7 EVP_PKEY_CTX_ctrl_uint64,
9 EVP_PKEY_CTX_set_signature_md,
10 EVP_PKEY_CTX_get_signature_md,
11 EVP_PKEY_CTX_set_mac_key,
12 EVP_PKEY_CTX_set_group_name,
13 EVP_PKEY_CTX_get_group_name,
14 EVP_PKEY_CTX_set_rsa_padding,
15 EVP_PKEY_CTX_get_rsa_padding,
16 EVP_PKEY_CTX_set_rsa_pss_saltlen,
17 EVP_PKEY_CTX_get_rsa_pss_saltlen,
18 EVP_PKEY_CTX_set_rsa_keygen_bits,
19 EVP_PKEY_CTX_set_rsa_keygen_pubexp,
20 EVP_PKEY_CTX_set_rsa_keygen_primes,
21 EVP_PKEY_CTX_set_rsa_mgf1_md_name,
22 EVP_PKEY_CTX_set_rsa_mgf1_md,
23 EVP_PKEY_CTX_get_rsa_mgf1_md,
24 EVP_PKEY_CTX_get_rsa_mgf1_md_name,
25 EVP_PKEY_CTX_set_rsa_oaep_md_name,
26 EVP_PKEY_CTX_set_rsa_oaep_md,
27 EVP_PKEY_CTX_get_rsa_oaep_md,
28 EVP_PKEY_CTX_get_rsa_oaep_md_name,
29 EVP_PKEY_CTX_set0_rsa_oaep_label,
30 EVP_PKEY_CTX_get0_rsa_oaep_label,
31 EVP_PKEY_CTX_set_dsa_paramgen_bits,
32 EVP_PKEY_CTX_set_dsa_paramgen_q_bits,
33 EVP_PKEY_CTX_set_dsa_paramgen_md,
34 EVP_PKEY_CTX_set_dsa_paramgen_md_props,
35 EVP_PKEY_CTX_set_dsa_paramgen_gindex,
36 EVP_PKEY_CTX_set_dsa_paramgen_type,
37 EVP_PKEY_CTX_set_dsa_paramgen_seed,
38 EVP_PKEY_CTX_set_dh_paramgen_prime_len,
39 EVP_PKEY_CTX_set_dh_paramgen_subprime_len,
40 EVP_PKEY_CTX_set_dh_paramgen_generator,
41 EVP_PKEY_CTX_set_dh_paramgen_type,
42 EVP_PKEY_CTX_set_dh_paramgen_gindex,
43 EVP_PKEY_CTX_set_dh_paramgen_seed,
44 EVP_PKEY_CTX_set_dh_rfc5114,
45 EVP_PKEY_CTX_set_dhx_rfc5114,
46 EVP_PKEY_CTX_set_dh_pad,
47 EVP_PKEY_CTX_set_dh_nid,
48 EVP_PKEY_CTX_set_dh_kdf_type,
49 EVP_PKEY_CTX_get_dh_kdf_type,
50 EVP_PKEY_CTX_set0_dh_kdf_oid,
51 EVP_PKEY_CTX_get0_dh_kdf_oid,
52 EVP_PKEY_CTX_set_dh_kdf_md,
53 EVP_PKEY_CTX_get_dh_kdf_md,
54 EVP_PKEY_CTX_set_dh_kdf_outlen,
55 EVP_PKEY_CTX_get_dh_kdf_outlen,
56 EVP_PKEY_CTX_set0_dh_kdf_ukm,
57 EVP_PKEY_CTX_get0_dh_kdf_ukm,
58 EVP_PKEY_CTX_set_ec_paramgen_curve_nid,
59 EVP_PKEY_CTX_set_ec_param_enc,
60 EVP_PKEY_CTX_set_ecdh_cofactor_mode,
61 EVP_PKEY_CTX_get_ecdh_cofactor_mode,
62 EVP_PKEY_CTX_set_ecdh_kdf_type,
63 EVP_PKEY_CTX_get_ecdh_kdf_type,
64 EVP_PKEY_CTX_set_ecdh_kdf_md,
65 EVP_PKEY_CTX_get_ecdh_kdf_md,
66 EVP_PKEY_CTX_set_ecdh_kdf_outlen,
67 EVP_PKEY_CTX_get_ecdh_kdf_outlen,
68 EVP_PKEY_CTX_set0_ecdh_kdf_ukm,
69 EVP_PKEY_CTX_get0_ecdh_kdf_ukm,
70 EVP_PKEY_CTX_set1_id, EVP_PKEY_CTX_get1_id, EVP_PKEY_CTX_get1_id_len
71 - algorithm specific control operations
75 #include <openssl/evp.h>
77 int EVP_PKEY_CTX_ctrl(EVP_PKEY_CTX *ctx, int keytype, int optype,
78 int cmd, int p1, void *p2);
79 int EVP_PKEY_CTX_ctrl_uint64(EVP_PKEY_CTX *ctx, int keytype, int optype,
80 int cmd, uint64_t value);
81 int EVP_PKEY_CTX_ctrl_str(EVP_PKEY_CTX *ctx, const char *type,
84 int EVP_PKEY_CTX_md(EVP_PKEY_CTX *ctx, int optype, int cmd, const char *md);
86 int EVP_PKEY_CTX_set_signature_md(EVP_PKEY_CTX *ctx, const EVP_MD *md);
87 int EVP_PKEY_CTX_get_signature_md(EVP_PKEY_CTX *ctx, const EVP_MD **pmd);
89 int EVP_PKEY_CTX_set_mac_key(EVP_PKEY_CTX *ctx, const unsigned char *key,
91 int EVP_PKEY_CTX_set_group_name(EVP_PKEY_CTX *ctx, const char *name);
92 int EVP_PKEY_CTX_get_group_name(EVP_PKEY_CTX *ctx, char *name, size_t namelen);
