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 len);
98 int EVP_PKEY_CTX_get_rsa_pss_saltlen(EVP_PKEY_CTX *ctx, int *len);
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 (for example by L<EVP_PKEY_sign_init_ex(3)>,
172 L<EVP_PKEY_derive_init_ex(3)> or other similar functions).
174 The parameters currently supported by the default provider are:
178 =item "pad" (B<OSSL_EXCHANGE_PARAM_PAD>) <unsigned integer>
180 Sets the DH padding mode.
181 If B<OSSL_EXCHANGE_PARAM_PAD> is 1 then the shared secret is padded with zeros
182 up to the size of the DH prime B<p>.
183 If B<OSSL_EXCHANGE_PARAM_PAD> is zero (the default) then no padding is
186 =item "digest" (B<OSSL_SIGNATURE_PARAM_DIGEST>) <UTF8 string>
188 Gets and sets the name of the digest algorithm used for the input to the
191 =item "digest-size" (B<OSSL_SIGNATURE_PARAM_DIGEST_SIZE>) <unsigned integer>
193 Gets and sets the output size of the digest algorithm used for the input to the
195 The length of the "digest-size" parameter should not exceed that of a B<size_t>.
196 The internal algorithm that supports this parameter is DSA.
200 EVP_PKEY_CTX_gettable_params() and EVP_PKEY_CTX_settable_params() gets a
201 constant B<OSSL_PARAM> array that describes the gettable and
202 settable parameters for the current algorithm implementation, i.e. parameters
203 that can be used with EVP_PKEY_CTX_get_params() and EVP_PKEY_CTX_set_params()
205 See L<OSSL_PARAM(3)> for the use of B<OSSL_PARAM> as parameter descriptor.
206 These functions must only be called after the EVP_PKEY_CTX has been initialised
207 for use in an operation (for example by L<EVP_PKEY_sign_init_ex(3)>,
208 L<EVP_PKEY_derive_init_ex(3)> or other similar functions).
210 The function EVP_PKEY_CTX_ctrl() sends a control operation to the context
211 B<ctx>. The key type used must match B<keytype> if it is not -1. The parameter
212 B<optype> is a mask indicating which operations the control can be applied to.
213 The control command is indicated in B<cmd> and any additional arguments in
216 For B<cmd> = B<EVP_PKEY_CTRL_SET_MAC_KEY>, B<p1> is the length of the MAC key,
217 and B<p2> is MAC key. This is used by Poly1305, SipHash, HMAC and CMAC.
219 Applications will not normally call EVP_PKEY_CTX_ctrl() directly but will
220 instead call one of the algorithm specific macros below.
222 The function EVP_PKEY_CTX_ctrl_uint64() is a wrapper that directly passes a
223 uint64 value as B<p2> to EVP_PKEY_CTX_ctrl().
225 The function EVP_PKEY_CTX_ctrl_str() allows an application to send an algorithm
226 specific control operation to a context B<ctx> in string form. This is
227 intended to be used for options specified on the command line or in text
228 files. The commands supported are documented in the openssl utility
229 command line pages for the option B<-pkeyopt> which is supported by the
230 B<pkeyutl>, B<genpkey> and B<req> commands.
232 The function EVP_PKEY_CTX_md() sends a message digest control operation
233 to the context B<ctx>. The message digest is specified by its name B<md>.
235 The EVP_PKEY_CTX_set_signature_md() function sets the message digest type used
236 in a signature. It can be used in the RSA, DSA and ECDSA algorithms.
238 The EVP_PKEY_CTX_get_signature_md() function gets the message digest type used
239 in a signature. It can be used in the RSA, DSA and ECDSA algorithms.
241 All the remaining "functions" are implemented as macros.
243 Key generation typically involves setting up parameters to be used and
244 generating the private and public key data. Some algorithm implementations
245 allow private key data to be set explicitly using the EVP_PKEY_CTX_set_mac_key()
246 macro. In this case key generation is simply the process of setting up the
247 parameters for the key and then setting the raw key data to the value explicitly
248 provided by that macro. Normally applications would call
249 L<EVP_PKEY_new_raw_private_key(3)> or similar functions instead of this macro.
251 The EVP_PKEY_CTX_set_mac_key() macro can be used with any of the algorithms
252 supported by the L<EVP_PKEY_new_raw_private_key(3)> function.
