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.
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 B<cmd> = B<EVP_PKEY_CTRL_SET_MAC_KEY>, B<p1> is the length of the MAC key,
215 and B<p2> is 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() macro sets the RSA PSS salt length to
276 B<len>. As its name implies it is only supported for PSS padding. Three special
277 values are supported: B<RSA_PSS_SALTLEN_DIGEST> sets the salt length to the
278 digest length, B<RSA_PSS_SALTLEN_MAX> sets the salt length to the maximum
279 permissible value. When verifying B<RSA_PSS_SALTLEN_AUTO> causes the salt length
280 to be automatically determined based on the B<PSS> block structure. If this
281 macro is not called maximum salt length is used when signing and auto detection
282 when verifying is used by default.
284 The EVP_PKEY_CTX_get_rsa_pss_saltlen() macro gets the RSA PSS salt length
285 for B<ctx>. The padding mode must have been set to B<RSA_PKCS1_PSS_PADDING>.
287 The EVP_PKEY_CTX_set_rsa_keygen_bits() macro sets the RSA key length for
288 RSA key generation to B<bits>. If not specified 1024 bits is used.
290 The EVP_PKEY_CTX_set_rsa_keygen_pubexp() macro sets the public exponent value
291 for RSA key generation to B<pubexp>. Currently it should be an odd integer. The
292 B<pubexp> pointer is used internally by this function so it should not be
293 modified or freed after the call. If not specified 65537 is used.
295 The EVP_PKEY_CTX_set_rsa_keygen_primes() macro sets the number of primes for
296 RSA key generation to B<primes>. If not specified 2 is used.
298 The EVP_PKEY_CTX_set_rsa_mgf1_md_name() function sets the MGF1 digest for RSA
299 padding schemes to the digest named B<mdname>. If the RSA algorithm
300 implementation for the selected provider supports it then the digest will be
301 fetched using the properties B<mdprops>. If not explicitly set the signing
302 digest is used. The padding mode must have been set to B<RSA_PKCS1_OAEP_PADDING>
303 or B<RSA_PKCS1_PSS_PADDING>.
305 The EVP_PKEY_CTX_set_rsa_mgf1_md() function does the same as
306 EVP_PKEY_CTX_set_rsa_mgf1_md_name() except that the name of the digest is
307 inferred from the supplied B<md> and it is not possible to specify any
310 The EVP_PKEY_CTX_get_rsa_mgf1_md_name() function gets the name of the MGF1
311 digest algorithm for B<ctx>. If not explicitly set the signing digest is used.
312 The padding mode must have been set to B<RSA_PKCS1_OAEP_PADDING> or
313 B<RSA_PKCS1_PSS_PADDING>.
315 The EVP_PKEY_CTX_get_rsa_mgf1_md() function does the same as
316 EVP_PKEY_CTX_get_rsa_mgf1_md_name() except that it returns a pointer to an
317 EVP_MD object instead. Note that only known, built-in EVP_MD objects will be
318 returned. The EVP_MD object may be NULL if the digest is not one of these (such
319 as a digest only implemented in a third party provider).
321 The EVP_PKEY_CTX_set_rsa_oaep_md_name() function sets the message digest type
322 used in RSA OAEP to the digest named B<mdname>. If the RSA algorithm
323 implementation for the selected provider supports it then the digest will be
324 fetched using the properties B<mdprops>. The padding mode must have been set to
325 B<RSA_PKCS1_OAEP_PADDING>.
327 The EVP_PKEY_CTX_set_rsa_oaep_md() function does the same as
328 EVP_PKEY_CTX_set_rsa_oaep_md_name() except that the name of the digest is
329 inferred from the supplied B<md> and it is not possible to specify any
332 The EVP_PKEY_CTX_get_rsa_oaep_md_name() function gets the message digest
333 algorithm name used in RSA OAEP and stores it in the buffer B<name> which is of
334 size B<namelen>. The padding mode must have been set to
335 B<RSA_PKCS1_OAEP_PADDING>. The buffer should be sufficiently large for any
336 expected digest algorithm names or the function will fail.