94 #include <openssl/rsa.h>
96 int EVP_PKEY_CTX_set_rsa_padding(EVP_PKEY_CTX *ctx, int pad);
97 int EVP_PKEY_CTX_get_rsa_padding(EVP_PKEY_CTX *ctx, int *pad);
98 int EVP_PKEY_CTX_set_rsa_pss_saltlen(EVP_PKEY_CTX *ctx, int saltlen);
99 int EVP_PKEY_CTX_get_rsa_pss_saltlen(EVP_PKEY_CTX *ctx, int *saltlen);
100 int EVP_PKEY_CTX_set_rsa_keygen_bits(EVP_PKEY_CTX *ctx, int mbits);
101 int EVP_PKEY_CTX_set_rsa_keygen_pubexp(EVP_PKEY_CTX *ctx, BIGNUM *pubexp);
102 int EVP_PKEY_CTX_set_rsa_keygen_primes(EVP_PKEY_CTX *ctx, int primes);
103 int EVP_PKEY_CTX_set_rsa_mgf1_md_name(EVP_PKEY_CTX *ctx, const char *mdname,
104 const char *mdprops);
105 int EVP_PKEY_CTX_set_rsa_mgf1_md(EVP_PKEY_CTX *ctx, const EVP_MD *md);
106 int EVP_PKEY_CTX_get_rsa_mgf1_md(EVP_PKEY_CTX *ctx, const EVP_MD **md);
107 int EVP_PKEY_CTX_get_rsa_mgf1_md_name(EVP_PKEY_CTX *ctx, char *name,
109 int EVP_PKEY_CTX_set_rsa_oaep_md_name(EVP_PKEY_CTX *ctx, const char *mdname,
110 const char *mdprops);
111 int EVP_PKEY_CTX_set_rsa_oaep_md(EVP_PKEY_CTX *ctx, const EVP_MD *md);
112 int EVP_PKEY_CTX_get_rsa_oaep_md(EVP_PKEY_CTX *ctx, const EVP_MD **md);
113 int EVP_PKEY_CTX_get_rsa_oaep_md_name(EVP_PKEY_CTX *ctx, char *name,
115 int EVP_PKEY_CTX_set0_rsa_oaep_label(EVP_PKEY_CTX *ctx, unsigned char *label, int len);
116 int EVP_PKEY_CTX_get0_rsa_oaep_label(EVP_PKEY_CTX *ctx, unsigned char **label);
118 #include <openssl/dsa.h>
120 int EVP_PKEY_CTX_set_dsa_paramgen_bits(EVP_PKEY_CTX *ctx, int nbits);
121 int EVP_PKEY_CTX_set_dsa_paramgen_q_bits(EVP_PKEY_CTX *ctx, int qbits);
122 int EVP_PKEY_CTX_set_dsa_paramgen_md(EVP_PKEY_CTX *ctx, const EVP_MD *md);
123 int EVP_PKEY_CTX_set_dsa_paramgen_md_props(EVP_PKEY_CTX *ctx,
125 const char *md_properties);
126 int EVP_PKEY_CTX_set_dsa_paramgen_type(EVP_PKEY_CTX *ctx, const char *name);
127 int EVP_PKEY_CTX_set_dsa_paramgen_gindex(EVP_PKEY_CTX *ctx, int gindex);
128 int EVP_PKEY_CTX_set_dsa_paramgen_seed(EVP_PKEY_CTX *ctx,
129 const unsigned char *seed,
132 #include <openssl/dh.h>
134 int EVP_PKEY_CTX_set_dh_paramgen_prime_len(EVP_PKEY_CTX *ctx, int len);
135 int EVP_PKEY_CTX_set_dh_paramgen_subprime_len(EVP_PKEY_CTX *ctx, int len);
136 int EVP_PKEY_CTX_set_dh_paramgen_generator(EVP_PKEY_CTX *ctx, int gen);
137 int EVP_PKEY_CTX_set_dh_paramgen_type(EVP_PKEY_CTX *ctx, int type);
138 int EVP_PKEY_CTX_set_dh_pad(EVP_PKEY_CTX *ctx, int pad);
139 int EVP_PKEY_CTX_set_dh_nid(EVP_PKEY_CTX *ctx, int nid);
140 int EVP_PKEY_CTX_set_dh_rfc5114(EVP_PKEY_CTX *ctx, int rfc5114);
141 int EVP_PKEY_CTX_set_dhx_rfc5114(EVP_PKEY_CTX *ctx, int rfc5114);
142 int EVP_PKEY_CTX_set_dh_paramgen_gindex(EVP_PKEY_CTX *ctx, int gindex);
143 int EVP_PKEY_CTX_set_dh_paramgen_seed(EVP_PKEY_CTX *ctx,
144 const unsigned char *seed,
146 int EVP_PKEY_CTX_set_dh_kdf_type(EVP_PKEY_CTX *ctx, int kdf);
147 int EVP_PKEY_CTX_get_dh_kdf_type(EVP_PKEY_CTX *ctx);
148 int EVP_PKEY_CTX_set0_dh_kdf_oid(EVP_PKEY_CTX *ctx, ASN1_OBJECT *oid);
149 int EVP_PKEY_CTX_get0_dh_kdf_oid(EVP_PKEY_CTX *ctx, ASN1_OBJECT **oid);
150 int EVP_PKEY_CTX_set_dh_kdf_md(EVP_PKEY_CTX *ctx, const EVP_MD *md);
