1EVP_PKEY_CTX_CTRL(3ossl)            OpenSSL           EVP_PKEY_CTX_CTRL(3ossl)
2
3
4

NAME

6       EVP_PKEY_CTX_ctrl, EVP_PKEY_CTX_ctrl_str, EVP_PKEY_CTX_ctrl_uint64,
7       EVP_PKEY_CTX_md, EVP_PKEY_CTX_set_signature_md,
8       EVP_PKEY_CTX_get_signature_md, EVP_PKEY_CTX_set_mac_key,
9       EVP_PKEY_CTX_set_group_name, EVP_PKEY_CTX_get_group_name,
10       EVP_PKEY_CTX_set_rsa_padding, EVP_PKEY_CTX_get_rsa_padding,
11       EVP_PKEY_CTX_set_rsa_pss_saltlen, EVP_PKEY_CTX_get_rsa_pss_saltlen,
12       EVP_PKEY_CTX_set_rsa_keygen_bits, EVP_PKEY_CTX_set_rsa_keygen_pubexp,
13       EVP_PKEY_CTX_set1_rsa_keygen_pubexp,
14       EVP_PKEY_CTX_set_rsa_keygen_primes, EVP_PKEY_CTX_set_rsa_mgf1_md_name,
15       EVP_PKEY_CTX_set_rsa_mgf1_md, EVP_PKEY_CTX_get_rsa_mgf1_md,
16       EVP_PKEY_CTX_get_rsa_mgf1_md_name, EVP_PKEY_CTX_set_rsa_oaep_md_name,
17       EVP_PKEY_CTX_set_rsa_oaep_md, EVP_PKEY_CTX_get_rsa_oaep_md,
18       EVP_PKEY_CTX_get_rsa_oaep_md_name, EVP_PKEY_CTX_set0_rsa_oaep_label,
19       EVP_PKEY_CTX_get0_rsa_oaep_label, EVP_PKEY_CTX_set_dsa_paramgen_bits,
20       EVP_PKEY_CTX_set_dsa_paramgen_q_bits, EVP_PKEY_CTX_set_dsa_paramgen_md,
21       EVP_PKEY_CTX_set_dsa_paramgen_md_props,
22       EVP_PKEY_CTX_set_dsa_paramgen_gindex,
23       EVP_PKEY_CTX_set_dsa_paramgen_type, EVP_PKEY_CTX_set_dsa_paramgen_seed,
24       EVP_PKEY_CTX_set_dh_paramgen_prime_len,
25       EVP_PKEY_CTX_set_dh_paramgen_subprime_len,
26       EVP_PKEY_CTX_set_dh_paramgen_generator,
27       EVP_PKEY_CTX_set_dh_paramgen_type, EVP_PKEY_CTX_set_dh_paramgen_gindex,
28       EVP_PKEY_CTX_set_dh_paramgen_seed, EVP_PKEY_CTX_set_dh_rfc5114,
29       EVP_PKEY_CTX_set_dhx_rfc5114, EVP_PKEY_CTX_set_dh_pad,
30       EVP_PKEY_CTX_set_dh_nid, EVP_PKEY_CTX_set_dh_kdf_type,
31       EVP_PKEY_CTX_get_dh_kdf_type, EVP_PKEY_CTX_set0_dh_kdf_oid,
32       EVP_PKEY_CTX_get0_dh_kdf_oid, EVP_PKEY_CTX_set_dh_kdf_md,
33       EVP_PKEY_CTX_get_dh_kdf_md, EVP_PKEY_CTX_set_dh_kdf_outlen,
34       EVP_PKEY_CTX_get_dh_kdf_outlen, EVP_PKEY_CTX_set0_dh_kdf_ukm,
35       EVP_PKEY_CTX_get0_dh_kdf_ukm, EVP_PKEY_CTX_set_ec_paramgen_curve_nid,
36       EVP_PKEY_CTX_set_ec_param_enc, EVP_PKEY_CTX_set_ecdh_cofactor_mode,
37       EVP_PKEY_CTX_get_ecdh_cofactor_mode, EVP_PKEY_CTX_set_ecdh_kdf_type,
38       EVP_PKEY_CTX_get_ecdh_kdf_type, EVP_PKEY_CTX_set_ecdh_kdf_md,
39       EVP_PKEY_CTX_get_ecdh_kdf_md, EVP_PKEY_CTX_set_ecdh_kdf_outlen,
40       EVP_PKEY_CTX_get_ecdh_kdf_outlen, EVP_PKEY_CTX_set0_ecdh_kdf_ukm,
41       EVP_PKEY_CTX_get0_ecdh_kdf_ukm, EVP_PKEY_CTX_set1_id,
42       EVP_PKEY_CTX_get1_id, EVP_PKEY_CTX_get1_id_len, EVP_PKEY_CTX_set_kem_op
43       - algorithm specific control operations
44

SYNOPSIS

46        #include <openssl/evp.h>
47
48        int EVP_PKEY_CTX_ctrl(EVP_PKEY_CTX *ctx, int keytype, int optype,
49                              int cmd, int p1, void *p2);
50        int EVP_PKEY_CTX_ctrl_uint64(EVP_PKEY_CTX *ctx, int keytype, int optype,
51                                     int cmd, uint64_t value);
52        int EVP_PKEY_CTX_ctrl_str(EVP_PKEY_CTX *ctx, const char *type,
53                                  const char *value);
54
55        int EVP_PKEY_CTX_md(EVP_PKEY_CTX *ctx, int optype, int cmd, const char *md);
56
57        int EVP_PKEY_CTX_set_signature_md(EVP_PKEY_CTX *ctx, const EVP_MD *md);
