PKEY_CTX *ctx, OSSL_PARAM *params);
76 const OSSL_PARAM *EVP_PKEY_CTX_settable_params(EVP_PKEY_CTX *ctx);
78 int EVP_PKEY_CTX_ctrl(EVP_PKEY_CTX *ctx, int keytype, int optype,
79 int cmd, int p1, void *p2);
80 int EVP_PKEY_CTX_ctrl_uint64(EVP_PKEY_CTX *ctx, int keytype, int optype,
81 int cmd, uint64_t value);
82 int EVP_PKEY_CTX_ctrl_str(EVP_PKEY_CTX *ctx, const char *type,
85 int EVP_PKEY_CTX_md(EVP_PKEY_CTX *ctx, int optype, int cmd, const char *md);
87 int EVP_PKEY_CTX_set_signature_md(EVP_PKEY_CTX *ctx, const EVP_MD *md);
88 int EVP_PKEY_CTX_get_signature_md(EVP_PKEY_CTX *ctx, const EVP_MD **pmd);
90 int EVP_PKEY_CTX_set_mac_key(EVP_PKEY_CTX *ctx, const unsigned char *key,
93 #include <openssl/rsa.h>
95 int EVP_PKEY_CTX_set_rsa_padding(EVP_PKEY_CTX *ctx, int pad);
96 int EVP_PKEY_CTX_get_rsa_padding(EVP_PKEY_CTX *ctx, int *pad);
97 int EVP_PKEY_CTX_set_rsa_pss_saltlen(EVP_PKEY_CTX *ctx, int saltlen);
98 int EVP_PKEY_CTX_get_rsa_pss_saltlen(EVP_PKEY_CTX *ctx, int *saltlen);
99 int EVP_PKEY_CTX_set_rsa_keygen_bits(EVP_PKEY_CTX *ctx, int mbits);
100 int EVP_PKEY_CTX_set_rsa_keygen_pubexp(EVP_PKEY_CTX *ctx, BIGNUM *pubexp);
101 int EVP_PKEY_CTX_set_rsa_keygen_primes(EVP_PKEY_CTX *ctx, int primes);
102 int EVP_PKEY_CTX_set_rsa_mgf1_md_name(EVP_PKEY_CTX *ctx, const char *mdname,
103 const char *mdprops);
104 int EVP_PKEY_CTX_set_rsa_mgf1_md(EVP_PKEY_CTX *ctx, const EVP_MD *md);
105 int EVP_PKEY_CTX_get_rsa_mgf1_md(EVP_PKEY_CTX *ctx, const EVP_MD **md);
106 int EVP_PKEY_CTX_get_rsa_mgf1_md_name(EVP_PKEY_CTX *ctx, char *name,
108 int EVP_PKEY_CTX_set_rsa_oaep_md_name(EVP_PKEY_CTX *ctx, const char *mdname,
109 const char *mdprops);
110 int EVP_PKEY_CTX_set_rsa_oaep_md(EVP_PKEY_CTX *ctx, const EVP_MD *md);
111 int EVP_PKEY_CTX_get_rsa_oaep_md(EVP_PKEY_CTX *ctx, const EVP_MD **md);
112 int EVP_PKEY_CTX_get_rsa_oaep_md_name(EVP_PKEY_CTX *ctx, char *name,
114 int EVP_PKEY_CTX_set0_rsa_oaep_label(EVP_PKEY_CTX *ctx, unsigned char *label, int len);
115 int EVP_PKEY_CTX_get0_rsa_oaep_label(EVP_PKEY_CTX *ctx, unsigned char **label);
117 #include <openssl/dsa.h>
119 int EVP_PKEY_CTX_set_dsa_paramgen_bits(EVP_PKEY_CTX *ctx, int nbits);
120 int EVP_PKEY_CTX_set_dsa_paramgen_q_bits(EVP_PKEY_CTX *ctx, int qbits);
121 int EVP_PKEY_CTX_set_dsa_paramgen_md(EVP_PKEY_CTX *ctx, const EVP_MD *md);
123 #include <openssl/dh.h>
125 int EVP_PKEY_CTX_set_dh_paramgen_prime_len(EVP_PKEY_CTX *ctx, int len);