151 int EVP_PKEY_CTX_get_dh_kdf_md(EVP_PKEY_CTX *ctx, const EVP_MD **md);
152 int EVP_PKEY_CTX_set_dh_kdf_outlen(EVP_PKEY_CTX *ctx, int len);
153 int EVP_PKEY_CTX_get_dh_kdf_outlen(EVP_PKEY_CTX *ctx, int *len);
154 int EVP_PKEY_CTX_set0_dh_kdf_ukm(EVP_PKEY_CTX *ctx, unsigned char *ukm, int len);
155 int EVP_PKEY_CTX_get0_dh_kdf_ukm(EVP_PKEY_CTX *ctx, unsigned char **ukm);
157 #include <openssl/ec.h>
159 int EVP_PKEY_CTX_set_ec_paramgen_curve_nid(EVP_PKEY_CTX *ctx, int nid);
160 int EVP_PKEY_CTX_set_ec_param_enc(EVP_PKEY_CTX *ctx, int param_enc);
161 int EVP_PKEY_CTX_set_ecdh_cofactor_mode(EVP_PKEY_CTX *ctx, int cofactor_mode);
162 int EVP_PKEY_CTX_get_ecdh_cofactor_mode(EVP_PKEY_CTX *ctx);
163 int EVP_PKEY_CTX_set_ecdh_kdf_type(EVP_PKEY_CTX *ctx, int kdf);
164 int EVP_PKEY_CTX_get_ecdh_kdf_type(EVP_PKEY_CTX *ctx);
165 int EVP_PKEY_CTX_set_ecdh_kdf_md(EVP_PKEY_CTX *ctx, const EVP_MD *md);
166 int EVP_PKEY_CTX_get_ecdh_kdf_md(EVP_PKEY_CTX *ctx, const EVP_MD **md);
167 int EVP_PKEY_CTX_set_ecdh_kdf_outlen(EVP_PKEY_CTX *ctx, int len);
168 int EVP_PKEY_CTX_get_ecdh_kdf_outlen(EVP_PKEY_CTX *ctx, int *len);
169 int EVP_PKEY_CTX_set0_ecdh_kdf_ukm(EVP_PKEY_CTX *ctx, unsigned char *ukm, int len);
170 int EVP_PKEY_CTX_get0_ecdh_kdf_ukm(EVP_PKEY_CTX *ctx, unsigned char **ukm);
172 int EVP_PKEY_CTX_set1_id(EVP_PKEY_CTX *ctx, void *id, size_t id_len);
173 int EVP_PKEY_CTX_get1_id(EVP_PKEY_CTX *ctx, void *id);
174 int EVP_PKEY_CTX_get1_id_len(EVP_PKEY_CTX *ctx, size_t *id_len);
178 The function EVP_PKEY_CTX_ctrl() sends a control operation to the context
179 I<ctx>. The key type used must match I<keytype> if it is not -1. The parameter
180 I<optype> is a mask indicating which operations the control can be applied to.
181 The control command is indicated in I<cmd> and any additional arguments in
184 For I<cmd> = B<EVP_PKEY_CTRL_SET_MAC_KEY>, I<p1> is the length of the MAC key,
185 and I<p2> is the MAC key. This is used by Poly1305, SipHash, HMAC and CMAC.
187 Applications will not normally call EVP_PKEY_CTX_ctrl() directly but will
188 instead call one of the algorithm specific macros below.
190 The function EVP_PKEY_CTX_ctrl_uint64() is a wrapper that directly passes a
191 uint64 value as I<p2> to EVP_PKEY_CTX_ctrl().
193 The function EVP_PKEY_CTX_ctrl_str() allows an application to send an algorithm
194 specific control operation to a context I<ctx> in string form. This is
195 intended to be used for options specified on the command line or in text
196 files. The commands supported are documented in the openssl utility
197 command line pages for the option I<-pkeyopt> which is supported by the
198 I<pkeyutl>, I<genpkey> and I<req> commands.
200 The function EVP_PKEY_CTX_md() sends a message digest control operation
201 to the context I<ctx>. The message digest is specified by its name I<md>.
203 The EVP_PKEY_CTX_set_signature_md() function sets the message digest type used
204 in a signature. It can be used in the RSA, DSA and ECDSA algorithms.
206 The EVP_PKEY_CTX_get_signature_md() function gets the message digest type used
207 in a signature. It can be used in the RSA, DSA and ECDSA algorithms.