58        int EVP_PKEY_CTX_get_signature_md(EVP_PKEY_CTX *ctx, const EVP_MD **pmd);
59
60        int EVP_PKEY_CTX_set_mac_key(EVP_PKEY_CTX *ctx, const unsigned char *key,
61                                     int len);
62        int EVP_PKEY_CTX_set_group_name(EVP_PKEY_CTX *ctx, const char *name);
63        int EVP_PKEY_CTX_get_group_name(EVP_PKEY_CTX *ctx, char *name, size_t namelen);
64
65        int EVP_PKEY_CTX_set_kem_op(EVP_PKEY_CTX *ctx, const char *op);
66
67        #include <openssl/rsa.h>
68
69        int EVP_PKEY_CTX_set_rsa_padding(EVP_PKEY_CTX *ctx, int pad);
70        int EVP_PKEY_CTX_get_rsa_padding(EVP_PKEY_CTX *ctx, int *pad);
71        int EVP_PKEY_CTX_set_rsa_pss_saltlen(EVP_PKEY_CTX *ctx, int saltlen);
72        int EVP_PKEY_CTX_get_rsa_pss_saltlen(EVP_PKEY_CTX *ctx, int *saltlen);
73        int EVP_PKEY_CTX_set_rsa_keygen_bits(EVP_PKEY_CTX *ctx, int mbits);
74        int EVP_PKEY_CTX_set1_rsa_keygen_pubexp(EVP_PKEY_CTX *ctx, BIGNUM *pubexp);
75        int EVP_PKEY_CTX_set_rsa_keygen_primes(EVP_PKEY_CTX *ctx, int primes);
76        int EVP_PKEY_CTX_set_rsa_mgf1_md_name(EVP_PKEY_CTX *ctx, const char *mdname,
77                                            const char *mdprops);
78        int EVP_PKEY_CTX_set_rsa_mgf1_md(EVP_PKEY_CTX *ctx, const EVP_MD *md);
79        int EVP_PKEY_CTX_get_rsa_mgf1_md(EVP_PKEY_CTX *ctx, const EVP_MD **md);
80        int EVP_PKEY_CTX_get_rsa_mgf1_md_name(EVP_PKEY_CTX *ctx, char *name,
81                                              size_t namelen);
82        int EVP_PKEY_CTX_set_rsa_oaep_md_name(EVP_PKEY_CTX *ctx, const char *mdname,
83                                              const char *mdprops);
84        int EVP_PKEY_CTX_set_rsa_oaep_md(EVP_PKEY_CTX *ctx, const EVP_MD *md);
85        int EVP_PKEY_CTX_get_rsa_oaep_md(EVP_PKEY_CTX *ctx, const EVP_MD **md);
86        int EVP_PKEY_CTX_get_rsa_oaep_md_name(EVP_PKEY_CTX *ctx, char *name,
87                                              size_t namelen);
88        int EVP_PKEY_CTX_set0_rsa_oaep_label(EVP_PKEY_CTX *ctx, void *label,
89                                             int len);
90        int EVP_PKEY_CTX_get0_rsa_oaep_label(EVP_PKEY_CTX *ctx, unsigned char **label);
91
92        #include <openssl/dsa.h>
93
94        int EVP_PKEY_CTX_set_dsa_paramgen_bits(EVP_PKEY_CTX *ctx, int nbits);
95        int EVP_PKEY_CTX_set_dsa_paramgen_q_bits(EVP_PKEY_CTX *ctx, int qbits);
96        int EVP_PKEY_CTX_set_dsa_paramgen_md(EVP_PKEY_CTX *ctx, const EVP_MD *md);
97        int EVP_PKEY_CTX_set_dsa_paramgen_md_props(EVP_PKEY_CTX *ctx,
98                                                   const char *md_name,
99                                                   const char *md_properties);
100        int EVP_PKEY_CTX_set_dsa_paramgen_type(EVP_PKEY_CTX *ctx, const char *name);
101        int EVP_PKEY_CTX_set_dsa_paramgen_gindex(EVP_PKEY_CTX *ctx, int gindex);
102        int EVP_PKEY_CTX_set_dsa_paramgen_seed(EVP_PKEY_CTX *ctx,
103                                               const unsigned char *seed,
104                                               size_t seedlen);
105
106        #include <openssl/dh.h>
107
108        int EVP_PKEY_CTX_set_dh_paramgen_prime_len(EVP_PKEY_CTX *ctx, int len);
109        int EVP_PKEY_CTX_set_dh_paramgen_subprime_len(EVP_PKEY_CTX *ctx, int len);
110        int EVP_PKEY_CTX_set_dh_paramgen_generator(EVP_PKEY_CTX *ctx, int gen);