126 int EVP_PKEY_CTX_set_dh_paramgen_subprime_len(EVP_PKEY_CTX *ctx, int len);
127 int EVP_PKEY_CTX_set_dh_paramgen_generator(EVP_PKEY_CTX *ctx, int gen);
128 int EVP_PKEY_CTX_set_dh_paramgen_type(EVP_PKEY_CTX *ctx, int type);
129 int EVP_PKEY_CTX_set_dh_pad(EVP_PKEY_CTX *ctx, int pad);
130 int EVP_PKEY_CTX_set_dh_nid(EVP_PKEY_CTX *ctx, int nid);
131 int EVP_PKEY_CTX_set_dh_rfc5114(EVP_PKEY_CTX *ctx, int rfc5114);
132 int EVP_PKEY_CTX_set_dhx_rfc5114(EVP_PKEY_CTX *ctx, int rfc5114);
133 int EVP_PKEY_CTX_set_dh_kdf_type(EVP_PKEY_CTX *ctx, int kdf);
134 int EVP_PKEY_CTX_get_dh_kdf_type(EVP_PKEY_CTX *ctx);
135 int EVP_PKEY_CTX_set0_dh_kdf_oid(EVP_PKEY_CTX *ctx, ASN1_OBJECT *oid);
136 int EVP_PKEY_CTX_get0_dh_kdf_oid(EVP_PKEY_CTX *ctx, ASN1_OBJECT **oid);
137 int EVP_PKEY_CTX_set_dh_kdf_md(EVP_PKEY_CTX *ctx, const EVP_MD *md);
138 int EVP_PKEY_CTX_get_dh_kdf_md(EVP_PKEY_CTX *ctx, const EVP_MD **md);
139 int EVP_PKEY_CTX_set_dh_kdf_outlen(EVP_PKEY_CTX *ctx, int len);
140 int EVP_PKEY_CTX_get_dh_kdf_outlen(EVP_PKEY_CTX *ctx, int *len);
141 int EVP_PKEY_CTX_set0_dh_kdf_ukm(EVP_PKEY_CTX *ctx, unsigned char *ukm, int len);
142 int EVP_PKEY_CTX_get0_dh_kdf_ukm(EVP_PKEY_CTX *ctx, unsigned char **ukm);
144 #include <openssl/ec.h>
146 int EVP_PKEY_CTX_set_ec_paramgen_curve_nid(EVP_PKEY_CTX *ctx, int nid);
147 int EVP_PKEY_CTX_set_ec_param_enc(EVP_PKEY_CTX *ctx, int param_enc);
148 int EVP_PKEY_CTX_set_ecdh_cofactor_mode(EVP_PKEY_CTX *ctx, int cofactor_mode);
149 int EVP_PKEY_CTX_get_ecdh_cofactor_mode(EVP_PKEY_CTX *ctx);
150 int EVP_PKEY_CTX_set_ecdh_kdf_type(EVP_PKEY_CTX *ctx, int kdf);
151 int EVP_PKEY_CTX_get_ecdh_kdf_type(EVP_PKEY_CTX *ctx);
152 int EVP_PKEY_CTX_set_ecdh_kdf_md(EVP_PKEY_CTX *ctx, const EVP_MD *md);
153 int EVP_PKEY_CTX_get_ecdh_kdf_md(EVP_PKEY_CTX *ctx, const EVP_MD **md);
154 int EVP_PKEY_CTX_set_ecdh_kdf_outlen(EVP_PKEY_CTX *ctx, int len);
155 int EVP_PKEY_CTX_get_ecdh_kdf_outlen(EVP_PKEY_CTX *ctx, int *len);
156 int EVP_PKEY_CTX_set0_ecdh_kdf_ukm(EVP_PKEY_CTX *ctx, unsigned char *ukm, int len);
157 int EVP_PKEY_CTX_get0_ecdh_kdf_ukm(EVP_PKEY_CTX *ctx, unsigned char **ukm);
159 int EVP_PKEY_CTX_set1_id(EVP_PKEY_CTX *ctx, void *id, size_t id_len);
160 int EVP_PKEY_CTX_get1_id(EVP_PKEY_CTX *ctx, void *id);
161 int EVP_PKEY_CTX_get1_id_len(EVP_PKEY_CTX *ctx, size_t *id_len);
165 The EVP_PKEY_CTX_get_params() and EVP_PKEY_CTX_set_params() functions get and
166 send arbitrary parameters from and to the algorithm implementation respectively.