254 =head2 RSA parameters
256 The EVP_PKEY_CTX_set_rsa_padding() function sets the RSA padding mode for B<ctx>.
257 The B<pad> parameter can take the value B<RSA_PKCS1_PADDING> for PKCS#1
258 padding, B<RSA_SSLV23_PADDING> for SSLv23 padding, B<RSA_NO_PADDING> for
259 no padding, B<RSA_PKCS1_OAEP_PADDING> for OAEP padding (encrypt and
260 decrypt only), B<RSA_X931_PADDING> for X9.31 padding (signature operations
261 only), B<RSA_PKCS1_PSS_PADDING> (sign and verify only) and
262 B<RSA_PKCS1_WITH_TLS_PADDING> for TLS RSA ClientKeyExchange message padding
265 Two RSA padding modes behave differently if EVP_PKEY_CTX_set_signature_md()
266 is used. If this macro is called for PKCS#1 padding the plaintext buffer is
267 an actual digest value and is encapsulated in a DigestInfo structure according
268 to PKCS#1 when signing and this structure is expected (and stripped off) when
269 verifying. If this control is not used with RSA and PKCS#1 padding then the
270 supplied data is used directly and not encapsulated. In the case of X9.31
271 padding for RSA the algorithm identifier byte is added or checked and removed
272 if this control is called. If it is not called then the first byte of the plaintext
273 buffer is expected to be the algorithm identifier byte.
275 The EVP_PKEY_CTX_get_rsa_padding() function gets the RSA padding mode for B<ctx>.
277 The EVP_PKEY_CTX_set_rsa_pss_saltlen() macro sets the RSA PSS salt length to
278 B<len>. As its name implies it is only supported for PSS padding. Three special
279 values are supported: B<RSA_PSS_SALTLEN_DIGEST> sets the salt length to the
280 digest length, B<RSA_PSS_SALTLEN_MAX> sets the salt length to the maximum
281 permissible value. When verifying B<RSA_PSS_SALTLEN_AUTO> causes the salt length
282 to be automatically determined based on the B<PSS> block structure. If this
283 macro is not called maximum salt length is used when signing and auto detection
284 when verifying is used by default.
286 The EVP_PKEY_CTX_get_rsa_pss_saltlen() macro gets the RSA PSS salt length
287 for B<ctx>. The padding mode must have been set to B<RSA_PKCS1_PSS_PADDING>.
289 The EVP_PKEY_CTX_set_rsa_keygen_bits() macro sets the RSA key length for
290 RSA key generation to B<bits>. If not specified 1024 bits is used.
292 The EVP_PKEY_CTX_set_rsa_keygen_pubexp() macro sets the public exponent value
293 for RSA key generation to B<pubexp>. Currently it should be an odd integer. The
294 B<pubexp> pointer is used internally by this function so it should not be
295 modified or freed after the call. If not specified 65537 is used.
297 The EVP_PKEY_CTX_set_rsa_keygen_primes() macro sets the number of primes for
298 RSA key generation to B<primes>. If not specified 2 is used.
300 The EVP_PKEY_CTX_set_rsa_mgf1_md_name() function sets the MGF1 digest for RSA
301 padding schemes to the digest named B<mdname>. If the RSA algorithm
302 implementation for the selected provider supports it then the digest will be
303 fetched using the properties B<mdprops>. If not explicitly set the signing
304 digest is used. The padding mode must have been set to B<RSA_PKCS1_OAEP_PADDING>
305 or B<RSA_PKCS1_PSS_PADDING>.
307 The EVP_PKEY_CTX_set_rsa_mgf1_md() function does the same as
308 EVP_PKEY_CTX_set_rsa_mgf1_md_name() except that the name of the digest is
309 inferred from the supplied B<md> and it is not possible to specify any
312 The EVP_PKEY_CTX_get_rsa_mgf1_md_name() function gets the name of the MGF1
313 digest algorithm for B<ctx>. If not explicitly set the signing digest is used.