111        int EVP_PKEY_CTX_set_dh_paramgen_type(EVP_PKEY_CTX *ctx, int type);
112        int EVP_PKEY_CTX_set_dh_pad(EVP_PKEY_CTX *ctx, int pad);
113        int EVP_PKEY_CTX_set_dh_nid(EVP_PKEY_CTX *ctx, int nid);
114        int EVP_PKEY_CTX_set_dh_rfc5114(EVP_PKEY_CTX *ctx, int rfc5114);
115        int EVP_PKEY_CTX_set_dhx_rfc5114(EVP_PKEY_CTX *ctx, int rfc5114);
116        int EVP_PKEY_CTX_set_dh_paramgen_gindex(EVP_PKEY_CTX *ctx, int gindex);
117        int EVP_PKEY_CTX_set_dh_paramgen_seed(EVP_PKEY_CTX *ctx,
118                                               const unsigned char *seed,
119                                               size_t seedlen);
120        int EVP_PKEY_CTX_set_dh_kdf_type(EVP_PKEY_CTX *ctx, int kdf);
121        int EVP_PKEY_CTX_get_dh_kdf_type(EVP_PKEY_CTX *ctx);
122        int EVP_PKEY_CTX_set0_dh_kdf_oid(EVP_PKEY_CTX *ctx, ASN1_OBJECT *oid);
123        int EVP_PKEY_CTX_get0_dh_kdf_oid(EVP_PKEY_CTX *ctx, ASN1_OBJECT **oid);
124        int EVP_PKEY_CTX_set_dh_kdf_md(EVP_PKEY_CTX *ctx, const EVP_MD *md);
125        int EVP_PKEY_CTX_get_dh_kdf_md(EVP_PKEY_CTX *ctx, const EVP_MD **md);
126        int EVP_PKEY_CTX_set_dh_kdf_outlen(EVP_PKEY_CTX *ctx, int len);
127        int EVP_PKEY_CTX_get_dh_kdf_outlen(EVP_PKEY_CTX *ctx, int *len);
128        int EVP_PKEY_CTX_set0_dh_kdf_ukm(EVP_PKEY_CTX *ctx, unsigned char *ukm, int len);
129
130        #include <openssl/ec.h>
131
132        int EVP_PKEY_CTX_set_ec_paramgen_curve_nid(EVP_PKEY_CTX *ctx, int nid);
133        int EVP_PKEY_CTX_set_ec_param_enc(EVP_PKEY_CTX *ctx, int param_enc);
134        int EVP_PKEY_CTX_set_ecdh_cofactor_mode(EVP_PKEY_CTX *ctx, int cofactor_mode);
135        int EVP_PKEY_CTX_get_ecdh_cofactor_mode(EVP_PKEY_CTX *ctx);
136        int EVP_PKEY_CTX_set_ecdh_kdf_type(EVP_PKEY_CTX *ctx, int kdf);
137        int EVP_PKEY_CTX_get_ecdh_kdf_type(EVP_PKEY_CTX *ctx);
138        int EVP_PKEY_CTX_set_ecdh_kdf_md(EVP_PKEY_CTX *ctx, const EVP_MD *md);
139        int EVP_PKEY_CTX_get_ecdh_kdf_md(EVP_PKEY_CTX *ctx, const EVP_MD **md);
140        int EVP_PKEY_CTX_set_ecdh_kdf_outlen(EVP_PKEY_CTX *ctx, int len);
141        int EVP_PKEY_CTX_get_ecdh_kdf_outlen(EVP_PKEY_CTX *ctx, int *len);
142        int EVP_PKEY_CTX_set0_ecdh_kdf_ukm(EVP_PKEY_CTX *ctx, unsigned char *ukm, int len);
143
144        int EVP_PKEY_CTX_set1_id(EVP_PKEY_CTX *ctx, void *id, size_t id_len);
145        int EVP_PKEY_CTX_get1_id(EVP_PKEY_CTX *ctx, void *id);
146        int EVP_PKEY_CTX_get1_id_len(EVP_PKEY_CTX *ctx, size_t *id_len);
147
148       The following functions have been deprecated since OpenSSL 3.0, and can
149       be hidden entirely by defining OPENSSL_API_COMPAT with a suitable
150       version value, see openssl_user_macros(7):
151
152        #include <openssl/rsa.h>
153
154        int EVP_PKEY_CTX_set_rsa_keygen_pubexp(EVP_PKEY_CTX *ctx, BIGNUM *pubexp);
155
156        #include <openssl/dh.h>
157
158        int EVP_PKEY_CTX_get0_dh_kdf_ukm(EVP_PKEY_CTX *ctx, unsigned char **ukm);
159
160        #include <openssl/ec.h>
161
162        int EVP_PKEY_CTX_get0_ecdh_kdf_ukm(EVP_PKEY_CTX *ctx, unsigned char **ukm);
163

DESCRIPTION

165       EVP_PKEY_CTX_ctrl() sends a control operation to the context ctx. The
166       key type used must match keytype if it is not -1. The parameter optype
167       is a mask indicating which operations the control can be applied to.