167 Not all parameters may be supported by all providers.
168 See L<OSSL_PROVIDER(3)> for more information on providers.
169 See L<OSSL_PARAM(3)> for more information on parameters.
170 These functions must only be called after the EVP_PKEY_CTX has been initialised
171 for use in an operation.
173 The parameters currently supported by the default provider are:
177 =item "pad" (B<OSSL_EXCHANGE_PARAM_PAD>) <unsigned integer>
179 Sets the DH padding mode.
180 If B<OSSL_EXCHANGE_PARAM_PAD> is 1 then the shared secret is padded with zeros
181 up to the size of the DH prime B<p>.
182 If B<OSSL_EXCHANGE_PARAM_PAD> is zero (the default) then no padding is
185 =item "digest" (B<OSSL_SIGNATURE_PARAM_DIGEST>) <UTF8 string>
187 Gets and sets the name of the digest algorithm used for the input to the
190 =item "digest-size" (B<OSSL_SIGNATURE_PARAM_DIGEST_SIZE>) <unsigned integer>
192 Gets and sets the output size of the digest algorithm used for the input to the
194 The length of the "digest-size" parameter should not exceed that of a B<size_t>.
195 The internal algorithm that supports this parameter is DSA.
199 EVP_PKEY_CTX_gettable_params() and EVP_PKEY_CTX_settable_params() gets a
200 constant B<OSSL_PARAM> array that describes the gettable and
201 settable parameters for the current algorithm implementation, i.e. parameters
202 that can be used with EVP_PKEY_CTX_get_params() and EVP_PKEY_CTX_set_params()
204 See L<OSSL_PARAM(3)> for the use of B<OSSL_PARAM> as parameter descriptor.
205 These functions must only be called after the EVP_PKEY_CTX has been initialised
206 for use in an operation.
208 The function EVP_PKEY_CTX_ctrl() sends a control operation to the context
209 B<ctx>. The key type used must match B<keytype> if it is not -1. The parameter
210 B<optype> is a mask indicating which operations the control can be applied to.
211 The control command is indicated in B<cmd> and any additional arguments in
214 For I<cmd> = B<EVP_PKEY_CTRL_SET_MAC_KEY>, I<p1> is the length of the MAC key,
215 and I<p2> is the MAC key. This is used by Poly1305, SipHash, HMAC and CMAC.
217 Applications will not normally call EVP_PKEY_CTX_ctrl() directly but will
218 instead call one of the algorithm specific macros below.
220 The function EVP_PKEY_CTX_ctrl_uint64() is a wrapper that directly passes a
221 uint64 value as B<p2> to EVP_PKEY_CTX_ctrl().
223 The function EVP_PKEY_CTX_ctrl_str() allows an application to send an algorithm
224 specific control operation to a context B<ctx> in string form. This is
225 intended to be used for options specified on the command line or in text
226 files. The commands supported are documented in the openssl utility
227 command line pages for the option B<-pkeyopt> which is supported by the
228 B<pkeyutl>, B<genpkey> and B<req> commands.
230 The function EVP_PKEY_CTX_md() sends a message digest control operation
231 to the context B<ctx>. The message digest is specified by its name B<md>.
233 The EVP_PKEY_CTX_set_signature_md() function sets the message digest type used
234 in a signature. It can be used in the RSA, DSA and ECDSA algorithms.
236 The EVP_PKEY_CTX_get_signature_md() function gets the message digest type used
237 in a signature. It can be used in the RSA, DSA and ECDSA algorithms.
239 All the remaining "functions" are implemented as macros.
241 Key generation typically involves setting up parameters to be used and
242 generating the private and public key data. Some algorithm implementations
243 allow private key data to be set explicitly using the EVP_PKEY_CTX_set_mac_key()
244 macro. In this case key generation is simply the process of setting up the
245 parameters for the key and then setting the raw key data to the value explicitly
246 provided by that macro. Normally applications would call
247 L<EVP_PKEY_new_raw_private_key(3)> or similar functions instead of this macro.
249 The EVP_PKEY_CTX_set_mac_key() macro can be used with any of the algorithms
250 supported by the L<EVP_PKEY_new_raw_private_key(3)> function.
