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_dsa_paramgen_md_props,
37 EVP_PKEY_CTX_set_dsa_paramgen_gindex,
38 EVP_PKEY_CTX_set_dsa_paramgen_type,
39 EVP_PKEY_CTX_set_dsa_paramgen_seed,
40 EVP_PKEY_CTX_set_dh_paramgen_prime_len,
41 EVP_PKEY_CTX_set_dh_paramgen_subprime_len,
42 EVP_PKEY_CTX_set_dh_paramgen_generator,
43 EVP_PKEY_CTX_set_dh_paramgen_type,
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_name,
59 EVP_PKEY_CTX_get_ec_paramgen_curve_name,
60 EVP_PKEY_CTX_set_ec_paramgen_curve_nid,
61 EVP_PKEY_CTX_set_ec_param_enc,
62 EVP_PKEY_CTX_set_ecdh_cofactor_mode,
63 EVP_PKEY_CTX_get_ecdh_cofactor_mode,
64 EVP_PKEY_CTX_set_ecdh_kdf_type,
65 EVP_PKEY_CTX_get_ecdh_kdf_type,
66 EVP_PKEY_CTX_set_ecdh_kdf_md,
67 EVP_PKEY_CTX_get_ecdh_kdf_md,
68 EVP_PKEY_CTX_set_ecdh_kdf_outlen,
69 EVP_PKEY_CTX_get_ecdh_kdf_outlen,
70 EVP_PKEY_CTX_set0_ecdh_kdf_ukm,
71 EVP_PKEY_CTX_get0_ecdh_kdf_ukm,
72 EVP_PKEY_CTX_set1_id, EVP_PKEY_CTX_get1_id, EVP_PKEY_CTX_get1_id_len
73 - algorithm specific control operations
77 #include <openssl/evp.h>
79 int EVP_PKEY_CTX_get_params(EVP_PKEY_CTX *ctx, OSSL_PARAM *params);
80 const OSSL_PARAM *EVP_PKEY_CTX_gettable_params(EVP_PKEY_CTX *ctx);
81 int EVP_PKEY_CTX_set_params(EVP_PKEY_CTX *ctx, OSSL_PARAM *params);
82 const OSSL_PARAM *EVP_PKEY_CTX_settable_params(EVP_PKEY_CTX *ctx);
84 int EVP_PKEY_CTX_ctrl(EVP_PKEY_CTX *ctx, int keytype, int optype,
85 int cmd, int p1, void *p2);
86 int EVP_PKEY_CTX_ctrl_uint64(EVP_PKEY_CTX *ctx, int keytype, int optype,
87 int cmd, uint64_t value);
88 int EVP_PKEY_CTX_ctrl_str(EVP_PKEY_CTX *ctx, const char *type,
91 int EVP_PKEY_CTX_md(EVP_PKEY_CTX *ctx, int optype, int cmd, const char *md);
93 int EVP_PKEY_CTX_set_signature_md(EVP_PKEY_CTX *ctx, const EVP_MD *md);
94 int EVP_PKEY_CTX_get_signature_md(EVP_PKEY_CTX *ctx, const EVP_MD **pmd);
96 int EVP_PKEY_CTX_set_mac_key(EVP_PKEY_CTX *ctx, const unsigned char *key,
99 #include <openssl/rsa.h>
101 int EVP_PKEY_CTX_set_rsa_padding(EVP_PKEY_CTX *ctx, int pad);
102 int EVP_PKEY_CTX_get_rsa_padding(EVP_PKEY_CTX *ctx, int *pad);
103 int EVP_PKEY_CTX_set_rsa_pss_saltlen(EVP_PKEY_CTX *ctx, int saltlen);
104 int EVP_PKEY_CTX_get_rsa_pss_saltlen(EVP_PKEY_CTX *ctx, int *saltlen);
105 int EVP_PKEY_CTX_set_rsa_keygen_bits(EVP_PKEY_CTX *ctx, int mbits);
106 int EVP_PKEY_CTX_set_rsa_keygen_pubexp(EVP_PKEY_CTX *ctx, BIGNUM *pubexp);
107 int EVP_PKEY_CTX_set_rsa_keygen_primes(EVP_PKEY_CTX *ctx, int primes);
108 int EVP_PKEY_CTX_set_rsa_mgf1_md_name(EVP_PKEY_CTX *ctx, const char *mdname,
109 const char *mdprops);
110 int EVP_PKEY_CTX_set_rsa_mgf1_md(EVP_PKEY_CTX *ctx, const EVP_MD *md);
111 int EVP_PKEY_CTX_get_rsa_mgf1_md(EVP_PKEY_CTX *ctx, const EVP_MD **md);
112 int EVP_PKEY_CTX_get_rsa_mgf1_md_name(EVP_PKEY_CTX *ctx, char *name,
114 int EVP_PKEY_CTX_set_rsa_oaep_md_name(EVP_PKEY_CTX *ctx, const char *mdname,
115 const char *mdprops);
116 int EVP_PKEY_CTX_set_rsa_oaep_md(EVP_PKEY_CTX *ctx, const EVP_MD *md);
117 int EVP_PKEY_CTX_get_rsa_oaep_md(EVP_PKEY_CTX *ctx, const EVP_MD **md);
118 int EVP_PKEY_CTX_get_rsa_oaep_md_name(EVP_PKEY_CTX *ctx, char *name,
120 int EVP_PKEY_CTX_set0_rsa_oaep_label(EVP_PKEY_CTX *ctx, unsigned char *label, int len);
121 int EVP_PKEY_CTX_get0_rsa_oaep_label(EVP_PKEY_CTX *ctx, unsigned char **label);
123 #include <openssl/dsa.h>