338 The EVP_PKEY_CTX_get_rsa_oaep_md() function does the same as
339 EVP_PKEY_CTX_get_rsa_oaep_md_name() except that it returns a pointer to an
340 EVP_MD object instead. Note that only known, built-in EVP_MD objects will be
341 returned. The EVP_MD object may be NULL if the digest is not one of these (such
342 as a digest only implemented in a third party provider).
344 The EVP_PKEY_CTX_set0_rsa_oaep_label() function sets the RSA OAEP label to
345 B<label> and its length to B<len>. If B<label> is NULL or B<len> is 0,
346 the label is cleared. The library takes ownership of the label so the
347 caller should not free the original memory pointed to by B<label>.
348 The padding mode must have been set to B<RSA_PKCS1_OAEP_PADDING>.
350 The EVP_PKEY_CTX_get0_rsa_oaep_label() function gets the RSA OAEP label to
351 B<label>. The return value is the label length. The padding mode
352 must have been set to B<RSA_PKCS1_OAEP_PADDING>. The resulting pointer is owned
353 by the library and should not be freed by the caller.
355 B<RSA_PKCS1_WITH_TLS_PADDING> is used when decrypting an RSA encrypted TLS
356 pre-master secret in a TLS ClientKeyExchange message. It is the same as
357 RSA_PKCS1_PADDING except that it additionally verifies that the result is the
358 correct length and the first two bytes are the protocol version initially
359 requested by the client. If the encrypted content is publicly invalid then the
360 decryption will fail. However, if the padding checks fail then decryption will
361 still appear to succeed but a random TLS premaster secret will be returned
362 instead. This padding mode accepts two parameters which can be set using the
363 L<EVP_PKEY_CTX_set_params(3)> function. These are
364 OSSL_ASYM_CIPHER_PARAM_TLS_CLIENT_VERSION and
365 OSSL_ASYM_CIPHER_PARAM_TLS_NEGOTIATED_VERSION, both of which are expected to be
366 unsigned integers. Normally only the first of these will be set and represents
367 the TLS protocol version that was first requested by the client (e.g. 0x0303 for
368 TLSv1.2, 0x0302 for TLSv1.1 etc). Historically some buggy clients would use the
369 negotiated protocol version instead of the protocol version first requested. If
370 this behaviour should be tolerated then
371 OSSL_ASYM_CIPHER_PARAM_TLS_NEGOTIATED_VERSION should be set to the actual
372 negotiated protocol version. Otherwise it should be left unset.
374 =head2 DSA parameters
376 The EVP_PKEY_CTX_set_dsa_paramgen_bits() macro sets the number of bits used
377 for DSA parameter generation to B<nbits>. If not specified, 1024 is used.
379 The EVP_PKEY_CTX_set_dsa_paramgen_q_bits() macro sets the number of bits in the
380 subprime parameter B<q> for DSA parameter generation to B<qbits>. If not
381 specified, 160 is used. If a digest function is specified below, this parameter
382 is ignored and instead, the number of bits in B<q> matches the size of the
385 The EVP_PKEY_CTX_set_dsa_paramgen_md() macro sets the digest function used for
386 DSA parameter generation to B<md>. If not specified, one of SHA-1, SHA-224, or
387 SHA-256 is selected to match the bit length of B<q> above.
391 The EVP_PKEY_CTX_set_dh_paramgen_prime_len() macro sets the length of the DH
392 prime parameter B<p> for DH parameter generation. If this macro is not called
393 then 1024 is used. Only accepts lengths greater than or equal to 256.
395 The EVP_PKEY_CTX_set_dh_paramgen_subprime_len() macro sets the length of the DH
396 optional subprime parameter B<q> for DH parameter generation. The default is
397 256 if the prime is at least 2048 bits long or 160 otherwise. The DH
398 paramgen type must have been set to x9.42.