252 =head2 RSA parameters
254 The EVP_PKEY_CTX_set_rsa_padding() function sets the RSA padding mode for B<ctx>.
255 The B<pad> parameter can take the value B<RSA_PKCS1_PADDING> for PKCS#1
256 padding, B<RSA_SSLV23_PADDING> for SSLv23 padding, B<RSA_NO_PADDING> for
257 no padding, B<RSA_PKCS1_OAEP_PADDING> for OAEP padding (encrypt and
258 decrypt only), B<RSA_X931_PADDING> for X9.31 padding (signature operations
259 only), B<RSA_PKCS1_PSS_PADDING> (sign and verify only) and
260 B<RSA_PKCS1_WITH_TLS_PADDING> for TLS RSA ClientKeyExchange message padding
263 Two RSA padding modes behave differently if EVP_PKEY_CTX_set_signature_md()
264 is used. If this macro is called for PKCS#1 padding the plaintext buffer is
265 an actual digest value and is encapsulated in a DigestInfo structure according
266 to PKCS#1 when signing and this structure is expected (and stripped off) when
267 verifying. If this control is not used with RSA and PKCS#1 padding then the
268 supplied data is used directly and not encapsulated. In the case of X9.31
269 padding for RSA the algorithm identifier byte is added or checked and removed
270 if this control is called. If it is not called then the first byte of the plaintext
271 buffer is expected to be the algorithm identifier byte.
273 The EVP_PKEY_CTX_get_rsa_padding() function gets the RSA padding mode for B<ctx>.
275 The EVP_PKEY_CTX_set_rsa_pss_saltlen() function sets the RSA PSS salt
276 length to I<saltlen>. As its name implies it is only supported for PSS
277 padding. If this function is not called then the maximum salt length
278 is used when signing and auto detection when verifying. Three special
279 values are supported:
283 =item B<RSA_PSS_SALTLEN_DIGEST>
285 sets the salt length to the digest length.
287 =item B<RSA_PSS_SALTLEN_MAX>
289 sets the salt length to the maximum permissible value.
291 =item B<RSA_PSS_SALTLEN_AUTO>
293 causes the salt length to be automatically determined based on the
294 B<PSS> block structure when verifying. When signing, it has the same
295 meaning as B<RSA_PSS_SALTLEN_MAX>.
299 The EVP_PKEY_CTX_get_rsa_pss_saltlen() function gets the RSA PSS salt length
300 for B<ctx>. The padding mode must already have been set to
301 B<RSA_PKCS1_PSS_PADDING>.
303 The EVP_PKEY_CTX_set_rsa_keygen_bits() macro sets the RSA key length for
304 RSA key generation to I<bits>. If not specified 2048 bits is used.
306 The EVP_PKEY_CTX_set_rsa_keygen_pubexp() macro sets the public exponent value
307 for RSA key generation to B<pubexp>. Currently it should be an odd integer. The
308 B<pubexp> pointer is used internally by this function so it should not be
309 modified or freed after the call. If not specified 65537 is used.
311 The EVP_PKEY_CTX_set_rsa_keygen_primes() macro sets the number of primes for
312 RSA key generation to B<primes>. If not specified 2 is used.
314 The EVP_PKEY_CTX_set_rsa_mgf1_md_name() function sets the MGF1 digest for RSA
315 padding schemes to the digest named B<mdname>. If the RSA algorithm
316 implementation for the selected provider supports it then the digest will be
317 fetched using the properties B<mdprops>. If not explicitly set the signing
318 digest is used. The padding mode must have been set to B<RSA_PKCS1_OAEP_PADDING>
319 or B<RSA_PKCS1_PSS_PADDING>.
321 The EVP_PKEY_CTX_set_rsa_mgf1_md() function does the same as
322 EVP_PKEY_CTX_set_rsa_mgf1_md_name() except that the name of the digest is
323 inferred from the supplied B<md> and it is not possible to specify any
326 The EVP_PKEY_CTX_get_rsa_mgf1_md_name() function gets the name of the MGF1
327 digest algorithm for B<ctx>. If not explicitly set the signing digest is used.
328 The padding mode must have been set to B<RSA_PKCS1_OAEP_PADDING> or
329 B<RSA_PKCS1_PSS_PADDING>.
331 The EVP_PKEY_CTX_get_rsa_mgf1_md() function does the same as
332 EVP_PKEY_CTX_get_rsa_mgf1_md_name() except that it returns a pointer to an
333 EVP_MD object instead. Note that only known, built-in EVP_MD objects will be
334 returned. The EVP_MD object may be NULL if the digest is not one of these (such
335 as a digest only implemented in a third party provider).