125 int EVP_PKEY_CTX_set_dsa_paramgen_bits(EVP_PKEY_CTX *ctx, int nbits);
126 int EVP_PKEY_CTX_set_dsa_paramgen_q_bits(EVP_PKEY_CTX *ctx, int qbits);
127 int EVP_PKEY_CTX_set_dsa_paramgen_md(EVP_PKEY_CTX *ctx, const EVP_MD *md);
128 int EVP_PKEY_CTX_set_dsa_paramgen_md_props(EVP_PKEY_CTX *ctx,
130 const char *md_properties);
131 int EVP_PKEY_CTX_set_dsa_paramgen_type(EVP_PKEY_CTX *ctx, const char *name);
132 int EVP_PKEY_CTX_set_dsa_paramgen_gindex(EVP_PKEY_CTX *ctx, int gindex);
133 int EVP_PKEY_CTX_set_dsa_paramgen_seed(EVP_PKEY_CTX *ctx,
134 const unsigned char *seed,
137 #include <openssl/dh.h>
139 int EVP_PKEY_CTX_set_dh_paramgen_prime_len(EVP_PKEY_CTX *ctx, int len);
140 int EVP_PKEY_CTX_set_dh_paramgen_subprime_len(EVP_PKEY_CTX *ctx, int len);
141 int EVP_PKEY_CTX_set_dh_paramgen_generator(EVP_PKEY_CTX *ctx, int gen);
142 int EVP_PKEY_CTX_set_dh_paramgen_type(EVP_PKEY_CTX *ctx, int type);
143 int EVP_PKEY_CTX_set_dh_pad(EVP_PKEY_CTX *ctx, int pad);
144 int EVP_PKEY_CTX_set_dh_nid(EVP_PKEY_CTX *ctx, int nid);
145 int EVP_PKEY_CTX_set_dh_rfc5114(EVP_PKEY_CTX *ctx, int rfc5114);
146 int EVP_PKEY_CTX_set_dhx_rfc5114(EVP_PKEY_CTX *ctx, int rfc5114);
147 int EVP_PKEY_CTX_set_dh_kdf_type(EVP_PKEY_CTX *ctx, int kdf);
148 int EVP_PKEY_CTX_get_dh_kdf_type(EVP_PKEY_CTX *ctx);
149 int EVP_PKEY_CTX_set0_dh_kdf_oid(EVP_PKEY_CTX *ctx, ASN1_OBJECT *oid);
150 int EVP_PKEY_CTX_get0_dh_kdf_oid(EVP_PKEY_CTX *ctx, ASN1_OBJECT **oid);
151 int EVP_PKEY_CTX_set_dh_kdf_md(EVP_PKEY_CTX *ctx, const EVP_MD *md);
152 int EVP_PKEY_CTX_get_dh_kdf_md(EVP_PKEY_CTX *ctx, const EVP_MD **md);
153 int EVP_PKEY_CTX_set_dh_kdf_outlen(EVP_PKEY_CTX *ctx, int len);
154 int EVP_PKEY_CTX_get_dh_kdf_outlen(EVP_PKEY_CTX *ctx, int *len);
155 int EVP_PKEY_CTX_set0_dh_kdf_ukm(EVP_PKEY_CTX *ctx, unsigned char *ukm, int len);
156 int EVP_PKEY_CTX_get0_dh_kdf_ukm(EVP_PKEY_CTX *ctx, unsigned char **ukm);
158 #include <openssl/ec.h>
160 int EVP_PKEY_CTX_set_ec_paramgen_curve_name(EVP_PKEY_CTX *ctx,
162 int EVP_PKEY_CTX_get_ec_paramgen_curve_name(EVP_PKEY_CTX *ctx,
163 char *name, size_t namelen);
164 int EVP_PKEY_CTX_set_ec_paramgen_curve_nid(EVP_PKEY_CTX *ctx, int nid);
165 int EVP_PKEY_CTX_set_ec_param_enc(EVP_PKEY_CTX *ctx, int param_enc);
166 int EVP_PKEY_CTX_set_ecdh_cofactor_mode(EVP_PKEY_CTX *ctx, int cofactor_mode);
167 int EVP_PKEY_CTX_get_ecdh_cofactor_mode(EVP_PKEY_CTX *ctx);
168 int EVP_PKEY_CTX_set_ecdh_kdf_type(EVP_PKEY_CTX *ctx, int kdf);
169 int EVP_PKEY_CTX_get_ecdh_kdf_type(EVP_PKEY_CTX *ctx);
170 int EVP_PKEY_CTX_set_ecdh_kdf_md(EVP_PKEY_CTX *ctx, const EVP_MD *md);
171 int EVP_PKEY_CTX_get_ecdh_kdf_md(EVP_PKEY_CTX *ctx, const EVP_MD **md);
172 int EVP_PKEY_CTX_set_ecdh_kdf_outlen(EVP_PKEY_CTX *ctx, int len);
173 int EVP_PKEY_CTX_get_ecdh_kdf_outlen(EVP_PKEY_CTX *ctx, int *len);
174 int EVP_PKEY_CTX_set0_ecdh_kdf_ukm(EVP_PKEY_CTX *ctx, unsigned char *ukm, int len);
175 int EVP_PKEY_CTX_get0_ecdh_kdf_ukm(EVP_PKEY_CTX *ctx, unsigned char **ukm);
177 int EVP_PKEY_CTX_set1_id(EVP_PKEY_CTX *ctx, void *id, size_t id_len);
178 int EVP_PKEY_CTX_get1_id(EVP_PKEY_CTX *ctx, void *id);
179 int EVP_PKEY_CTX_get1_id_len(EVP_PKEY_CTX *ctx, size_t *id_len);
183 The EVP_PKEY_CTX_get_params() and EVP_PKEY_CTX_set_params() functions get and
184 send arbitrary parameters from and to the algorithm implementation respectively.