168       The control command is indicated in cmd and any additional arguments in
169       p1 and p2.
170
171       For cmd = EVP_PKEY_CTRL_SET_MAC_KEY, p1 is the length of the MAC key,
172       and p2 is the MAC key. This is used by Poly1305, SipHash, HMAC and
173       CMAC.
174
175       Applications will not normally call EVP_PKEY_CTX_ctrl() directly but
176       will instead call one of the algorithm specific functions below.
177
178       EVP_PKEY_CTX_ctrl_uint64() is a wrapper that directly passes a uint64
179       value as p2 to EVP_PKEY_CTX_ctrl().
180
181       EVP_PKEY_CTX_ctrl_str() allows an application to send an algorithm
182       specific control operation to a context ctx in string form. This is
183       intended to be used for options specified on the command line or in
184       text files. The commands supported are documented in the openssl
185       utility command line pages for the option -pkeyopt which is supported
186       by the pkeyutl, genpkey and req commands.
187
188       EVP_PKEY_CTX_md() sends a message digest control operation to the
189       context ctx. The message digest is specified by its name md.
190
191       EVP_PKEY_CTX_set_signature_md() sets the message digest type used in a
192       signature. It can be used in the RSA, DSA and ECDSA algorithms.
193
194       EVP_PKEY_CTX_get_signature_md()gets the message digest type used in a
195       signature. It can be used in the RSA, DSA and ECDSA algorithms.
196
197       Key generation typically involves setting up parameters to be used and
198       generating the private and public key data. Some algorithm
199       implementations allow private key data to be set explicitly using
200       EVP_PKEY_CTX_set_mac_key().  In this case key generation is simply the
201       process of setting up the parameters for the key and then setting the
202       raw key data to the value explicitly.  Normally applications would call
203       EVP_PKEY_new_raw_private_key(3) or similar functions instead.
204
205       EVP_PKEY_CTX_set_mac_key() can be used with any of the algorithms
206       supported by the EVP_PKEY_new_raw_private_key(3) function.
207
208       EVP_PKEY_CTX_set_group_name() sets the group name to name for parameter
209       and key generation. For example for EC keys this will set the curve
210       name and for DH keys it will set the name of the finite field group.
211
212       EVP_PKEY_CTX_get_group_name() finds the group name that's currently set
213       with ctx, and writes it to the location that name points at, as long as
214       its size namelen is large enough to store that name, including a
215       terminating NUL byte.
216
217   RSA parameters
218       EVP_PKEY_CTX_set_rsa_padding() sets the RSA padding mode for ctx.  The
219       pad parameter can take the value RSA_PKCS1_PADDING for PKCS#1 padding,
220       RSA_NO_PADDING for no padding, RSA_PKCS1_OAEP_PADDING for OAEP padding
221       (encrypt and decrypt only), RSA_X931_PADDING for X9.31 padding
222       (signature operations only), RSA_PKCS1_PSS_PADDING (sign and verify
223       only) and RSA_PKCS1_WITH_TLS_PADDING for TLS RSA ClientKeyExchange
224       message padding (decryption only).
225
226       Two RSA padding modes behave differently if
227       EVP_PKEY_CTX_set_signature_md() is used. If this function is called for
228       PKCS#1 padding the plaintext buffer is an actual digest value and is
229       encapsulated in a DigestInfo structure according to PKCS#1 when signing
230       and this structure is expected (and stripped off) when verifying. If
231       this control is not used with RSA and PKCS#1 padding then the supplied
232       data is used directly and not encapsulated. In the case of X9.31
233       padding for RSA the algorithm identifier byte is added or checked and
234       removed if this control is called. If it is not called then the first
235       byte of the plaintext buffer is expected to be the algorithm identifier
236       byte.
237
238       EVP_PKEY_CTX_get_rsa_padding() gets the RSA padding mode for ctx.
239
240       EVP_PKEY_CTX_set_rsa_pss_saltlen() sets the RSA PSS salt length to
241       saltlen.  As its name implies it is only supported for PSS padding. If
242       this function is not called then the maximum salt length is used when
243       signing and auto detection when verifying. Three special values are
244       supported:
245
246       RSA_PSS_SALTLEN_DIGEST
247           sets the salt length to the digest length.
248
249       RSA_PSS_SALTLEN_MAX
250           sets the salt length to the maximum permissible value.
251
252       RSA_PSS_SALTLEN_AUTO
253           causes the salt length to be automatically determined based on the
254           PSS block structure when verifying.  When signing, it has the same
255           meaning as RSA_PSS_SALTLEN_MAX.