314 The padding mode must have been set to B<RSA_PKCS1_OAEP_PADDING> or
315 B<RSA_PKCS1_PSS_PADDING>.
317 The EVP_PKEY_CTX_get_rsa_mgf1_md() function does the same as
318 EVP_PKEY_CTX_get_rsa_mgf1_md_name() except that it returns a pointer to an
319 EVP_MD object instead. Note that only known, built-in EVP_MD objects will be
320 returned. The EVP_MD object may be NULL if the digest is not one of these (such
321 as a digest only implemented in a third party provider).
323 The EVP_PKEY_CTX_set_rsa_oaep_md_name() function sets the message digest type
324 used in RSA OAEP to the digest named B<mdname>. If the RSA algorithm
325 implementation for the selected provider supports it then the digest will be
326 fetched using the properties B<mdprops>. The padding mode must have been set to
327 B<RSA_PKCS1_OAEP_PADDING>.
329 The EVP_PKEY_CTX_set_rsa_oaep_md() function does the same as
330 EVP_PKEY_CTX_set_rsa_oaep_md_name() except that the name of the digest is
331 inferred from the supplied B<md> and it is not possible to specify any
334 The EVP_PKEY_CTX_get_rsa_oaep_md_name() function gets the message digest
335 algorithm name used in RSA OAEP and stores it in the buffer B<name> which is of
336 size B<namelen>. The padding mode must have been set to
337 B<RSA_PKCS1_OAEP_PADDING>. The buffer should be sufficiently large for any
338 expected digest algorithm names or the function will fail.
340 The EVP_PKEY_CTX_get_rsa_oaep_md() function does the same as
341 EVP_PKEY_CTX_get_rsa_oaep_md_name() except that it returns a pointer to an
342 EVP_MD object instead. Note that only known, built-in EVP_MD objects will be
343 returned. The EVP_MD object may be NULL if the digest is not one of these (such
344 as a digest only implemented in a third party provider).
346 The EVP_PKEY_CTX_set0_rsa_oaep_label() function sets the RSA OAEP label to
347 B<label> and its length to B<len>. If B<label> is NULL or B<len> is 0,
348 the label is cleared. The library takes ownership of the label so the
349 caller should not free the original memory pointed to by B<label>.
350 The padding mode must have been set to B<RSA_PKCS1_OAEP_PADDING>.
352 The EVP_PKEY_CTX_get0_rsa_oaep_label() function gets the RSA OAEP label to
353 B<label>. The return value is the label length. The padding mode
354 must have been set to B<RSA_PKCS1_OAEP_PADDING>. The resulting pointer is owned
355 by the library and should not be freed by the caller.
357 B<RSA_PKCS1_WITH_TLS_PADDING> is used when decrypting an RSA encrypted TLS
358 pre-master secret in a TLS ClientKeyExchange message. It is the same as
359 RSA_PKCS1_PADDING except that it additionally verifies that the result is the
360 correct length and the first two bytes are the protocol version initially
361 requested by the client. If the encrypted content is publicly invalid then the
362 decryption will fail. However, if the padding checks fail then decryption will
363 still appear to succeed but a random TLS premaster secret will be returned
364 instead. This padding mode accepts two parameters which can be set using the
365 L<EVP_PKEY_CTX_set_params(3)> function. These are
366 OSSL_ASYM_CIPHER_PARAM_TLS_CLIENT_VERSION and
367 OSSL_ASYM_CIPHER_PARAM_TLS_NEGOTIATED_VERSION, both of which are expected to be
368 unsigned integers. Normally only the first of these will be set and represents
369 the TLS protocol version that was first requested by the client (e.g. 0x0303 for
370 TLSv1.2, 0x0302 for TLSv1.1 etc). Historically some buggy clients would use the
371 negotiated protocol version instead of the protocol version first requested. If
372 this behaviour should be tolerated then
373 OSSL_ASYM_CIPHER_PARAM_TLS_NEGOTIATED_VERSION should be set to the actual
374 negotiated protocol version. Otherwise it should be left unset.
376 =head2 DSA parameters
378 The EVP_PKEY_CTX_set_dsa_paramgen_bits() macro sets the number of bits used
379 for DSA parameter generation to B<nbits>. If not specified, 1024 is used.