185 Not all parameters may be supported by all providers.
186 See L<OSSL_PROVIDER(3)> for more information on providers.
187 See L<OSSL_PARAM(3)> for more information on parameters.
188 These functions must only be called after the EVP_PKEY_CTX has been initialised
189 for use in an operation.
191 The parameters currently supported by the default provider are:
195 =item "pad" (B<OSSL_EXCHANGE_PARAM_PAD>) <unsigned integer>
197 Sets the DH padding mode.
198 If B<OSSL_EXCHANGE_PARAM_PAD> is 1 then the shared secret is padded with zeros
199 up to the size of the DH prime I<p>.
200 If B<OSSL_EXCHANGE_PARAM_PAD> is zero (the default) then no padding is
203 =item "digest" (B<OSSL_SIGNATURE_PARAM_DIGEST>) <UTF8 string>
205 Gets and sets the name of the digest algorithm used for the input to the
208 =item "digest-size" (B<OSSL_SIGNATURE_PARAM_DIGEST_SIZE>) <unsigned integer>
210 Gets and sets the output size of the digest algorithm used for the input to the
212 The length of the "digest-size" parameter should not exceed that of a B<size_t>.
213 The internal algorithm that supports this parameter is DSA.
217 EVP_PKEY_CTX_gettable_params() and EVP_PKEY_CTX_settable_params() gets a
218 constant B<OSSL_PARAM> array that describes the gettable and
219 settable parameters for the current algorithm implementation, i.e. parameters
220 that can be used with EVP_PKEY_CTX_get_params() and EVP_PKEY_CTX_set_params()
222 See L<OSSL_PARAM(3)> for the use of B<OSSL_PARAM> as parameter descriptor.
223 These functions must only be called after the EVP_PKEY_CTX has been initialised
224 for use in an operation.
226 The function EVP_PKEY_CTX_ctrl() sends a control operation to the context
227 I<ctx>. The key type used must match I<keytype> if it is not -1. The parameter
228 I<optype> is a mask indicating which operations the control can be applied to.
229 The control command is indicated in I<cmd> and any additional arguments in
232 For I<cmd> = B<EVP_PKEY_CTRL_SET_MAC_KEY>, I<p1> is the length of the MAC key,
233 and I<p2> is the MAC key. This is used by Poly1305, SipHash, HMAC and CMAC.
235 Applications will not normally call EVP_PKEY_CTX_ctrl() directly but will
236 instead call one of the algorithm specific macros below.
238 The function EVP_PKEY_CTX_ctrl_uint64() is a wrapper that directly passes a
239 uint64 value as I<p2> to EVP_PKEY_CTX_ctrl().
241 The function EVP_PKEY_CTX_ctrl_str() allows an application to send an algorithm
242 specific control operation to a context I<ctx> in string form. This is
243 intended to be used for options specified on the command line or in text
244 files. The commands supported are documented in the openssl utility
245 command line pages for the option I<-pkeyopt> which is supported by the
246 I<pkeyutl>, I<genpkey> and I<req> commands.
248 The function EVP_PKEY_CTX_md() sends a message digest control operation
249 to the context I<ctx>. The message digest is specified by its name I<md>.
251 The EVP_PKEY_CTX_set_signature_md() function sets the message digest type used
252 in a signature. It can be used in the RSA, DSA and ECDSA algorithms.
254 The EVP_PKEY_CTX_get_signature_md() function gets the message digest type used
255 in a signature. It can be used in the RSA, DSA and ECDSA algorithms.