256
257       EVP_PKEY_CTX_get_rsa_pss_saltlen() gets the RSA PSS salt length for
258       ctx.  The padding mode must already have been set to
259       RSA_PKCS1_PSS_PADDING.
260
261       EVP_PKEY_CTX_set_rsa_keygen_bits() sets the RSA key length for RSA key
262       generation to bits. If not specified 2048 bits is used.
263
264       EVP_PKEY_CTX_set1_rsa_keygen_pubexp() sets the public exponent value
265       for RSA key generation to the value stored in pubexp. Currently it
266       should be an odd integer. In accordance with the OpenSSL naming
267       convention, the pubexp pointer must be freed independently of the
268       EVP_PKEY_CTX (ie, it is internally copied).  If not specified 65537 is
269       used.
270
271       EVP_PKEY_CTX_set_rsa_keygen_pubexp() does the same as
272       EVP_PKEY_CTX_set1_rsa_keygen_pubexp() except that there is no internal
273       copy and therefore pubexp should not be modified or freed after the
274       call.
275
276       EVP_PKEY_CTX_set_rsa_keygen_primes() sets the number of primes for RSA
277       key generation to primes. If not specified 2 is used.
278
279       EVP_PKEY_CTX_set_rsa_mgf1_md_name() sets the MGF1 digest for RSA
280       padding schemes to the digest named mdname. If the RSA algorithm
281       implementation for the selected provider supports it then the digest
282       will be fetched using the properties mdprops. If not explicitly set the
283       signing digest is used. The padding mode must have been set to
284       RSA_PKCS1_OAEP_PADDING or RSA_PKCS1_PSS_PADDING.
285
286       EVP_PKEY_CTX_set_rsa_mgf1_md() does the same as
287       EVP_PKEY_CTX_set_rsa_mgf1_md_name() except that the name of the digest
288       is inferred from the supplied md and it is not possible to specify any
289       properties.
290
291       EVP_PKEY_CTX_get_rsa_mgf1_md_name() gets the name of the MGF1 digest
292       algorithm for ctx. If not explicitly set the signing digest is used.
293       The padding mode must have been set to RSA_PKCS1_OAEP_PADDING or
294       RSA_PKCS1_PSS_PADDING.
295
296       EVP_PKEY_CTX_get_rsa_mgf1_md() does the same as
297       EVP_PKEY_CTX_get_rsa_mgf1_md_name() except that it returns a pointer to
298       an EVP_MD object instead. Note that only known, built-in EVP_MD objects
299       will be returned. The EVP_MD object may be NULL if the digest is not
300       one of these (such as a digest only implemented in a third party
301       provider).
302
303       EVP_PKEY_CTX_set_rsa_oaep_md_name() sets the message digest type used
304       in RSA OAEP to the digest named mdname.  If the RSA algorithm
305       implementation for the selected provider supports it then the digest
306       will be fetched using the properties mdprops. The padding mode must
307       have been set to RSA_PKCS1_OAEP_PADDING.
308
309       EVP_PKEY_CTX_set_rsa_oaep_md() does the same as
310       EVP_PKEY_CTX_set_rsa_oaep_md_name() except that the name of the digest
311       is inferred from the supplied md and it is not possible to specify any
312       properties.
313
314       EVP_PKEY_CTX_get_rsa_oaep_md_name() gets the message digest algorithm
315       name used in RSA OAEP and stores it in the buffer name which is of size
316       namelen. The padding mode must have been set to RSA_PKCS1_OAEP_PADDING.
317       The buffer should be sufficiently large for any expected digest
318       algorithm names or the function will fail.
319
320       EVP_PKEY_CTX_get_rsa_oaep_md() does the same as
321       EVP_PKEY_CTX_get_rsa_oaep_md_name() except that it returns a pointer to
322       an EVP_MD object instead. Note that only known, built-in EVP_MD objects
323       will be returned. The EVP_MD object may be NULL if the digest is not
324       one of these (such as a digest only implemented in a third party
325       provider).
326
327       EVP_PKEY_CTX_set0_rsa_oaep_label() sets the RSA OAEP label to binary
328       data label and its length in bytes to len. If label is NULL or len is
329       0, the label is cleared. The library takes ownership of the label so
330       the caller should not free the original memory pointed to by label.
331       The padding mode must have been set to RSA_PKCS1_OAEP_PADDING.
332
333       EVP_PKEY_CTX_get0_rsa_oaep_label() gets the RSA OAEP label to label.
334       The return value is the label length. The padding mode must have been
335       set to RSA_PKCS1_OAEP_PADDING. The resulting pointer is owned by the
336       library and should not be freed by the caller.