209 All the remaining "functions" are implemented as macros.
211 Key generation typically involves setting up parameters to be used and
212 generating the private and public key data. Some algorithm implementations
213 allow private key data to be set explicitly using the EVP_PKEY_CTX_set_mac_key()
214 macro. In this case key generation is simply the process of setting up the
215 parameters for the key and then setting the raw key data to the value explicitly
216 provided by that macro. Normally applications would call
217 L<EVP_PKEY_new_raw_private_key(3)> or similar functions instead of this macro.
219 The EVP_PKEY_CTX_set_mac_key() macro can be used with any of the algorithms
220 supported by the L<EVP_PKEY_new_raw_private_key(3)> function.
222 EVP_PKEY_CTX_set_group_name() sets the group name to I<name> for parameter and
223 key generation. For example for EC keys this will set the curve name and for
224 DH keys it will set the name of the finite field group.
226 EVP_PKEY_CTX_get_group_name() finds the group name that's currently
227 set with I<ctx>, and writes it to the location that I<name> points at, as long
228 as its size I<namelen> is large enough to store that name, including a
229 terminating NUL byte.
231 =head2 RSA parameters
233 The EVP_PKEY_CTX_set_rsa_padding() function sets the RSA padding mode for I<ctx>.
234 The I<pad> parameter can take the value B<RSA_PKCS1_PADDING> for PKCS#1
235 padding, B<RSA_SSLV23_PADDING> for SSLv23 padding, B<RSA_NO_PADDING> for
236 no padding, B<RSA_PKCS1_OAEP_PADDING> for OAEP padding (encrypt and
237 decrypt only), B<RSA_X931_PADDING> for X9.31 padding (signature operations
238 only), B<RSA_PKCS1_PSS_PADDING> (sign and verify only) and
239 B<RSA_PKCS1_WITH_TLS_PADDING> for TLS RSA ClientKeyExchange message padding
242 Two RSA padding modes behave differently if EVP_PKEY_CTX_set_signature_md()
243 is used. If this macro is called for PKCS#1 padding the plaintext buffer is
244 an actual digest value and is encapsulated in a DigestInfo structure according
245 to PKCS#1 when signing and this structure is expected (and stripped off) when
246 verifying. If this control is not used with RSA and PKCS#1 padding then the
247 supplied data is used directly and not encapsulated. In the case of X9.31
248 padding for RSA the algorithm identifier byte is added or checked and removed
249 if this control is called. If it is not called then the first byte of the plaintext
250 buffer is expected to be the algorithm identifier byte.
252 The EVP_PKEY_CTX_get_rsa_padding() function gets the RSA padding mode for I<ctx>.
254 The EVP_PKEY_CTX_set_rsa_pss_saltlen() function sets the RSA PSS salt
255 length to I<saltlen>. As its name implies it is only supported for PSS
256 padding. If this function is not called then the maximum salt length
257 is used when signing and auto detection when verifying. Three special
258 values are supported:
262 =item B<RSA_PSS_SALTLEN_DIGEST>
264 sets the salt length to the digest length.
266 =item B<RSA_PSS_SALTLEN_MAX>
268 sets the salt length to the maximum permissible value.
270 =item B<RSA_PSS_SALTLEN_AUTO>
272 causes the salt length to be automatically determined based on the
273 B<PSS> block structure when verifying. When signing, it has the same
274 meaning as B<RSA_PSS_SALTLEN_MAX>.
278 The EVP_PKEY_CTX_get_rsa_pss_saltlen() function gets the RSA PSS salt length
279 for I<ctx>. The padding mode must already have been set to
280 B<RSA_PKCS1_PSS_PADDING>.
282 The EVP_PKEY_CTX_set_rsa_keygen_bits() macro sets the RSA key length for
283 RSA key generation to I<bits>. If not specified 2048 bits is used.
285 The EVP_PKEY_CTX_set_rsa_keygen_pubexp() macro sets the public exponent value
286 for RSA key generation to I<pubexp>. Currently it should be an odd integer. The
287 I<pubexp> pointer is used internally by this function so it should not be
288 modified or freed after the call. If not specified 65537 is used.
290 The EVP_PKEY_CTX_set_rsa_keygen_primes() macro sets the number of primes for
291 RSA key generation to I<primes>. If not specified 2 is used.
293 The EVP_PKEY_CTX_set_rsa_mgf1_md_name() function sets the MGF1 digest for RSA
294 padding schemes to the digest named I<mdname>. If the RSA algorithm
295 implementation for the selected provider supports it then the digest will be
296 fetched using the properties I<mdprops>. If not explicitly set the signing
297 digest is used. The padding mode must have been set to B<RSA_PKCS1_OAEP_PADDING>
298 or B<RSA_PKCS1_PSS_PADDING>.
300 The EVP_PKEY_CTX_set_rsa_mgf1_md() function does the same as
301 EVP_PKEY_CTX_set_rsa_mgf1_md_name() except that the name of the digest is
302 inferred from the supplied I<md> and it is not possible to specify any
305 The EVP_PKEY_CTX_get_rsa_mgf1_md_name() function gets the name of the MGF1
306 digest algorithm for I<ctx>. If not explicitly set the signing digest is used.