257 All the remaining "functions" are implemented as macros.
259 Key generation typically involves setting up parameters to be used and
260 generating the private and public key data. Some algorithm implementations
261 allow private key data to be set explicitly using the EVP_PKEY_CTX_set_mac_key()
262 macro. In this case key generation is simply the process of setting up the
263 parameters for the key and then setting the raw key data to the value explicitly
264 provided by that macro. Normally applications would call
265 L<EVP_PKEY_new_raw_private_key(3)> or similar functions instead of this macro.
267 The EVP_PKEY_CTX_set_mac_key() macro can be used with any of the algorithms
268 supported by the L<EVP_PKEY_new_raw_private_key(3)> function.
270 =head2 RSA parameters
272 The EVP_PKEY_CTX_set_rsa_padding() function sets the RSA padding mode for I<ctx>.
273 The I<pad> parameter can take the value B<RSA_PKCS1_PADDING> for PKCS#1
274 padding, B<RSA_SSLV23_PADDING> for SSLv23 padding, B<RSA_NO_PADDING> for
275 no padding, B<RSA_PKCS1_OAEP_PADDING> for OAEP padding (encrypt and
276 decrypt only), B<RSA_X931_PADDING> for X9.31 padding (signature operations
277 only), B<RSA_PKCS1_PSS_PADDING> (sign and verify only) and
278 B<RSA_PKCS1_WITH_TLS_PADDING> for TLS RSA ClientKeyExchange message padding
281 Two RSA padding modes behave differently if EVP_PKEY_CTX_set_signature_md()
282 is used. If this macro is called for PKCS#1 padding the plaintext buffer is
283 an actual digest value and is encapsulated in a DigestInfo structure according
284 to PKCS#1 when signing and this structure is expected (and stripped off) when
285 verifying. If this control is not used with RSA and PKCS#1 padding then the
286 supplied data is used directly and not encapsulated. In the case of X9.31
287 padding for RSA the algorithm identifier byte is added or checked and removed
288 if this control is called. If it is not called then the first byte of the plaintext
289 buffer is expected to be the algorithm identifier byte.
291 The EVP_PKEY_CTX_get_rsa_padding() function gets the RSA padding mode for I<ctx>.
293 The EVP_PKEY_CTX_set_rsa_pss_saltlen() function sets the RSA PSS salt
294 length to I<saltlen>. As its name implies it is only supported for PSS
295 padding. If this function is not called then the maximum salt length
296 is used when signing and auto detection when verifying. Three special
297 values are supported:
301 =item B<RSA_PSS_SALTLEN_DIGEST>
303 sets the salt length to the digest length.
305 =item B<RSA_PSS_SALTLEN_MAX>
307 sets the salt length to the maximum permissible value.
309 =item B<RSA_PSS_SALTLEN_AUTO>
311 causes the salt length to be automatically determined based on the
312 B<PSS> block structure when verifying. When signing, it has the same
313 meaning as B<RSA_PSS_SALTLEN_MAX>.
317 The EVP_PKEY_CTX_get_rsa_pss_saltlen() function gets the RSA PSS salt length
318 for I<ctx>. The padding mode must already have been set to
319 B<RSA_PKCS1_PSS_PADDING>.
321 The EVP_PKEY_CTX_set_rsa_keygen_bits() macro sets the RSA key length for
322 RSA key generation to I<bits>. If not specified 2048 bits is used.
324 The EVP_PKEY_CTX_set_rsa_keygen_pubexp() macro sets the public exponent value
325 for RSA key generation to I<pubexp>. Currently it should be an odd integer. The
326 I<pubexp> pointer is used internally by this function so it should not be
327 modified or freed after the call. If not specified 65537 is used.
329 The EVP_PKEY_CTX_set_rsa_keygen_primes() macro sets the number of primes for
330 RSA key generation to I<primes>. If not specified 2 is used.
332 The EVP_PKEY_CTX_set_rsa_mgf1_md_name() function sets the MGF1 digest for RSA
333 padding schemes to the digest named I<mdname>. If the RSA algorithm
334 implementation for the selected provider supports it then the digest will be
335 fetched using the properties I<mdprops>. If not explicitly set the signing
336 digest is used. The padding mode must have been set to B<RSA_PKCS1_OAEP_PADDING>
337 or B<RSA_PKCS1_PSS_PADDING>.
339 The EVP_PKEY_CTX_set_rsa_mgf1_md() function does the same as
340 EVP_PKEY_CTX_set_rsa_mgf1_md_name() except that the name of the digest is
341 inferred from the supplied I<md> and it is not possible to specify any
344 The EVP_PKEY_CTX_get_rsa_mgf1_md_name() function gets the name of the MGF1
345 digest algorithm for I<ctx>. If not explicitly set the signing digest is used.
346 The padding mode must have been set to B<RSA_PKCS1_OAEP_PADDING> or
347 B<RSA_PKCS1_PSS_PADDING>.
349 The EVP_PKEY_CTX_get_rsa_mgf1_md() function does the same as
350 EVP_PKEY_CTX_get_rsa_mgf1_md_name() except that it returns a pointer to an
351 EVP_MD object instead. Note that only known, built-in EVP_MD objects will be
352 returned. The EVP_MD object may be NULL if the digest is not one of these (such
353 as a digest only implemented in a third party provider).