337
338       RSA_PKCS1_WITH_TLS_PADDING is used when decrypting an RSA encrypted TLS
339       pre-master secret in a TLS ClientKeyExchange message. It is the same as
340       RSA_PKCS1_PADDING except that it additionally verifies that the result
341       is the correct length and the first two bytes are the protocol version
342       initially requested by the client. If the encrypted content is publicly
343       invalid then the decryption will fail. However, if the padding checks
344       fail then decryption will still appear to succeed but a random TLS
345       premaster secret will be returned instead. This padding mode accepts
346       two parameters which can be set using the EVP_PKEY_CTX_set_params(3)
347       function. These are OSSL_ASYM_CIPHER_PARAM_TLS_CLIENT_VERSION and
348       OSSL_ASYM_CIPHER_PARAM_TLS_NEGOTIATED_VERSION, both of which are
349       expected to be unsigned integers. Normally only the first of these will
350       be set and represents the TLS protocol version that was first requested
351       by the client (e.g. 0x0303 for TLSv1.2, 0x0302 for TLSv1.1 etc).
352       Historically some buggy clients would use the negotiated protocol
353       version instead of the protocol version first requested. If this
354       behaviour should be tolerated then
355       OSSL_ASYM_CIPHER_PARAM_TLS_NEGOTIATED_VERSION should be set to the
356       actual negotiated protocol version. Otherwise it should be left unset.
357
358       Similarly to the RSA_PKCS1_WITH_TLS_PADDING above, since OpenSSL
359       version 3.1.0, the use of RSA_PKCS1_PADDING will return a randomly
360       generated message instead of padding errors in case padding checks
361       fail. Applications that want to remain secure while using earlier
362       versions of OpenSSL, still need to handle both the error code from the
363       RSA decryption operation and the returned message in a side channel
364       secure manner.  This protection against Bleichenbacher attacks can be
365       disabled by setting the OSSL_ASYM_CIPHER_PARAM_IMPLICIT_REJECTION (an
366       unsigned integer) to 0.
367
368   DSA parameters
369       EVP_PKEY_CTX_set_dsa_paramgen_bits() sets the number of bits used for
370       DSA parameter generation to nbits. If not specified, 2048 is used.
371
372       EVP_PKEY_CTX_set_dsa_paramgen_q_bits() sets the number of bits in the
373       subprime parameter q for DSA parameter generation to qbits. If not
374       specified, 224 is used. If a digest function is specified below, this
375       parameter is ignored and instead, the number of bits in q matches the
376       size of the digest.
377
378       EVP_PKEY_CTX_set_dsa_paramgen_md() sets the digest function used for
379       DSA parameter generation to md. If not specified, one of SHA-1,
380       SHA-224, or SHA-256 is selected to match the bit length of q above.
381
382       EVP_PKEY_CTX_set_dsa_paramgen_md_props() sets the digest function used
383       for DSA parameter generation using md_name and md_properties to
384       retrieve the digest from a provider.  If not specified, md_name will be
385       set to one of SHA-1, SHA-224, or SHA-256 depending on the bit length of
386       q above. md_properties is a property query string that has a default
387       value of '' if not specified.
388
389       EVP_PKEY_CTX_set_dsa_paramgen_gindex() sets the gindex used by the
390       generator G. The default value is -1 which uses unverifiable g,
391       otherwise a positive value uses verifiable g. This value must be saved
392       if key validation of g is required, since it is not part of a persisted
393       key.
394
395       EVP_PKEY_CTX_set_dsa_paramgen_seed() sets the seed to use for
396       generation rather than using a randomly generated value for the seed.
397       This is useful for testing purposes only and can fail if the seed does
398       not produce primes for both p & q on its first iteration. This value
399       must be saved if key validation of p, q, and verifiable g are required,
400       since it is not part of a persisted key.
401
402       EVP_PKEY_CTX_set_dsa_paramgen_type() sets the generation type to use
403       FIPS186-4 generation if name is "fips186_4", or FIPS186-2 generation if
404       name is "fips186_2". The default value for the default provider is
405       "fips186_2". The default value for the FIPS provider is "fips186_4".
406
407   DH parameters
408       EVP_PKEY_CTX_set_dh_paramgen_prime_len() sets the length of the DH
409       prime parameter p for DH parameter generation. If this function is not
410       called then 2048 is used. Only accepts lengths greater than or equal to
411       256.
412
413       EVP_PKEY_CTX_set_dh_paramgen_subprime_len() sets the length of the DH
414       optional subprime parameter q for DH parameter generation. The default
415       is 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".
417
418       EVP_PKEY_CTX_set_dh_paramgen_generator() sets DH generator to gen for
419       DH parameter generation. If not specified 2 is used.
420
421       EVP_PKEY_CTX_set_dh_paramgen_type() sets the key type for DH parameter
422       generation. The supported parameters are:
423
424       DH_PARAMGEN_TYPE_GROUP
425           Use a named group. If only the safe prime parameter p is set this
426           can be used to select a ffdhe safe prime group of the correct size.
427
428       DH_PARAMGEN_TYPE_FIPS_186_4
429           FIPS186-4 FFC parameter generator.
430
431       DH_PARAMGEN_TYPE_FIPS_186_2
432           FIPS186-2 FFC parameter generator (X9.42 DH).
433
434       DH_PARAMGEN_TYPE_GENERATOR
435           Uses a safe prime generator g (PKCS#3 format).
436
437       The default in the default provider is DH_PARAMGEN_TYPE_GENERATOR for
438       the "DH" keytype, and DH_PARAMGEN_TYPE_FIPS_186_2 for the "DHX"
439       keytype. In the FIPS provider the default value is
440       DH_PARAMGEN_TYPE_GROUP for the "DH" keytype and
441       <DH_PARAMGEN_TYPE_FIPS_186_4 for the "DHX" keytype.