381 The EVP_PKEY_CTX_set_dsa_paramgen_q_bits() macro sets the number of bits in the
382 subprime parameter B<q> for DSA parameter generation to B<qbits>. If not
383 specified, 160 is used. If a digest function is specified below, this parameter
384 is ignored and instead, the number of bits in B<q> matches the size of the
387 The EVP_PKEY_CTX_set_dsa_paramgen_md() macro sets the digest function used for
388 DSA parameter generation to B<md>. If not specified, one of SHA-1, SHA-224, or
389 SHA-256 is selected to match the bit length of B<q> above.
393 The EVP_PKEY_CTX_set_dh_paramgen_prime_len() macro sets the length of the DH
394 prime parameter B<p> for DH parameter generation. If this macro is not called
395 then 1024 is used. Only accepts lengths greater than or equal to 256.
397 The EVP_PKEY_CTX_set_dh_paramgen_subprime_len() macro sets the length of the DH
398 optional subprime parameter B<q> for DH parameter generation. The default is
399 256 if the prime is at least 2048 bits long or 160 otherwise. The DH
400 paramgen type must have been set to x9.42.
402 The EVP_PKEY_CTX_set_dh_paramgen_generator() macro sets DH generator to B<gen>
403 for DH parameter generation. If not specified 2 is used.
405 The EVP_PKEY_CTX_set_dh_paramgen_type() macro sets the key type for DH
406 parameter generation. Use 0 for PKCS#3 DH and 1 for X9.42 DH.
409 The EVP_PKEY_CTX_set_dh_pad() function sets the DH padding mode.
410 If B<pad> is 1 the shared secret is padded with zeros up to the size of the DH
412 If B<pad> is zero (the default) then no padding is performed.
414 EVP_PKEY_CTX_set_dh_nid() sets the DH parameters to values corresponding to
415 B<nid> as defined in RFC7919. The B<nid> parameter must be B<NID_ffdhe2048>,
416 B<NID_ffdhe3072>, B<NID_ffdhe4096>, B<NID_ffdhe6144>, B<NID_ffdhe8192>
417 or B<NID_undef> to clear the stored value. This macro can be called during
418 parameter or key generation.
419 The nid parameter and the rfc5114 parameter are mutually exclusive.
421 The EVP_PKEY_CTX_set_dh_rfc5114() and EVP_PKEY_CTX_set_dhx_rfc5114() macros are
422 synonymous. They set the DH parameters to the values defined in RFC5114. The
423 B<rfc5114> parameter must be 1, 2 or 3 corresponding to RFC5114 sections
424 2.1, 2.2 and 2.3. or 0 to clear the stored value. This macro can be called
425 during parameter generation. The B<ctx> must have a key type of
427 The rfc5114 parameter and the nid parameter are mutually exclusive.
429 =head2 DH key derivation function parameters
431 Note that all of the following functions require that the B<ctx> parameter has
432 a private key type of B<EVP_PKEY_DHX>. When using key derivation, the output of
433 EVP_PKEY_derive() is the output of the KDF instead of the DH shared secret.
434 The KDF output is typically used as a Key Encryption Key (KEK) that in turn
435 encrypts a Content Encryption Key (CEK).
437 The EVP_PKEY_CTX_set_dh_kdf_type() macro sets the key derivation function type
438 to B<kdf> for DH key derivation. Possible values are B<EVP_PKEY_DH_KDF_NONE>
439 and B<EVP_PKEY_DH_KDF_X9_42> which uses the key derivation specified in RFC2631
440 (based on the keying algorithm described in X9.42). When using key derivation,
441 the B<kdf_oid>, B<kdf_md> and B<kdf_outlen> parameters must also be specified.
443 The EVP_PKEY_CTX_get_dh_kdf_type() macro gets the key derivation function type
444 for B<ctx> used for DH key derivation. Possible values are B<EVP_PKEY_DH_KDF_NONE>
445 and B<EVP_PKEY_DH_KDF_X9_42>.
447 The EVP_PKEY_CTX_set0_dh_kdf_oid() macro sets the key derivation function
448 object identifier to B<oid> for DH key derivation. This OID should identify
449 the algorithm to be used with the Content Encryption Key.
450 The library takes ownership of the object identifier so the caller should not
451 free the original memory pointed to by B<oid>.
453 The EVP_PKEY_CTX_get0_dh_kdf_oid() macro gets the key derivation function oid
454 for B<ctx> used for DH key derivation. The resulting pointer is owned by the
455 library and should not be freed by the caller.