307 The padding mode must have been set to B<RSA_PKCS1_OAEP_PADDING> or
308 B<RSA_PKCS1_PSS_PADDING>.
310 The EVP_PKEY_CTX_get_rsa_mgf1_md() function does the same as
311 EVP_PKEY_CTX_get_rsa_mgf1_md_name() except that it returns a pointer to an
312 EVP_MD object instead. Note that only known, built-in EVP_MD objects will be
313 returned. The EVP_MD object may be NULL if the digest is not one of these (such
314 as a digest only implemented in a third party provider).
316 The EVP_PKEY_CTX_set_rsa_oaep_md_name() function sets the message digest type
317 used in RSA OAEP to the digest named I<mdname>. If the RSA algorithm
318 implementation for the selected provider supports it then the digest will be
319 fetched using the properties I<mdprops>. The padding mode must have been set to
320 B<RSA_PKCS1_OAEP_PADDING>.
322 The EVP_PKEY_CTX_set_rsa_oaep_md() function does the same as
323 EVP_PKEY_CTX_set_rsa_oaep_md_name() except that the name of the digest is
324 inferred from the supplied I<md> and it is not possible to specify any
327 The EVP_PKEY_CTX_get_rsa_oaep_md_name() function gets the message digest
328 algorithm name used in RSA OAEP and stores it in the buffer I<name> which is of
329 size I<namelen>. The padding mode must have been set to
330 B<RSA_PKCS1_OAEP_PADDING>. The buffer should be sufficiently large for any
331 expected digest algorithm names or the function will fail.
333 The EVP_PKEY_CTX_get_rsa_oaep_md() function does the same as
334 EVP_PKEY_CTX_get_rsa_oaep_md_name() except that it returns a pointer to an
335 EVP_MD object instead. Note that only known, built-in EVP_MD objects will be
336 returned. The EVP_MD object may be NULL if the digest is not one of these (such
337 as a digest only implemented in a third party provider).
339 The EVP_PKEY_CTX_set0_rsa_oaep_label() function sets the RSA OAEP label to
340 I<label> and its length to I<len>. If I<label> is NULL or I<len> is 0,
341 the label is cleared. The library takes ownership of the label so the
342 caller should not free the original memory pointed to by I<label>.
343 The padding mode must have been set to B<RSA_PKCS1_OAEP_PADDING>.
345 The EVP_PKEY_CTX_get0_rsa_oaep_label() function gets the RSA OAEP label to
346 I<label>. The return value is the label length. The padding mode
347 must have been set to B<RSA_PKCS1_OAEP_PADDING>. The resulting pointer is owned
348 by the library and should not be freed by the caller.
350 B<RSA_PKCS1_WITH_TLS_PADDING> is used when decrypting an RSA encrypted TLS
351 pre-master secret in a TLS ClientKeyExchange message. It is the same as
352 RSA_PKCS1_PADDING except that it additionally verifies that the result is the
353 correct length and the first two bytes are the protocol version initially
354 requested by the client. If the encrypted content is publicly invalid then the
355 decryption will fail. However, if the padding checks fail then decryption will
356 still appear to succeed but a random TLS premaster secret will be returned
357 instead. This padding mode accepts two parameters which can be set using the
358 L<EVP_PKEY_CTX_set_params(3)> function. These are
359 OSSL_ASYM_CIPHER_PARAM_TLS_CLIENT_VERSION and
360 OSSL_ASYM_CIPHER_PARAM_TLS_NEGOTIATED_VERSION, both of which are expected to be
361 unsigned integers. Normally only the first of these will be set and represents
362 the TLS protocol version that was first requested by the client (e.g. 0x0303 for
363 TLSv1.2, 0x0302 for TLSv1.1 etc). Historically some buggy clients would use the
364 negotiated protocol version instead of the protocol version first requested. If
365 this behaviour should be tolerated then
366 OSSL_ASYM_CIPHER_PARAM_TLS_NEGOTIATED_VERSION should be set to the actual
367 negotiated protocol version. Otherwise it should be left unset.
369 =head2 DSA parameters
371 The EVP_PKEY_CTX_set_dsa_paramgen_bits() method sets the number of bits used
372 for DSA parameter generation to I<nbits>. If not specified, 2048 is used.
374 The EVP_PKEY_CTX_set_dsa_paramgen_q_bits() method sets the number of bits in the
375 subprime parameter I<q> for DSA parameter generation to I<qbits>. If not
376 specified, 224 is used. If a digest function is specified below, this parameter
377 is ignored and instead, the number of bits in I<q> matches the size of the
380 The EVP_PKEY_CTX_set_dsa_paramgen_md() method sets the digest function used for
381 DSA parameter generation to I<md>. If not specified, one of SHA-1, SHA-224, or
382 SHA-256 is selected to match the bit length of I<q> above.
384 The EVP_PKEY_CTX_set_dsa_paramgen_md_props() method sets the digest function
385 used for DSA parameter generation using I<md_name> and I<md_properties> to
386 retrieve the digest from a provider.
387 If not specified, I<md_name> will be set to one of SHA-1, SHA-224, or
388 SHA-256 depending on the bit length of I<q> above. I<md_properties> is a
389 property query string that has a default value of '' if not specified.