355 The EVP_PKEY_CTX_set_rsa_oaep_md_name() function sets the message digest type
356 used in RSA OAEP to the digest named I<mdname>. If the RSA algorithm
357 implementation for the selected provider supports it then the digest will be
358 fetched using the properties I<mdprops>. The padding mode must have been set to
359 B<RSA_PKCS1_OAEP_PADDING>.
361 The EVP_PKEY_CTX_set_rsa_oaep_md() function does the same as
362 EVP_PKEY_CTX_set_rsa_oaep_md_name() except that the name of the digest is
363 inferred from the supplied I<md> and it is not possible to specify any
366 The EVP_PKEY_CTX_get_rsa_oaep_md_name() function gets the message digest
367 algorithm name used in RSA OAEP and stores it in the buffer I<name> which is of
368 size I<namelen>. The padding mode must have been set to
369 B<RSA_PKCS1_OAEP_PADDING>. The buffer should be sufficiently large for any
370 expected digest algorithm names or the function will fail.
372 The EVP_PKEY_CTX_get_rsa_oaep_md() function does the same as
373 EVP_PKEY_CTX_get_rsa_oaep_md_name() except that it returns a pointer to an
374 EVP_MD object instead. Note that only known, built-in EVP_MD objects will be
375 returned. The EVP_MD object may be NULL if the digest is not one of these (such
376 as a digest only implemented in a third party provider).
378 The EVP_PKEY_CTX_set0_rsa_oaep_label() function sets the RSA OAEP label to
379 I<label> and its length to I<len>. If I<label> is NULL or I<len> is 0,
380 the label is cleared. The library takes ownership of the label so the
381 caller should not free the original memory pointed to by I<label>.
382 The padding mode must have been set to B<RSA_PKCS1_OAEP_PADDING>.
384 The EVP_PKEY_CTX_get0_rsa_oaep_label() function gets the RSA OAEP label to
385 I<label>. The return value is the label length. The padding mode
386 must have been set to B<RSA_PKCS1_OAEP_PADDING>. The resulting pointer is owned
387 by the library and should not be freed by the caller.
389 B<RSA_PKCS1_WITH_TLS_PADDING> is used when decrypting an RSA encrypted TLS
390 pre-master secret in a TLS ClientKeyExchange message. It is the same as
391 RSA_PKCS1_PADDING except that it additionally verifies that the result is the
392 correct length and the first two bytes are the protocol version initially
393 requested by the client. If the encrypted content is publicly invalid then the
394 decryption will fail. However, if the padding checks fail then decryption will
395 still appear to succeed but a random TLS premaster secret will be returned
396 instead. This padding mode accepts two parameters which can be set using the
397 L<EVP_PKEY_CTX_set_params(3)> function. These are
398 OSSL_ASYM_CIPHER_PARAM_TLS_CLIENT_VERSION and
399 OSSL_ASYM_CIPHER_PARAM_TLS_NEGOTIATED_VERSION, both of which are expected to be
400 unsigned integers. Normally only the first of these will be set and represents
401 the TLS protocol version that was first requested by the client (e.g. 0x0303 for
402 TLSv1.2, 0x0302 for TLSv1.1 etc). Historically some buggy clients would use the
403 negotiated protocol version instead of the protocol version first requested. If
404 this behaviour should be tolerated then
405 OSSL_ASYM_CIPHER_PARAM_TLS_NEGOTIATED_VERSION should be set to the actual
406 negotiated protocol version. Otherwise it should be left unset.
408 =head2 DSA parameters
410 The EVP_PKEY_CTX_set_dsa_paramgen_bits() method sets the number of bits used
411 for DSA parameter generation to I<nbits>. If not specified, 2048 is used.
413 The EVP_PKEY_CTX_set_dsa_paramgen_q_bits() method sets the number of bits in the
414 subprime parameter I<q> for DSA parameter generation to I<qbits>. If not
415 specified, 224 is used. If a digest function is specified below, this parameter
416 is ignored and instead, the number of bits in I<q> matches the size of the
419 The EVP_PKEY_CTX_set_dsa_paramgen_md() method sets the digest function used for
420 DSA parameter generation to I<md>. If not specified, one of SHA-1, SHA-224, or
421 SHA-256 is selected to match the bit length of I<q> above.
423 The EVP_PKEY_CTX_set_dsa_paramgen_md_props() method sets the digest function
424 used for DSA parameter generation using I<md_name> and I<md_properties> to
425 retrieve the digest from a provider.
426 If not specified, I<md_name> will be set to one of SHA-1, SHA-224, or
427 SHA-256 depending on the bit length of I<q> above. I<md_properties> is a
428 property query string that has a default value of '' if not specified.