442
443       EVP_PKEY_CTX_set_dh_paramgen_gindex() sets the gindex used by the
444       generator G.  The default value is -1 which uses unverifiable g,
445       otherwise a positive value uses verifiable g. This value must be saved
446       if key validation of g is required, since it is not part of a persisted
447       key.
448
449       EVP_PKEY_CTX_set_dh_paramgen_seed() sets the seed to use for generation
450       rather than using a randomly generated value for the seed. This is
451       useful for testing purposes only and can fail if the seed does not
452       produce primes for both p & q on its first iteration. This value must
453       be saved if key validation of p, q, and verifiable g are required,
454       since it is not part of a persisted key.
455
456       EVP_PKEY_CTX_set_dh_pad() sets the DH padding mode.  If pad is 1 the
457       shared secret is padded with zeros up to the size of the DH prime p.
458       If pad is zero (the default) then no padding is performed.
459
460       EVP_PKEY_CTX_set_dh_nid() sets the DH parameters to values
461       corresponding to nid as defined in RFC7919 or RFC3526. The nid
462       parameter must be NID_ffdhe2048, NID_ffdhe3072, NID_ffdhe4096,
463       NID_ffdhe6144, NID_ffdhe8192, NID_modp_1536, NID_modp_2048,
464       NID_modp_3072, NID_modp_4096, NID_modp_6144, NID_modp_8192 or NID_undef
465       to clear the stored value. This function can be called during parameter
466       or key generation.  The nid parameter and the rfc5114 parameter are
467       mutually exclusive.
468
469       EVP_PKEY_CTX_set_dh_rfc5114() and EVP_PKEY_CTX_set_dhx_rfc5114() both
470       set the DH parameters to the values defined in RFC5114. The rfc5114
471       parameter must be 1, 2 or 3 corresponding to RFC5114 sections 2.1, 2.2
472       and 2.3. or 0 to clear the stored value. This macro can be called
473       during parameter generation. The ctx must have a key type of
474       EVP_PKEY_DHX.  The rfc5114 parameter and the nid parameter are mutually
475       exclusive.
476
477   DH key derivation function parameters
478       Note that all of the following functions require that the ctx parameter
479       has a private key type of EVP_PKEY_DHX. When using key derivation, the
480       output of EVP_PKEY_derive() is the output of the KDF instead of the DH
481       shared secret.  The KDF output is typically used as a Key Encryption
482       Key (KEK) that in turn encrypts a Content Encryption Key (CEK).
483
484       EVP_PKEY_CTX_set_dh_kdf_type() sets the key derivation function type to
485       kdf for DH key derivation. Possible values are EVP_PKEY_DH_KDF_NONE and
486       EVP_PKEY_DH_KDF_X9_42 which uses the key derivation specified in
487       RFC2631 (based on the keying algorithm described in X9.42). When using
488       key derivation, the kdf_oid, kdf_md and kdf_outlen parameters must also
489       be specified.
490
491       EVP_PKEY_CTX_get_dh_kdf_type() gets the key derivation function type
492       for ctx used for DH key derivation. Possible values are
493       EVP_PKEY_DH_KDF_NONE and EVP_PKEY_DH_KDF_X9_42.
494
495       EVP_PKEY_CTX_set0_dh_kdf_oid() sets the key derivation function object
496       identifier to oid for DH key derivation. This OID should identify the
497       algorithm to be used with the Content Encryption Key.  The library
498       takes ownership of the object identifier so the caller should not free
499       the original memory pointed to by oid.
500
501       EVP_PKEY_CTX_get0_dh_kdf_oid() gets the key derivation function oid for
502       ctx used for DH key derivation. The resulting pointer is owned by the
503       library and should not be freed by the caller.
504
505       EVP_PKEY_CTX_set_dh_kdf_md() sets the key derivation function message
506       digest to md for DH key derivation. Note that RFC2631 specifies that
507       this digest should be SHA1 but OpenSSL tolerates other digests.
508
509       EVP_PKEY_CTX_get_dh_kdf_md() gets the key derivation function message
510       digest for ctx used for DH key derivation.
511
512       EVP_PKEY_CTX_set_dh_kdf_outlen() sets the key derivation function
513       output length to len for DH key derivation.
514
515       EVP_PKEY_CTX_get_dh_kdf_outlen() gets the key derivation function
516       output length for ctx used for DH key derivation.
517
518       EVP_PKEY_CTX_set0_dh_kdf_ukm() sets the user key material to ukm and
519       its length to len for DH key derivation. This parameter is optional and
520       corresponds to the partyAInfo field in RFC2631 terms. The specification
521       requires that it is 512 bits long but this is not enforced by OpenSSL.