457 The EVP_PKEY_CTX_set_dh_kdf_md() macro sets the key derivation function
458 message digest to B<md> for DH key derivation. Note that RFC2631 specifies
459 that this digest should be SHA1 but OpenSSL tolerates other digests.
461 The EVP_PKEY_CTX_get_dh_kdf_md() macro gets the key derivation function
462 message digest for B<ctx> used for DH key derivation.
464 The EVP_PKEY_CTX_set_dh_kdf_outlen() macro sets the key derivation function
465 output length to B<len> for DH key derivation.
467 The EVP_PKEY_CTX_get_dh_kdf_outlen() macro gets the key derivation function
468 output length for B<ctx> used for DH key derivation.
470 The EVP_PKEY_CTX_set0_dh_kdf_ukm() macro sets the user key material to
471 B<ukm> and its length to B<len> for DH key derivation. This parameter is optional
472 and corresponds to the partyAInfo field in RFC2631 terms. The specification
473 requires that it is 512 bits long but this is not enforced by OpenSSL.
474 The library takes ownership of the user key material so the caller should not
475 free the original memory pointed to by B<ukm>.
477 The EVP_PKEY_CTX_get0_dh_kdf_ukm() macro gets the user key material for B<ctx>.
478 The return value is the user key material length. The resulting pointer is owned
479 by the library and should not be freed by the caller.
483 The EVP_PKEY_CTX_set_ec_paramgen_curve_nid() sets the EC curve for EC parameter
484 generation to B<nid>. For EC parameter generation this macro must be called
485 or an error occurs because there is no default curve.
486 This function can also be called to set the curve explicitly when
487 generating an EC key.
489 The EVP_PKEY_CTX_set_ec_param_enc() macro sets the EC parameter encoding to
490 B<param_enc> when generating EC parameters or an EC key. The encoding can be
491 B<OPENSSL_EC_EXPLICIT_CURVE> for explicit parameters (the default in versions
492 of OpenSSL before 1.1.0) or B<OPENSSL_EC_NAMED_CURVE> to use named curve form.
493 For maximum compatibility the named curve form should be used. Note: the
494 B<OPENSSL_EC_NAMED_CURVE> value was added in OpenSSL 1.1.0; previous
495 versions should use 0 instead.
497 =head2 ECDH parameters
499 The EVP_PKEY_CTX_set_ecdh_cofactor_mode() macro sets the cofactor mode to
500 B<cofactor_mode> for ECDH key derivation. Possible values are 1 to enable
501 cofactor key derivation, 0 to disable it and -1 to clear the stored cofactor
502 mode and fallback to the private key cofactor mode.
504 The EVP_PKEY_CTX_get_ecdh_cofactor_mode() macro returns the cofactor mode for
505 B<ctx> used for ECDH key derivation. Possible values are 1 when cofactor key
506 derivation is enabled and 0 otherwise.
508 =head2 ECDH key derivation function parameters
510 The EVP_PKEY_CTX_set_ecdh_kdf_type() macro sets the key derivation function type
511 to B<kdf> for ECDH key derivation. Possible values are B<EVP_PKEY_ECDH_KDF_NONE>
512 and B<EVP_PKEY_ECDH_KDF_X9_63> which uses the key derivation specified in X9.63.
513 When using key derivation, the B<kdf_md> and B<kdf_outlen> parameters must
516 The EVP_PKEY_CTX_get_ecdh_kdf_type() macro returns the key derivation function
517 type for B<ctx> used for ECDH key derivation. Possible values are
518 B<EVP_PKEY_ECDH_KDF_NONE> and B<EVP_PKEY_ECDH_KDF_X9_63>.
520 The EVP_PKEY_CTX_set_ecdh_kdf_md() macro sets the key derivation function
521 message digest to B<md> for ECDH key derivation. Note that X9.63 specifies
522 that this digest should be SHA1 but OpenSSL tolerates other digests.
524 The EVP_PKEY_CTX_get_ecdh_kdf_md() macro gets the key derivation function
525 message digest for B<ctx> used for ECDH key derivation.
527 The EVP_PKEY_CTX_set_ecdh_kdf_outlen() macro sets the key derivation function
528 output length to B<len> for ECDH key derivation.