337 The EVP_PKEY_CTX_set_rsa_oaep_md_name() function sets the message digest type
338 used in RSA OAEP to the digest named B<mdname>. If the RSA algorithm
339 implementation for the selected provider supports it then the digest will be
340 fetched using the properties B<mdprops>. The padding mode must have been set to
341 B<RSA_PKCS1_OAEP_PADDING>.
343 The EVP_PKEY_CTX_set_rsa_oaep_md() function does the same as
344 EVP_PKEY_CTX_set_rsa_oaep_md_name() except that the name of the digest is
345 inferred from the supplied B<md> and it is not possible to specify any
348 The EVP_PKEY_CTX_get_rsa_oaep_md_name() function gets the message digest
349 algorithm name used in RSA OAEP and stores it in the buffer B<name> which is of
350 size B<namelen>. The padding mode must have been set to
351 B<RSA_PKCS1_OAEP_PADDING>. The buffer should be sufficiently large for any
352 expected digest algorithm names or the function will fail.
354 The EVP_PKEY_CTX_get_rsa_oaep_md() function does the same as
355 EVP_PKEY_CTX_get_rsa_oaep_md_name() except that it returns a pointer to an
356 EVP_MD object instead. Note that only known, built-in EVP_MD objects will be
357 returned. The EVP_MD object may be NULL if the digest is not one of these (such
358 as a digest only implemented in a third party provider).
360 The EVP_PKEY_CTX_set0_rsa_oaep_label() function sets the RSA OAEP label to
361 B<label> and its length to B<len>. If B<label> is NULL or B<len> is 0,
362 the label is cleared. The library takes ownership of the label so the
363 caller should not free the original memory pointed to by B<label>.
364 The padding mode must have been set to B<RSA_PKCS1_OAEP_PADDING>.
366 The EVP_PKEY_CTX_get0_rsa_oaep_label() function gets the RSA OAEP label to
367 B<label>. The return value is the label length. The padding mode
368 must have been set to B<RSA_PKCS1_OAEP_PADDING>. The resulting pointer is owned
369 by the library and should not be freed by the caller.
371 B<RSA_PKCS1_WITH_TLS_PADDING> is used when decrypting an RSA encrypted TLS
372 pre-master secret in a TLS ClientKeyExchange message. It is the same as
373 RSA_PKCS1_PADDING except that it additionally verifies that the result is the
374 correct length and the first two bytes are the protocol version initially
375 requested by the client. If the encrypted content is publicly invalid then the
376 decryption will fail. However, if the padding checks fail then decryption will
377 still appear to succeed but a random TLS premaster secret will be returned
378 instead. This padding mode accepts two parameters which can be set using the
379 L<EVP_PKEY_CTX_set_params(3)> function. These are
380 OSSL_ASYM_CIPHER_PARAM_TLS_CLIENT_VERSION and
381 OSSL_ASYM_CIPHER_PARAM_TLS_NEGOTIATED_VERSION, both of which are expected to be
382 unsigned integers. Normally only the first of these will be set and represents
383 the TLS protocol version that was first requested by the client (e.g. 0x0303 for
384 TLSv1.2, 0x0302 for TLSv1.1 etc). Historically some buggy clients would use the
385 negotiated protocol version instead of the protocol version first requested. If
386 this behaviour should be tolerated then
387 OSSL_ASYM_CIPHER_PARAM_TLS_NEGOTIATED_VERSION should be set to the actual
388 negotiated protocol version. Otherwise it should be left unset.
390 =head2 DSA parameters
392 The EVP_PKEY_CTX_set_dsa_paramgen_bits() macro sets the number of bits used
393 for DSA parameter generation to I<nbits>. If not specified, 2048 is used.
395 The EVP_PKEY_CTX_set_dsa_paramgen_q_bits() macro sets the number of bits in the
396 subprime parameter I<q> for DSA parameter generation to I<qbits>. If not
397 specified, 224 is used. If a digest function is specified below, this parameter
398 is ignored and instead, the number of bits in I<q> matches the size of the
401 The EVP_PKEY_CTX_set_dsa_paramgen_md() macro sets the digest function used for
402 DSA parameter generation to B<md>. If not specified, one of SHA-1, SHA-224, or
403 SHA-256 is selected to match the bit length of B<q> above.
407 The EVP_PKEY_CTX_set_dh_paramgen_prime_len() macro sets the length of the DH
408 prime parameter B<p> for DH parameter generation. If this macro is not called
409 then 2048 is used. Only accepts lengths greater than or equal to 256.