391 The EVP_PKEY_CTX_set_dsa_paramgen_gindex() method sets the I<gindex> used by
392 the generator G. The default value is -1 which uses unverifiable g, otherwise
393 a positive value uses verifiable g. This value must be saved if key validation
394 of g is required, since it is not part of a persisted key.
396 The EVP_PKEY_CTX_set_dsa_paramgen_seed() method sets the I<seed> to use for
397 generation rather than using a randomly generated value for the seed. This is
398 useful for testing purposes only and can fail if the seed does not produce
399 primes for both p & q on its first iteration. This value must be saved if
400 key validation of p, q, and verifiable g are required, since it is not part of
403 The EVP_PKEY_CTX_set_dsa_paramgen_type() method sets the generation type to
404 use FIPS186-4 generation if I<name> is "fips186_4", or FIPS186-2 generation if
405 I<name> is "fips186_2". The default value is "fips186_4".
409 The EVP_PKEY_CTX_set_dh_paramgen_prime_len() macro sets the length of the DH
410 prime parameter I<p> for DH parameter generation. If this macro is not called
411 then 2048 is used. Only accepts lengths greater than or equal to 256.
413 The EVP_PKEY_CTX_set_dh_paramgen_subprime_len() macro sets the length of the DH
414 optional subprime parameter I<q> for DH parameter generation. The default is
415 256 if the prime is at least 2048 bits long or 160 otherwise. The DH
416 paramgen type must have been set to "fips186_4".
418 The EVP_PKEY_CTX_set_dh_paramgen_generator() macro sets DH generator to I<gen>
419 for DH parameter generation. If not specified 2 is used.
421 The EVP_PKEY_CTX_set_dh_paramgen_type() macro sets the key type for DH
422 parameter generation. The supported parameters are:
426 =item B<DH_PARAMGEN_TYPE_GROUP>
428 Use a named group. If only the safe prime parameter I<p> is set this can be
429 used to select a ffdhe safe prime group of the correct size.
431 =item B<DH_PARAMGEN_TYPE_FIPS_186_4>
433 FIPS186-4 FFC parameter generator.
435 =item B<DH_PARAMGEN_TYPE_FIPS_186_2>
437 FIPS186-2 FFC parameter generator (X9.42 DH).
439 =item B<DH_PARAMGEN_TYPE_GENERATOR>
441 Uses a safe prime generator g (PKCS#3 format).
445 The default is B<DH_PARAMGEN_TYPE_GENERATOR>.
447 The EVP_PKEY_CTX_set_dh_paramgen_gindex() method sets the I<gindex> used by
448 the generator G. The default value is -1 which uses unverifiable g, otherwise
449 a positive value uses verifiable g. This value must be saved if key validation
450 of g is required, since it is not part of a persisted key.
452 The EVP_PKEY_CTX_set_dh_paramgen_seed() method sets the I<seed> to use for
453 generation rather than using a randomly generated value for the seed. This is
454 useful for testing purposes only and can fail if the seed does not produce
455 primes for both p & q on its first iteration. This value must be saved if
456 key validation of p, q, and verifiable g are required, since it is not part of
459 The EVP_PKEY_CTX_set_dh_pad() function sets the DH padding mode.
460 If I<pad> is 1 the shared secret is padded with zeros up to the size of the DH
462 If I<pad> is zero (the default) then no padding is performed.
464 EVP_PKEY_CTX_set_dh_nid() sets the DH parameters to values corresponding to
465 I<nid> as defined in RFC7919 or RFC3526. The I<nid> parameter must be
466 B<NID_ffdhe2048>, B<NID_ffdhe3072>, B<NID_ffdhe4096>, B<NID_ffdhe6144>,
467 B<NID_ffdhe8192>, B<NID_modp_1536>, B<NID_modp_2048>, B<NID_modp_3072>,
468 B<NID_modp_4096>, B<NID_modp_6144>, B<NID_modp_8192> or B<NID_undef> to clear
469 the stored value. This macro can be called during parameter or key generation.
470 The nid parameter and the rfc5114 parameter are mutually exclusive.
472 The EVP_PKEY_CTX_set_dh_rfc5114() and EVP_PKEY_CTX_set_dhx_rfc5114() macros are
473 synonymous. They set the DH parameters to the values defined in RFC5114. The
474 I<rfc5114> parameter must be 1, 2 or 3 corresponding to RFC5114 sections
475 2.1, 2.2 and 2.3. or 0 to clear the stored value. This macro can be called
476 during parameter generation. The I<ctx> must have a key type of
478 The rfc5114 parameter and the nid parameter are mutually exclusive.
480 =head2 DH key derivation function parameters
482 Note that all of the following functions require that the I<ctx> parameter has
483 a private key type of B<EVP_PKEY_DHX>. When using key derivation, the output of
484 EVP_PKEY_derive() is the output of the KDF instead of the DH shared secret.
485 The KDF output is typically used as a Key Encryption Key (KEK) that in turn
486 encrypts a Content Encryption Key (CEK).
488 The EVP_PKEY_CTX_set_dh_kdf_type() macro sets the key derivation function type
489 to I<kdf> for DH key derivation. Possible values are B<EVP_PKEY_DH_KDF_NONE>
490 and B<EVP_PKEY_DH_KDF_X9_42> which uses the key derivation specified in RFC2631
491 (based on the keying algorithm described in X9.42). When using key derivation,
492 the I<kdf_oid>, I<kdf_md> and I<kdf_outlen> parameters must also be specified.