530 The EVP_PKEY_CTX_get_ecdh_kdf_outlen() macro gets the key derivation function
531 output length for B<ctx> used for ECDH key derivation.
533 The EVP_PKEY_CTX_set0_ecdh_kdf_ukm() macro sets the user key material to B<ukm>
534 for ECDH key derivation. This parameter is optional and corresponds to the
535 shared info in X9.63 terms. The library takes ownership of the user key material
536 so the caller should not free the original memory pointed to by B<ukm>.
538 The EVP_PKEY_CTX_get0_ecdh_kdf_ukm() macro gets the user key material for B<ctx>.
539 The return value is the user key material length. The resulting pointer is owned
540 by the library and should not be freed by the caller.
542 =head2 Other parameters
544 The EVP_PKEY_CTX_set1_id(), EVP_PKEY_CTX_get1_id() and EVP_PKEY_CTX_get1_id_len()
545 macros are used to manipulate the special identifier field for specific signature
546 algorithms such as SM2. The EVP_PKEY_CTX_set1_id() sets an ID pointed by B<id> with
547 the length B<id_len> to the library. The library takes a copy of the id so that
548 the caller can safely free the original memory pointed to by B<id>. The
549 EVP_PKEY_CTX_get1_id_len() macro returns the length of the ID set via a previous
550 call to EVP_PKEY_CTX_set1_id(). The length is usually used to allocate adequate
551 memory for further calls to EVP_PKEY_CTX_get1_id(). The EVP_PKEY_CTX_get1_id()
552 macro returns the previously set ID value to caller in B<id>. The caller should
553 allocate adequate memory space for the B<id> before calling EVP_PKEY_CTX_get1_id().
557 EVP_PKEY_CTX_set_params() returns 1 for success or 0 otherwise.
558 EVP_PKEY_CTX_settable_params() returns an OSSL_PARAM array on success or NULL on
560 It may also return NULL if there are no settable parameters available.
562 All other functions and macros described on this page return a positive value
563 for success and 0 or a negative value for failure. In particular a return value
564 of -2 indicates the operation is not supported by the public key algorithm.
568 L<EVP_PKEY_CTX_new(3)>,
569 L<EVP_PKEY_encrypt(3)>,
570 L<EVP_PKEY_decrypt(3)>,
572 L<EVP_PKEY_verify(3)>,
573 L<EVP_PKEY_verify_recover(3)>,
574 L<EVP_PKEY_derive(3)>,
575 L<EVP_PKEY_keygen(3)>
579 EVP_PKEY_CTX_get_signature_md(), EVP_PKEY_CTX_set_signature_md(),
580 EVP_PKEY_CTX_set_dh_pad(), EVP_PKEY_CTX_set_rsa_padding(),
581 EVP_PKEY_CTX_get_rsa_padding(), EVP_PKEY_CTX_get_rsa_mgf1_md(),
582 EVP_PKEY_CTX_set_rsa_mgf1_md(), EVP_PKEY_CTX_set_rsa_oaep_md(),
583 EVP_PKEY_CTX_get_rsa_oaep_md(), EVP_PKEY_CTX_set0_rsa_oaep_label(),
584 EVP_PKEY_CTX_get0_rsa_oaep_label() were macros in OpenSSL 1.1.1 and below. From
585 OpenSSL 3.0 they are functions.
587 EVP_PKEY_CTX_get_rsa_oaep_md_name(), EVP_PKEY_CTX_get_rsa_mgf1_md_name(),
588 EVP_PKEY_CTX_set_rsa_mgf1_md_name() and EVP_PKEY_CTX_set_rsa_oaep_md_name() were
589 added in OpenSSL 3.0.
591 The EVP_PKEY_CTX_set1_id(), EVP_PKEY_CTX_get1_id() and
592 EVP_PKEY_CTX_get1_id_len() macros were added in 1.1.1, other functions were
593 added in OpenSSL 1.0.0.
597 Copyright 2006-2018 The OpenSSL Project Authors. All Rights Reserved.
599 Licensed under the Apache License 2.0 (the "License"). You may not use
600 this file except in compliance with the License. You can obtain a copy
601 in the file LICENSE in the source distribution or at
602 L<https://www.openssl.org/source/license.html>.