411 The EVP_PKEY_CTX_set_dh_paramgen_subprime_len() macro sets the length of the DH
412 optional subprime parameter B<q> for DH parameter generation. The default is
413 256 if the prime is at least 2048 bits long or 160 otherwise. The DH
414 paramgen type must have been set to B<DH_PARAMGEN_TYPE_FIPS_186_2> or
415 B<DH_PARAMGEN_TYPE_FIPS_186_4>.
417 The EVP_PKEY_CTX_set_dh_paramgen_generator() macro sets DH generator to B<gen>
418 for DH parameter generation. If not specified 2 is used.
420 The EVP_PKEY_CTX_set_dh_paramgen_type() macro sets the key type for DH
421 parameter generation. The supported parameters are:
425 =item B<DH_PARAMGEN_TYPE_GENERATOR>
427 Uses a generator g (PKCS#3 format).
429 =item B<DH_PARAMGEN_TYPE_FIPS_186_2>
431 FIPS186-2 FFC parameter generator (X9.42 DH).
433 =item B<DH_PARAMGEN_TYPE_FIPS_186_4>
435 FIPS186-4 FFC parameter generator.
439 The default is B<DH_PARAMGEN_TYPE_GENERATOR>.
441 The EVP_PKEY_CTX_set_dh_pad() function sets the DH padding mode.
442 If B<pad> is 1 the shared secret is padded with zeros up to the size of the DH
444 If B<pad> is zero (the default) then no padding is performed.
446 EVP_PKEY_CTX_set_dh_nid() sets the DH parameters to values corresponding to
447 B<nid> as defined in RFC7919 or RFC3526. The B<nid> parameter must be
448 B<NID_ffdhe2048>, B<NID_ffdhe3072>, B<NID_ffdhe4096>, B<NID_ffdhe6144>,
449 B<NID_ffdhe8192>, B<NID_modp_1536>, B<NID_modp_2048>, B<NID_modp_3072>,
450 B<NID_modp_4096>, B<NID_modp_6144>, B<NID_modp_8192> or B<NID_undef> to clear
451 the stored value. This macro can be called during parameter or key generation.
452 The nid parameter and the rfc5114 parameter are mutually exclusive.
454 The EVP_PKEY_CTX_set_dh_rfc5114() and EVP_PKEY_CTX_set_dhx_rfc5114() macros are
455 synonymous. They set the DH parameters to the values defined in RFC5114. The
456 B<rfc5114> parameter must be 1, 2 or 3 corresponding to RFC5114 sections
457 2.1, 2.2 and 2.3. or 0 to clear the stored value. This macro can be called
458 during parameter generation. The B<ctx> must have a key type of
460 The rfc5114 parameter and the nid parameter are mutually exclusive.
462 =head2 DH key derivation function parameters
464 Note that all of the following functions require that the B<ctx> parameter has
465 a private key type of B<EVP_PKEY_DHX>. When using key derivation, the output of
466 EVP_PKEY_derive() is the output of the KDF instead of the DH shared secret.
467 The KDF output is typically used as a Key Encryption Key (KEK) that in turn
468 encrypts a Content Encryption Key (CEK).
470 The EVP_PKEY_CTX_set_dh_kdf_type() macro sets the key derivation function type
471 to B<kdf> for DH key derivation. Possible values are B<EVP_PKEY_DH_KDF_NONE>
472 and B<EVP_PKEY_DH_KDF_X9_42> which uses the key derivation specified in RFC2631
473 (based on the keying algorithm described in X9.42). When using key derivation,
474 the B<kdf_oid>, B<kdf_md> and B<kdf_outlen> parameters must also be specified.
476 The EVP_PKEY_CTX_get_dh_kdf_type() macro gets the key derivation function type
477 for B<ctx> used for DH key derivation. Possible values are B<EVP_PKEY_DH_KDF_NONE>
478 and B<EVP_PKEY_DH_KDF_X9_42>.
480 The EVP_PKEY_CTX_set0_dh_kdf_oid() macro sets the key derivation function
481 object identifier to B<oid> for DH key derivation. This OID should identify
482 the algorithm to be used with the Content Encryption Key.
483 The library takes ownership of the object identifier so the caller should not
484 free the original memory pointed to by B<oid>.