430 The EVP_PKEY_CTX_set_dsa_paramgen_gindex() method sets the I<gindex> used by
431 the generator G. The default value is -1 which uses unverifiable g, otherwise
432 a positive value uses verifiable g. This value must be saved if key validation
433 of g is required, since it is not part of a persisted key.
435 The EVP_PKEY_CTX_set_dsa_paramgen_seed() method sets the I<seed> to use for
436 generation rather than using a randomly generated value for the seed. This is
437 useful for testing purposes only and can fail if the seed does not produce
438 primes for both p & q on its first iteration. This value must be saved if
439 key validation of p, q, and verifiable g are required, since it is not part of
442 The EVP_PKEY_CTX_set_dsa_paramgen_type() method sets the generation type to
443 use FIPS186-4 generation if I<name> is "fips186_4", or FIPS186-2 generation if
444 I<name> is "fips186_2". The default value is "fips186_4".
448 The EVP_PKEY_CTX_set_dh_paramgen_prime_len() macro sets the length of the DH
449 prime parameter I<p> for DH parameter generation. If this macro is not called
450 then 2048 is used. Only accepts lengths greater than or equal to 256.
452 The EVP_PKEY_CTX_set_dh_paramgen_subprime_len() macro sets the length of the DH
453 optional subprime parameter I<q> for DH parameter generation. The default is
454 256 if the prime is at least 2048 bits long or 160 otherwise. The DH
455 paramgen type must have been set to "fips186_4".
457 The EVP_PKEY_CTX_set_dh_paramgen_generator() macro sets DH generator to I<gen>
458 for DH parameter generation. If not specified 2 is used.
460 The EVP_PKEY_CTX_set_dh_paramgen_type() macro sets the key type for DH
461 parameter generation. The supported parameters are:
465 =item B<DH_PARAMGEN_TYPE_GENERATOR>
467 Uses a generator g (PKCS#3 format).
469 =item B<DH_PARAMGEN_TYPE_FIPS_186_2>
471 FIPS186-2 FFC parameter generator (X9.42 DH).
473 =item B<DH_PARAMGEN_TYPE_FIPS_186_4>
475 FIPS186-4 FFC parameter generator.
479 The default is B<DH_PARAMGEN_TYPE_GENERATOR>.
481 The EVP_PKEY_CTX_set_dh_pad() function sets the DH padding mode.
482 If I<pad> is 1 the shared secret is padded with zeros up to the size of the DH
484 If I<pad> is zero (the default) then no padding is performed.
486 EVP_PKEY_CTX_set_dh_nid() sets the DH parameters to values corresponding to
487 I<nid> as defined in RFC7919 or RFC3526. The I<nid> parameter must be
488 B<NID_ffdhe2048>, B<NID_ffdhe3072>, B<NID_ffdhe4096>, B<NID_ffdhe6144>,
489 B<NID_ffdhe8192>, B<NID_modp_1536>, B<NID_modp_2048>, B<NID_modp_3072>,
490 B<NID_modp_4096>, B<NID_modp_6144>, B<NID_modp_8192> or B<NID_undef> to clear
491 the stored value. This macro can be called during parameter or key generation.
492 The nid parameter and the rfc5114 parameter are mutually exclusive.
494 The EVP_PKEY_CTX_set_dh_rfc5114() and EVP_PKEY_CTX_set_dhx_rfc5114() macros are
495 synonymous. They set the DH parameters to the values defined in RFC5114. The
496 I<rfc5114> parameter must be 1, 2 or 3 corresponding to RFC5114 sections
497 2.1, 2.2 and 2.3. or 0 to clear the stored value. This macro can be called
498 during parameter generation. The I<ctx> must have a key type of
500 The rfc5114 parameter and the nid parameter are mutually exclusive.
502 =head2 DH key derivation function parameters
504 Note that all of the following functions require that the I<ctx> parameter has
505 a private key type of B<EVP_PKEY_DHX>. When using key derivation, the output of
506 EVP_PKEY_derive() is the output of the KDF instead of the DH shared secret.
507 The KDF output is typically used as a Key Encryption Key (KEK) that in turn
508 encrypts a Content Encryption Key (CEK).
510 The EVP_PKEY_CTX_set_dh_kdf_type() macro sets the key derivation function type
511 to I<kdf> for DH key derivation. Possible values are B<EVP_PKEY_DH_KDF_NONE>
512 and B<EVP_PKEY_DH_KDF_X9_42> which uses the key derivation specified in RFC2631
513 (based on the keying algorithm described in X9.42). When using key derivation,
514 the I<kdf_oid>, I<kdf_md> and I<kdf_outlen> parameters must also be specified.
516 The EVP_PKEY_CTX_get_dh_kdf_type() macro gets the key derivation function type
517 for I<ctx> used for DH key derivation. Possible values are B<EVP_PKEY_DH_KDF_NONE>
518 and B<EVP_PKEY_DH_KDF_X9_42>.
520 The EVP_PKEY_CTX_set0_dh_kdf_oid() macro sets the key derivation function
521 object identifier to I<oid> for DH key derivation. This OID should identify
522 the algorithm to be used with the Content Encryption Key.