400 The EVP_PKEY_CTX_set_dh_paramgen_generator() macro sets DH generator to B<gen>
401 for DH parameter generation. If not specified 2 is used.
403 The EVP_PKEY_CTX_set_dh_paramgen_type() macro sets the key type for DH
404 parameter generation. Use 0 for PKCS#3 DH and 1 for X9.42 DH.
407 The EVP_PKEY_CTX_set_dh_pad() function sets the DH padding mode.
408 If B<pad> is 1 the shared secret is padded with zeros up to the size of the DH
410 If B<pad> is zero (the default) then no padding is performed.
412 EVP_PKEY_CTX_set_dh_nid() sets the DH parameters to values corresponding to
413 B<nid> as defined in RFC7919 or RFC3526. The B<nid> parameter must be
414 B<NID_ffdhe2048>, B<NID_ffdhe3072>, B<NID_ffdhe4096>, B<NID_ffdhe6144>,
415 B<NID_ffdhe8192>, B<NID_modp_1536>, B<NID_modp_2048>, B<NID_modp_3072>,
416 B<NID_modp_4096>, B<NID_modp_6144>, B<NID_modp_8192> or B<NID_undef> to clear
417 the stored value. This macro can be called during parameter or key generation.
418 The nid parameter and the rfc5114 parameter are mutually exclusive.
420 The EVP_PKEY_CTX_set_dh_rfc5114() and EVP_PKEY_CTX_set_dhx_rfc5114() macros are
421 synonymous. They set the DH parameters to the values defined in RFC5114. The
422 B<rfc5114> parameter must be 1, 2 or 3 corresponding to RFC5114 sections
423 2.1, 2.2 and 2.3. or 0 to clear the stored value. This macro can be called
424 during parameter generation. The B<ctx> must have a key type of
426 The rfc5114 parameter and the nid parameter are mutually exclusive.
428 =head2 DH key derivation function parameters
430 Note that all of the following functions require that the B<ctx> parameter has
431 a private key type of B<EVP_PKEY_DHX>. When using key derivation, the output of
432 EVP_PKEY_derive() is the output of the KDF instead of the DH shared secret.
433 The KDF output is typically used as a Key Encryption Key (KEK) that in turn
434 encrypts a Content Encryption Key (CEK).
436 The EVP_PKEY_CTX_set_dh_kdf_type() macro sets the key derivation function type
437 to B<kdf> for DH key derivation. Possible values are B<EVP_PKEY_DH_KDF_NONE>
438 and B<EVP_PKEY_DH_KDF_X9_42> which uses the key derivation specified in RFC2631
439 (based on the keying algorithm described in X9.42). When using key derivation,
440 the B<kdf_oid>, B<kdf_md> and B<kdf_outlen> parameters must also be specified.
442 The EVP_PKEY_CTX_get_dh_kdf_type() macro gets the key derivation function type
443 for B<ctx> used for DH key derivation. Possible values are B<EVP_PKEY_DH_KDF_NONE>
444 and B<EVP_PKEY_DH_KDF_X9_42>.
446 The EVP_PKEY_CTX_set0_dh_kdf_oid() macro sets the key derivation function
447 object identifier to B<oid> for DH key derivation. This OID should identify
448 the algorithm to be used with the Content Encryption Key.
449 The library takes ownership of the object identifier so the caller should not
450 free the original memory pointed to by B<oid>.
452 The EVP_PKEY_CTX_get0_dh_kdf_oid() macro gets the key derivation function oid
453 for B<ctx> used for DH key derivation. The resulting pointer is owned by the
454 library and should not be freed by the caller.
456 The EVP_PKEY_CTX_set_dh_kdf_md() macro sets the key derivation function
457 message digest to B<md> for DH key derivation. Note that RFC2631 specifies
458 that this digest should be SHA1 but OpenSSL tolerates other digests.
460 The EVP_PKEY_CTX_get_dh_kdf_md() macro gets the key derivation function
461 message digest for B<ctx> used for DH key derivation.