494 The EVP_PKEY_CTX_get_dh_kdf_type() macro gets the key derivation function type
495 for I<ctx> used for DH key derivation. Possible values are B<EVP_PKEY_DH_KDF_NONE>
496 and B<EVP_PKEY_DH_KDF_X9_42>.
498 The EVP_PKEY_CTX_set0_dh_kdf_oid() macro sets the key derivation function
499 object identifier to I<oid> for DH key derivation. This OID should identify
500 the algorithm to be used with the Content Encryption Key.
501 The library takes ownership of the object identifier so the caller should not
502 free the original memory pointed to by I<oid>.
504 The EVP_PKEY_CTX_get0_dh_kdf_oid() macro gets the key derivation function oid
505 for I<ctx> used for DH key derivation. The resulting pointer is owned by the
506 library and should not be freed by the caller.
508 The EVP_PKEY_CTX_set_dh_kdf_md() macro sets the key derivation function
509 message digest to I<md> for DH key derivation. Note that RFC2631 specifies
510 that this digest should be SHA1 but OpenSSL tolerates other digests.
512 The EVP_PKEY_CTX_get_dh_kdf_md() macro gets the key derivation function
513 message digest for I<ctx> used for DH key derivation.
515 The EVP_PKEY_CTX_set_dh_kdf_outlen() macro sets the key derivation function
516 output length to I<len> for DH key derivation.
518 The EVP_PKEY_CTX_get_dh_kdf_outlen() macro gets the key derivation function
519 output length for I<ctx> used for DH key derivation.
521 The EVP_PKEY_CTX_set0_dh_kdf_ukm() macro sets the user key material to
522 I<ukm> and its length to I<len> for DH key derivation. This parameter is optional
523 and corresponds to the partyAInfo field in RFC2631 terms. The specification
524 requires that it is 512 bits long but this is not enforced by OpenSSL.
525 The library takes ownership of the user key material so the caller should not
526 free the original memory pointed to by I<ukm>.
528 The EVP_PKEY_CTX_get0_dh_kdf_ukm() macro gets the user key material for I<ctx>.
529 The return value is the user key material length. The resulting pointer is owned
530 by the library and should not be freed by the caller.
534 Use EVP_PKEY_CTX_set_group_name() (described above) to set the curve name to
535 I<name> for parameter and key generation.
537 EVP_PKEY_CTX_set_ec_paramgen_curve_nid() does the same as
538 EVP_PKEY_CTX_set_group_name(), but is specific to EC and uses a I<nid> rather
541 For EC parameter generation, one of EVP_PKEY_CTX_set_group_name()
542 or EVP_PKEY_CTX_set_ec_paramgen_curve_nid() must be called or an error occurs
543 because there is no default curve.
544 These function can also be called to set the curve explicitly when
545 generating an EC key.
547 EVP_PKEY_CTX_get_group_name() (described above) can be used to obtain the curve
548 name that's currently set with I<ctx>.
550 The EVP_PKEY_CTX_set_ec_param_enc() macro sets the EC parameter encoding to
551 I<param_enc> when generating EC parameters or an EC key. The encoding can be
552 B<OPENSSL_EC_EXPLICIT_CURVE> for explicit parameters (the default in versions
553 of OpenSSL before 1.1.0) or B<OPENSSL_EC_NAMED_CURVE> to use named curve form.
554 For maximum compatibility the named curve form should be used. Note: the
555 B<OPENSSL_EC_NAMED_CURVE> value was added in OpenSSL 1.1.0; previous
556 versions should use 0 instead.
558 =head2 ECDH parameters
560 The EVP_PKEY_CTX_set_ecdh_cofactor_mode() macro sets the cofactor mode to
561 I<cofactor_mode> for ECDH key derivation. Possible values are 1 to enable
562 cofactor key derivation, 0 to disable it and -1 to clear the stored cofactor
563 mode and fallback to the private key cofactor mode.
565 The EVP_PKEY_CTX_get_ecdh_cofactor_mode() macro returns the cofactor mode for
566 I<ctx> used for ECDH key derivation. Possible values are 1 when cofactor key
567 derivation is enabled and 0 otherwise.
569 =head2 ECDH key derivation function parameters
571 The EVP_PKEY_CTX_set_ecdh_kdf_type() macro sets the key derivation function type
572 to I<kdf> for ECDH key derivation. Possible values are B<EVP_PKEY_ECDH_KDF_NONE>
573 and B<EVP_PKEY_ECDH_KDF_X9_63> which uses the key derivation specified in X9.63.
574 When using key derivation, the I<kdf_md> and I<kdf_outlen> parameters must
577 The EVP_PKEY_CTX_get_ecdh_kdf_type() macro returns the key derivation function
578 type for I<ctx> used for ECDH key derivation. Possible values are
579 B<EVP_PKEY_ECDH_KDF_NONE> and B<EVP_PKEY_ECDH_KDF_X9_63>.
581 The EVP_PKEY_CTX_set_ecdh_kdf_md() macro sets the key derivation function
582 message digest to I<md> for ECDH key derivation. Note that X9.63 specifies
583 that this digest should be SHA1 but OpenSSL tolerates other digests.