523 The library takes ownership of the object identifier so the caller should not
524 free the original memory pointed to by I<oid>.
526 The EVP_PKEY_CTX_get0_dh_kdf_oid() macro gets the key derivation function oid
527 for I<ctx> used for DH key derivation. The resulting pointer is owned by the
528 library and should not be freed by the caller.
530 The EVP_PKEY_CTX_set_dh_kdf_md() macro sets the key derivation function
531 message digest to I<md> for DH key derivation. Note that RFC2631 specifies
532 that this digest should be SHA1 but OpenSSL tolerates other digests.
534 The EVP_PKEY_CTX_get_dh_kdf_md() macro gets the key derivation function
535 message digest for I<ctx> used for DH key derivation.
537 The EVP_PKEY_CTX_set_dh_kdf_outlen() macro sets the key derivation function
538 output length to I<len> for DH key derivation.
540 The EVP_PKEY_CTX_get_dh_kdf_outlen() macro gets the key derivation function
541 output length for I<ctx> used for DH key derivation.
543 The EVP_PKEY_CTX_set0_dh_kdf_ukm() macro sets the user key material to
544 I<ukm> and its length to I<len> for DH key derivation. This parameter is optional
545 and corresponds to the partyAInfo field in RFC2631 terms. The specification
546 requires that it is 512 bits long but this is not enforced by OpenSSL.
547 The library takes ownership of the user key material so the caller should not
548 free the original memory pointed to by I<ukm>.
550 The EVP_PKEY_CTX_get0_dh_kdf_ukm() macro gets the user key material for I<ctx>.
551 The return value is the user key material length. The resulting pointer is owned
552 by the library and should not be freed by the caller.
556 EVP_PKEY_CTX_set_ec_paramgen_curve_name() sets the EC curve to I<name> for EC
557 parameter generation.
559 EVP_PKEY_CTX_set_ec_paramgen_curve_nid() does the same as
560 EVP_PKEY_CTX_set_ec_paramgen_curve_name(), but uses a I<nid> rather than a
563 For EC parameter generation, one of EVP_PKEY_CTX_set_ec_paramgen_curve_name()
564 or EVP_PKEY_CTX_set_ec_paramgen_curve_nid() must be called or an error occurs
565 because there is no default curve.
566 These function can also be called to set the curve explicitly when
567 generating an EC key.
569 EVP_PKEY_CTX_get_ec_paramgen_curve_name() finds the curve name that's currently
570 set with I<ctx>, and writes it to the location that I<name> points at, as long
571 as its size I<namelen> is large enough to store that name, including a
572 terminating NUL byte.
574 The EVP_PKEY_CTX_set_ec_param_enc() macro sets the EC parameter encoding to
575 I<param_enc> when generating EC parameters or an EC key. The encoding can be
576 B<OPENSSL_EC_EXPLICIT_CURVE> for explicit parameters (the default in versions
577 of OpenSSL before 1.1.0) or B<OPENSSL_EC_NAMED_CURVE> to use named curve form.
578 For maximum compatibility the named curve form should be used. Note: the
579 B<OPENSSL_EC_NAMED_CURVE> value was added in OpenSSL 1.1.0; previous
580 versions should use 0 instead.
582 =head2 ECDH parameters
584 The EVP_PKEY_CTX_set_ecdh_cofactor_mode() macro sets the cofactor mode to
585 I<cofactor_mode> for ECDH key derivation. Possible values are 1 to enable
586 cofactor key derivation, 0 to disable it and -1 to clear the stored cofactor
587 mode and fallback to the private key cofactor mode.
589 The EVP_PKEY_CTX_get_ecdh_cofactor_mode() macro returns the cofactor mode for
590 I<ctx> used for ECDH key derivation. Possible values are 1 when cofactor key
591 derivation is enabled and 0 otherwise.
593 =head2 ECDH key derivation function parameters
595 The EVP_PKEY_CTX_set_ecdh_kdf_type() macro sets the key derivation function type
596 to I<kdf> for ECDH key derivation. Possible values are B<EVP_PKEY_ECDH_KDF_NONE>
597 and B<EVP_PKEY_ECDH_KDF_X9_63> which uses the key derivation specified in X9.63.
598 When using key derivation, the I<kdf_md> and I<kdf_outlen> parameters must
601 The EVP_PKEY_CTX_get_ecdh_kdf_type() macro returns the key derivation function
602 type for I<ctx> used for ECDH key derivation. Possible values are
603 B<EVP_PKEY_ECDH_KDF_NONE> and B<EVP_PKEY_ECDH_KDF_X9_63>.
605 The EVP_PKEY_CTX_set_ecdh_kdf_md() macro sets the key derivation function
606 message digest to I<md> for ECDH key derivation. Note that X9.63 specifies
607 that this digest should be SHA1 but OpenSSL tolerates other digests.
609 The EVP_PKEY_CTX_get_ecdh_kdf_md() macro gets the key derivation function
610 message digest for I<ctx> used for ECDH key derivation.