463 The EVP_PKEY_CTX_set_dh_kdf_outlen() macro sets the key derivation function
464 output length to B<len> for DH key derivation.
466 The EVP_PKEY_CTX_get_dh_kdf_outlen() macro gets the key derivation function
467 output length for B<ctx> used for DH key derivation.
469 The EVP_PKEY_CTX_set0_dh_kdf_ukm() macro sets the user key material to
470 B<ukm> and its length to B<len> for DH key derivation. This parameter is optional
471 and corresponds to the partyAInfo field in RFC2631 terms. The specification
472 requires that it is 512 bits long but this is not enforced by OpenSSL.
473 The library takes ownership of the user key material so the caller should not
474 free the original memory pointed to by B<ukm>.
476 The EVP_PKEY_CTX_get0_dh_kdf_ukm() macro gets the user key material for B<ctx>.
477 The return value is the user key material length. The resulting pointer is owned
478 by the library and should not be freed by the caller.
482 The EVP_PKEY_CTX_set_ec_paramgen_curve_nid() sets the EC curve for EC parameter
483 generation to B<nid>. For EC parameter generation this macro must be called
484 or an error occurs because there is no default curve.
485 This function can also be called to set the curve explicitly when
486 generating an EC key.
488 The EVP_PKEY_CTX_set_ec_param_enc() macro sets the EC parameter encoding to
489 B<param_enc> when generating EC parameters or an EC key. The encoding can be
490 B<OPENSSL_EC_EXPLICIT_CURVE> for explicit parameters (the default in versions
491 of OpenSSL before 1.1.0) or B<OPENSSL_EC_NAMED_CURVE> to use named curve form.
492 For maximum compatibility the named curve form should be used. Note: the
493 B<OPENSSL_EC_NAMED_CURVE> value was added in OpenSSL 1.1.0; previous
494 versions should use 0 instead.
496 =head2 ECDH parameters
498 The EVP_PKEY_CTX_set_ecdh_cofactor_mode() macro sets the cofactor mode to
499 B<cofactor_mode> for ECDH key derivation. Possible values are 1 to enable
500 cofactor key derivation, 0 to disable it and -1 to clear the stored cofactor
501 mode and fallback to the private key cofactor mode.
503 The EVP_PKEY_CTX_get_ecdh_cofactor_mode() macro returns the cofactor mode for
504 B<ctx> used for ECDH key derivation. Possible values are 1 when cofactor key
505 derivation is enabled and 0 otherwise.
507 =head2 ECDH key derivation function parameters
509 The EVP_PKEY_CTX_set_ecdh_kdf_type() macro sets the key derivation function type
510 to B<kdf> for ECDH key derivation. Possible values are B<EVP_PKEY_ECDH_KDF_NONE>
511 and B<EVP_PKEY_ECDH_KDF_X9_63> which uses the key derivation specified in X9.63.
512 When using key derivation, the B<kdf_md> and B<kdf_outlen> parameters must
515 The EVP_PKEY_CTX_get_ecdh_kdf_type() macro returns the key derivation function
516 type for B<ctx> used for ECDH key derivation. Possible values are
517 B<EVP_PKEY_ECDH_KDF_NONE> and B<EVP_PKEY_ECDH_KDF_X9_63>.
519 The EVP_PKEY_CTX_set_ecdh_kdf_md() macro sets the key derivation function
520 message digest to B<md> for ECDH key derivation. Note that X9.63 specifies
521 that this digest should be SHA1 but OpenSSL tolerates other digests.
523 The EVP_PKEY_CTX_get_ecdh_kdf_md() macro gets the key derivation function
524 message digest for B<ctx> used for ECDH key derivation.
526 The EVP_PKEY_CTX_set_ecdh_kdf_outlen() macro sets the key derivation function
527 output length to B<len> for ECDH key derivation.
529 The EVP_PKEY_CTX_get_ecdh_kdf_outlen() macro gets the key derivation function
530 output length for B<ctx> used for ECDH key derivation.