486 The EVP_PKEY_CTX_get0_dh_kdf_oid() macro gets the key derivation function oid
487 for B<ctx> used for DH key derivation. The resulting pointer is owned by the
488 library and should not be freed by the caller.
490 The EVP_PKEY_CTX_set_dh_kdf_md() macro sets the key derivation function
491 message digest to B<md> for DH key derivation. Note that RFC2631 specifies
492 that this digest should be SHA1 but OpenSSL tolerates other digests.
494 The EVP_PKEY_CTX_get_dh_kdf_md() macro gets the key derivation function
495 message digest for B<ctx> used for DH key derivation.
497 The EVP_PKEY_CTX_set_dh_kdf_outlen() macro sets the key derivation function
498 output length to B<len> for DH key derivation.
500 The EVP_PKEY_CTX_get_dh_kdf_outlen() macro gets the key derivation function
501 output length for B<ctx> used for DH key derivation.
503 The EVP_PKEY_CTX_set0_dh_kdf_ukm() macro sets the user key material to
504 B<ukm> and its length to B<len> for DH key derivation. This parameter is optional
505 and corresponds to the partyAInfo field in RFC2631 terms. The specification
506 requires that it is 512 bits long but this is not enforced by OpenSSL.
507 The library takes ownership of the user key material so the caller should not
508 free the original memory pointed to by B<ukm>.
510 The EVP_PKEY_CTX_get0_dh_kdf_ukm() macro gets the user key material for B<ctx>.
511 The return value is the user key material length. The resulting pointer is owned
512 by the library and should not be freed by the caller.
516 The EVP_PKEY_CTX_set_ec_paramgen_curve_nid() sets the EC curve for EC parameter
517 generation to B<nid>. For EC parameter generation this macro must be called
518 or an error occurs because there is no default curve.
519 This function can also be called to set the curve explicitly when
520 generating an EC key.
522 The EVP_PKEY_CTX_set_ec_param_enc() macro sets the EC parameter encoding to
523 B<param_enc> when generating EC parameters or an EC key. The encoding can be
524 B<OPENSSL_EC_EXPLICIT_CURVE> for explicit parameters (the default in versions
525 of OpenSSL before 1.1.0) or B<OPENSSL_EC_NAMED_CURVE> to use named curve form.
526 For maximum compatibility the named curve form should be used. Note: the
527 B<OPENSSL_EC_NAMED_CURVE> value was added in OpenSSL 1.1.0; previous
528 versions should use 0 instead.
530 =head2 ECDH parameters
532 The EVP_PKEY_CTX_set_ecdh_cofactor_mode() macro sets the cofactor mode to
533 B<cofactor_mode> for ECDH key derivation. Possible values are 1 to enable
534 cofactor key derivation, 0 to disable it and -1 to clear the stored cofactor
535 mode and fallback to the private key cofactor mode.
537 The EVP_PKEY_CTX_get_ecdh_cofactor_mode() macro returns the cofactor mode for
538 B<ctx> used for ECDH key derivation. Possible values are 1 when cofactor key
539 derivation is enabled and 0 otherwise.
541 =head2 ECDH key derivation function parameters
543 The EVP_PKEY_CTX_set_ecdh_kdf_type() macro sets the key derivation function type
544 to B<kdf> for ECDH key derivation. Possible values are B<EVP_PKEY_ECDH_KDF_NONE>
545 and B<EVP_PKEY_ECDH_KDF_X9_63> which uses the key derivation specified in X9.63.
546 When using key derivation, the B<kdf_md> and B<kdf_outlen> parameters must
549 The EVP_PKEY_CTX_get_ecdh_kdf_type() macro returns the key derivation function
550 type for B<ctx> used for ECDH key derivation. Possible values are
551 B<EVP_PKEY_ECDH_KDF_NONE> and B<EVP_PKEY_ECDH_KDF_X9_63>.
553 The EVP_PKEY_CTX_set_ecdh_kdf_md() macro sets the key derivation function
554 message digest to B<md> for ECDH key derivation. Note that X9.63 specifies
555 that this digest should be SHA1 but OpenSSL tolerates other digests.
557 The EVP_PKEY_CTX_get_ecdh_kdf_md() macro gets the key derivation function
558 message digest for B<ctx> used for ECDH key derivation.
560 The EVP_PKEY_CTX_set_ecdh_kdf_outlen() macro sets the key derivation function
561 output length to B<len> for ECDH key derivation.