612 The EVP_PKEY_CTX_set_ecdh_kdf_outlen() macro sets the key derivation function
613 output length to I<len> for ECDH key derivation.
615 The EVP_PKEY_CTX_get_ecdh_kdf_outlen() macro gets the key derivation function
616 output length for I<ctx> used for ECDH key derivation.
618 The EVP_PKEY_CTX_set0_ecdh_kdf_ukm() macro sets the user key material to I<ukm>
619 for ECDH key derivation. This parameter is optional and corresponds to the
620 shared info in X9.63 terms. The library takes ownership of the user key material
621 so the caller should not free the original memory pointed to by I<ukm>.
623 The EVP_PKEY_CTX_get0_ecdh_kdf_ukm() macro gets the user key material for I<ctx>.
624 The return value is the user key material length. The resulting pointer is owned
625 by the library and should not be freed by the caller.
627 =head2 Other parameters
629 The EVP_PKEY_CTX_set1_id(), EVP_PKEY_CTX_get1_id() and EVP_PKEY_CTX_get1_id_len()
630 macros are used to manipulate the special identifier field for specific signature
631 algorithms such as SM2. The EVP_PKEY_CTX_set1_id() sets an ID pointed by I<id> with
632 the length I<id_len> to the library. The library takes a copy of the id so that
633 the caller can safely free the original memory pointed to by I<id>. The
634 EVP_PKEY_CTX_get1_id_len() macro returns the length of the ID set via a previous
635 call to EVP_PKEY_CTX_set1_id(). The length is usually used to allocate adequate
636 memory for further calls to EVP_PKEY_CTX_get1_id(). The EVP_PKEY_CTX_get1_id()
637 macro returns the previously set ID value to caller in I<id>. The caller should
638 allocate adequate memory space for the I<id> before calling EVP_PKEY_CTX_get1_id().
642 EVP_PKEY_CTX_set_params() returns 1 for success or 0 otherwise.
643 EVP_PKEY_CTX_settable_params() returns an OSSL_PARAM array on success or NULL on
645 It may also return NULL if there are no settable parameters available.
647 All other functions and macros described on this page return a positive value
648 for success and 0 or a negative value for failure. In particular a return value
649 of -2 indicates the operation is not supported by the public key algorithm.
653 L<EVP_PKEY_CTX_new(3)>,
654 L<EVP_PKEY_encrypt(3)>,
655 L<EVP_PKEY_decrypt(3)>,
657 L<EVP_PKEY_verify(3)>,
658 L<EVP_PKEY_verify_recover(3)>,
659 L<EVP_PKEY_derive(3)>,
660 L<EVP_PKEY_keygen(3)>
664 EVP_PKEY_CTX_get_signature_md(), EVP_PKEY_CTX_set_signature_md(),
665 EVP_PKEY_CTX_set_dh_pad(), EVP_PKEY_CTX_set_rsa_padding(),
666 EVP_PKEY_CTX_get_rsa_padding(), EVP_PKEY_CTX_get_rsa_mgf1_md(),
667 EVP_PKEY_CTX_set_rsa_mgf1_md(), EVP_PKEY_CTX_set_rsa_oaep_md(),
668 EVP_PKEY_CTX_get_rsa_oaep_md(), EVP_PKEY_CTX_set0_rsa_oaep_label(),
669 EVP_PKEY_CTX_get0_rsa_oaep_label(), EVP_PKEY_CTX_set_rsa_pss_saltlen(),
670 EVP_PKEY_CTX_get_rsa_pss_saltlen(), EVP_PKEY_CTX_set_dsa_paramgen_bits(),
671 EVP_PKEY_CTX_set_dsa_paramgen_q_bits() and EVP_PKEY_CTX_set_dsa_paramgen_md()
672 were macros in OpenSSL 1.1.1 and below.
673 From OpenSSL 3.0 they are functions.
675 EVP_PKEY_CTX_get_rsa_oaep_md_name(), EVP_PKEY_CTX_get_rsa_mgf1_md_name(),
676 EVP_PKEY_CTX_set_rsa_mgf1_md_name(), EVP_PKEY_CTX_set_rsa_oaep_md_name(),
677 EVP_PKEY_CTX_set_dsa_paramgen_md_props(), EVP_PKEY_CTX_set_dsa_paramgen_gindex(),
678 EVP_PKEY_CTX_set_dsa_paramgen_type() and EVP_PKEY_CTX_set_dsa_paramgen_seed()
679 were added in OpenSSL 3.0.
681 The EVP_PKEY_CTX_set1_id(), EVP_PKEY_CTX_get1_id() and
682 EVP_PKEY_CTX_get1_id_len() macros were added in 1.1.1, other functions were
683 added in OpenSSL 1.0.0.
687 Copyright 2006-2020 The OpenSSL Project Authors. All Rights Reserved.
689 Licensed under the Apache License 2.0 (the "License"). You may not use
690 this file except in compliance with the License. You can obtain a copy
691 in the file LICENSE in the source distribution or at
692 L<https://www.openssl.org/source/license.html>.