532 The EVP_PKEY_CTX_set0_ecdh_kdf_ukm() macro sets the user key material to B<ukm>
533 for ECDH key derivation. This parameter is optional and corresponds to the
534 shared info in X9.63 terms. The library takes ownership of the user key material
535 so the caller should not free the original memory pointed to by B<ukm>.
537 The EVP_PKEY_CTX_get0_ecdh_kdf_ukm() macro gets the user key material for B<ctx>.
538 The return value is the user key material length. The resulting pointer is owned
539 by the library and should not be freed by the caller.
541 =head2 Other parameters
543 The EVP_PKEY_CTX_set1_id(), EVP_PKEY_CTX_get1_id() and EVP_PKEY_CTX_get1_id_len()
544 macros are used to manipulate the special identifier field for specific signature
545 algorithms such as SM2. The EVP_PKEY_CTX_set1_id() sets an ID pointed by B<id> with
546 the length B<id_len> to the library. The library takes a copy of the id so that
547 the caller can safely free the original memory pointed to by B<id>. The
548 EVP_PKEY_CTX_get1_id_len() macro returns the length of the ID set via a previous
549 call to EVP_PKEY_CTX_set1_id(). The length is usually used to allocate adequate
550 memory for further calls to EVP_PKEY_CTX_get1_id(). The EVP_PKEY_CTX_get1_id()
551 macro returns the previously set ID value to caller in B<id>. The caller should
552 allocate adequate memory space for the B<id> before calling EVP_PKEY_CTX_get1_id().
556 EVP_PKEY_CTX_set_params() returns 1 for success or 0 otherwise.
557 EVP_PKEY_CTX_settable_params() returns an OSSL_PARAM array on success or NULL on
559 It may also return NULL if there are no settable parameters available.
561 All other functions and macros described on this page return a positive value
562 for success and 0 or a negative value for failure. In particular a return value
563 of -2 indicates the operation is not supported by the public key algorithm.
567 L<EVP_PKEY_CTX_new(3)>,
568 L<EVP_PKEY_encrypt(3)>,
569 L<EVP_PKEY_decrypt(3)>,
571 L<EVP_PKEY_verify(3)>,
572 L<EVP_PKEY_verify_recover(3)>,
573 L<EVP_PKEY_derive(3)>,
574 L<EVP_PKEY_keygen(3)>
578 EVP_PKEY_CTX_get_signature_md(), EVP_PKEY_CTX_set_signature_md(),
579 EVP_PKEY_CTX_set_dh_pad(), EVP_PKEY_CTX_set_rsa_padding(),
580 EVP_PKEY_CTX_get_rsa_padding(), EVP_PKEY_CTX_get_rsa_mgf1_md(),
581 EVP_PKEY_CTX_set_rsa_mgf1_md(), EVP_PKEY_CTX_set_rsa_oaep_md(),
582 EVP_PKEY_CTX_get_rsa_oaep_md(), EVP_PKEY_CTX_set0_rsa_oaep_label(),
583 EVP_PKEY_CTX_get0_rsa_oaep_label() were macros in OpenSSL 1.1.1 and below. From
584 OpenSSL 3.0 they are functions.
586 EVP_PKEY_CTX_get_rsa_oaep_md_name(), EVP_PKEY_CTX_get_rsa_mgf1_md_name(),
587 EVP_PKEY_CTX_set_rsa_mgf1_md_name() and EVP_PKEY_CTX_set_rsa_oaep_md_name() were
588 added in OpenSSL 3.0.
590 The EVP_PKEY_CTX_set1_id(), EVP_PKEY_CTX_get1_id() and
591 EVP_PKEY_CTX_get1_id_len() macros were added in 1.1.1, other functions were
592 added in OpenSSL 1.0.0.
596 Copyright 2006-2018 The OpenSSL Project Authors. All Rights Reserved.
598 Licensed under the Apache License 2.0 (the "License"). You may not use
599 this file except in compliance with the License. You can obtain a copy
600 in the file LICENSE in the source distribution or at
601 L<https://www.openssl.org/source/license.html>.