563 The EVP_PKEY_CTX_get_ecdh_kdf_outlen() macro gets the key derivation function
564 output length for B<ctx> used for ECDH key derivation.
566 The EVP_PKEY_CTX_set0_ecdh_kdf_ukm() macro sets the user key material to B<ukm>
567 for ECDH key derivation. This parameter is optional and corresponds to the
568 shared info in X9.63 terms. The library takes ownership of the user key material
569 so the caller should not free the original memory pointed to by B<ukm>.
571 The EVP_PKEY_CTX_get0_ecdh_kdf_ukm() macro gets the user key material for B<ctx>.
572 The return value is the user key material length. The resulting pointer is owned
573 by the library and should not be freed by the caller.
575 =head2 Other parameters
577 The EVP_PKEY_CTX_set1_id(), EVP_PKEY_CTX_get1_id() and EVP_PKEY_CTX_get1_id_len()
578 macros are used to manipulate the special identifier field for specific signature
579 algorithms such as SM2. The EVP_PKEY_CTX_set1_id() sets an ID pointed by B<id> with
580 the length B<id_len> to the library. The library takes a copy of the id so that
581 the caller can safely free the original memory pointed to by B<id>. The
582 EVP_PKEY_CTX_get1_id_len() macro returns the length of the ID set via a previous
583 call to EVP_PKEY_CTX_set1_id(). The length is usually used to allocate adequate
584 memory for further calls to EVP_PKEY_CTX_get1_id(). The EVP_PKEY_CTX_get1_id()
585 macro returns the previously set ID value to caller in B<id>. The caller should
586 allocate adequate memory space for the B<id> before calling EVP_PKEY_CTX_get1_id().
590 EVP_PKEY_CTX_set_params() returns 1 for success or 0 otherwise.
591 EVP_PKEY_CTX_settable_params() returns an OSSL_PARAM array on success or NULL on
593 It may also return NULL if there are no settable parameters available.
595 All other functions and macros described on this page return a positive value
596 for success and 0 or a negative value for failure. In particular a return value
597 of -2 indicates the operation is not supported by the public key algorithm.
601 L<EVP_PKEY_CTX_new(3)>,
602 L<EVP_PKEY_encrypt(3)>,
603 L<EVP_PKEY_decrypt(3)>,
605 L<EVP_PKEY_verify(3)>,
606 L<EVP_PKEY_verify_recover(3)>,
607 L<EVP_PKEY_derive(3)>,
608 L<EVP_PKEY_keygen(3)>
612 EVP_PKEY_CTX_get_signature_md(), EVP_PKEY_CTX_set_signature_md(),
613 EVP_PKEY_CTX_set_dh_pad(), EVP_PKEY_CTX_set_rsa_padding(),
614 EVP_PKEY_CTX_get_rsa_padding(), EVP_PKEY_CTX_get_rsa_mgf1_md(),
615 EVP_PKEY_CTX_set_rsa_mgf1_md(), EVP_PKEY_CTX_set_rsa_oaep_md(),
616 EVP_PKEY_CTX_get_rsa_oaep_md(), EVP_PKEY_CTX_set0_rsa_oaep_label(),
617 EVP_PKEY_CTX_get0_rsa_oaep_label(), EVP_PKEY_CTX_set_rsa_pss_saltlen(),
618 EVP_PKEY_CTX_get_rsa_pss_saltlen(), were macros in OpenSSL 1.1.1 and below.
619 From OpenSSL 3.0 they are functions.
621 EVP_PKEY_CTX_get_rsa_oaep_md_name(), EVP_PKEY_CTX_get_rsa_mgf1_md_name(),
622 EVP_PKEY_CTX_set_rsa_mgf1_md_name() and EVP_PKEY_CTX_set_rsa_oaep_md_name() were
623 added in OpenSSL 3.0.
625 The EVP_PKEY_CTX_set1_id(), EVP_PKEY_CTX_get1_id() and
626 EVP_PKEY_CTX_get1_id_len() macros were added in 1.1.1, other functions were
627 added in OpenSSL 1.0.0.
631 Copyright 2006-2018 The OpenSSL Project Authors. All Rights Reserved.
633 Licensed under the Apache License 2.0 (the "License"). You may not use
634 this file except in compliance with the License. You can obtain a copy
635 in the file LICENSE in the source distribution or at
636 L<https://www.openssl.org/source/license.html>.