585 The EVP_PKEY_CTX_get_ecdh_kdf_md() macro gets the key derivation function
586 message digest for I<ctx> used for ECDH key derivation.
588 The EVP_PKEY_CTX_set_ecdh_kdf_outlen() macro sets the key derivation function
589 output length to I<len> for ECDH key derivation.
591 The EVP_PKEY_CTX_get_ecdh_kdf_outlen() macro gets the key derivation function
592 output length for I<ctx> used for ECDH key derivation.
594 The EVP_PKEY_CTX_set0_ecdh_kdf_ukm() macro sets the user key material to I<ukm>
595 for ECDH key derivation. This parameter is optional and corresponds to the
596 shared info in X9.63 terms. The library takes ownership of the user key material
597 so the caller should not free the original memory pointed to by I<ukm>.
599 The EVP_PKEY_CTX_get0_ecdh_kdf_ukm() macro gets the user key material for I<ctx>.
600 The return value is the user key material length. The resulting pointer is owned
601 by the library and should not be freed by the caller.
603 =head2 Other parameters
605 The EVP_PKEY_CTX_set1_id(), EVP_PKEY_CTX_get1_id() and EVP_PKEY_CTX_get1_id_len()
606 macros are used to manipulate the special identifier field for specific signature
607 algorithms such as SM2. The EVP_PKEY_CTX_set1_id() sets an ID pointed by I<id> with
608 the length I<id_len> to the library. The library takes a copy of the id so that
609 the caller can safely free the original memory pointed to by I<id>. The
610 EVP_PKEY_CTX_get1_id_len() macro returns the length of the ID set via a previous
611 call to EVP_PKEY_CTX_set1_id(). The length is usually used to allocate adequate
612 memory for further calls to EVP_PKEY_CTX_get1_id(). The EVP_PKEY_CTX_get1_id()
613 macro returns the previously set ID value to caller in I<id>. The caller should
614 allocate adequate memory space for the I<id> before calling EVP_PKEY_CTX_get1_id().
618 All other functions and macros described on this page return a positive value
619 for success and 0 or a negative value for failure. In particular a return value
620 of -2 indicates the operation is not supported by the public key algorithm.
624 L<EVP_PKEY_CTX_set_params(3)>,
625 L<EVP_PKEY_CTX_new(3)>,
626 L<EVP_PKEY_encrypt(3)>,
627 L<EVP_PKEY_decrypt(3)>,
629 L<EVP_PKEY_verify(3)>,
630 L<EVP_PKEY_verify_recover(3)>,
631 L<EVP_PKEY_derive(3)>,
632 L<EVP_PKEY_keygen(3)>
636 EVP_PKEY_CTX_get_signature_md(), EVP_PKEY_CTX_set_signature_md(),
637 EVP_PKEY_CTX_set_dh_pad(), EVP_PKEY_CTX_set_rsa_padding(),
638 EVP_PKEY_CTX_get_rsa_padding(), EVP_PKEY_CTX_get_rsa_mgf1_md(),
639 EVP_PKEY_CTX_set_rsa_mgf1_md(), EVP_PKEY_CTX_set_rsa_oaep_md(),
640 EVP_PKEY_CTX_get_rsa_oaep_md(), EVP_PKEY_CTX_set0_rsa_oaep_label(),
641 EVP_PKEY_CTX_get0_rsa_oaep_label(), EVP_PKEY_CTX_set_rsa_pss_saltlen(),
642 EVP_PKEY_CTX_get_rsa_pss_saltlen(), EVP_PKEY_CTX_set_dsa_paramgen_bits(),
643 EVP_PKEY_CTX_set_dsa_paramgen_q_bits() and EVP_PKEY_CTX_set_dsa_paramgen_md()
644 were macros in OpenSSL 1.1.1 and below.
645 From OpenSSL 3.0 they are functions.
647 EVP_PKEY_CTX_get_rsa_oaep_md_name(), EVP_PKEY_CTX_get_rsa_mgf1_md_name(),
648 EVP_PKEY_CTX_set_rsa_mgf1_md_name(), EVP_PKEY_CTX_set_rsa_oaep_md_name(),
649 EVP_PKEY_CTX_set_dsa_paramgen_md_props(), EVP_PKEY_CTX_set_dsa_paramgen_gindex(),
650 EVP_PKEY_CTX_set_dsa_paramgen_type(), EVP_PKEY_CTX_set_dsa_paramgen_seed(),
651 EVP_PKEY_CTX_set_group_name() and EVP_PKEY_CTX_get_group_name()
652 were added in OpenSSL 3.0.
654 The EVP_PKEY_CTX_set1_id(), EVP_PKEY_CTX_get1_id() and
655 EVP_PKEY_CTX_get1_id_len() macros were added in 1.1.1, other functions were
656 added in OpenSSL 1.0.0.
660 Copyright 2006-2020 The OpenSSL Project Authors. All Rights Reserved.
662 Licensed under the Apache License 2.0 (the "License"). You may not use
663 this file except in compliance with the License. You can obtain a copy
664 in the file LICENSE in the source distribution or at
665 L<https://www.openssl.org/source/license.html>.