522       The library takes ownership of the user key material so the caller
523       should not free the original memory pointed to by ukm.
524
525       EVP_PKEY_CTX_get0_dh_kdf_ukm() gets the user key material for ctx.  The
526       return value is the user key material length. The resulting pointer is
527       owned by the library and should not be freed by the caller.
528
529   EC parameters
530       Use EVP_PKEY_CTX_set_group_name() (described above) to set the curve
531       name to name for parameter and key generation.
532
533       EVP_PKEY_CTX_set_ec_paramgen_curve_nid() does the same as
534       EVP_PKEY_CTX_set_group_name(), but is specific to EC and uses a nid
535       rather than a name string.
536
537       For EC parameter generation, one of EVP_PKEY_CTX_set_group_name() or
538       EVP_PKEY_CTX_set_ec_paramgen_curve_nid() must be called or an error
539       occurs because there is no default curve.  These function can also be
540       called to set the curve explicitly when generating an EC key.
541
542       EVP_PKEY_CTX_get_group_name() (described above) can be used to obtain
543       the curve name that's currently set with ctx.
544
545       EVP_PKEY_CTX_set_ec_param_enc() sets the EC parameter encoding to
546       param_enc when generating EC parameters or an EC key. The encoding can
547       be OPENSSL_EC_EXPLICIT_CURVE for explicit parameters (the default in
548       versions of OpenSSL before 1.1.0) or OPENSSL_EC_NAMED_CURVE to use
549       named curve form.  For maximum compatibility the named curve form
550       should be used. Note: the OPENSSL_EC_NAMED_CURVE value was added in
551       OpenSSL 1.1.0; previous versions should use 0 instead.
552
553   ECDH parameters
554       EVP_PKEY_CTX_set_ecdh_cofactor_mode() sets the cofactor mode to
555       cofactor_mode for ECDH key derivation. Possible values are 1 to enable
556       cofactor key derivation, 0 to disable it and -1 to clear the stored
557       cofactor mode and fallback to the private key cofactor mode.
558
559       EVP_PKEY_CTX_get_ecdh_cofactor_mode() returns the cofactor mode for ctx
560       used for ECDH key derivation. Possible values are 1 when cofactor key
561       derivation is enabled and 0 otherwise.
562
563   ECDH key derivation function parameters
564       EVP_PKEY_CTX_set_ecdh_kdf_type() sets the key derivation function type
565       to kdf for ECDH key derivation. Possible values are
566       EVP_PKEY_ECDH_KDF_NONE and EVP_PKEY_ECDH_KDF_X9_63 which uses the key
567       derivation specified in X9.63.  When using key derivation, the kdf_md
568       and kdf_outlen parameters must also be specified.
569
570       EVP_PKEY_CTX_get_ecdh_kdf_type() returns the key derivation function
571       type for ctx used for ECDH key derivation. Possible values are
572       EVP_PKEY_ECDH_KDF_NONE and EVP_PKEY_ECDH_KDF_X9_63.
573
574       EVP_PKEY_CTX_set_ecdh_kdf_md() sets the key derivation function message
575       digest to md for ECDH key derivation. Note that X9.63 specifies that
576       this digest should be SHA1 but OpenSSL tolerates other digests.
577
578       EVP_PKEY_CTX_get_ecdh_kdf_md() gets the key derivation function message
579       digest for ctx used for ECDH key derivation.
580
581       EVP_PKEY_CTX_set_ecdh_kdf_outlen() sets the key derivation function
582       output length to len for ECDH key derivation.
583
584       EVP_PKEY_CTX_get_ecdh_kdf_outlen() gets the key derivation function
585       output length for ctx used for ECDH key derivation.
586
587       EVP_PKEY_CTX_set0_ecdh_kdf_ukm() sets the user key material to ukm for
588       ECDH key derivation. This parameter is optional and corresponds to the
589       shared info in X9.63 terms. The library takes ownership of the user key
590       material so the caller should not free the original memory pointed to
591       by ukm.
592
593       EVP_PKEY_CTX_get0_ecdh_kdf_ukm() gets the user key material for ctx.
594       The return value is the user key material length. The resulting pointer
595       is owned by the library and should not be freed by the caller.
596
597   Other parameters
598       EVP_PKEY_CTX_set1_id(), EVP_PKEY_CTX_get1_id() and
599       EVP_PKEY_CTX_get1_id_len() are used to manipulate the special
600       identifier field for specific signature algorithms such as SM2. The
601       EVP_PKEY_CTX_set1_id() sets an ID pointed by id with the length id_len
602       to the library. The library takes a copy of the id so that the caller
603       can safely free the original memory pointed to by id.
604       EVP_PKEY_CTX_get1_id_len() returns the length of the ID set via a
605       previous call to EVP_PKEY_CTX_set1_id(). The length is usually used to
606       allocate adequate memory for further calls to EVP_PKEY_CTX_get1_id().
607       EVP_PKEY_CTX_get1_id() returns the previously set ID value to caller in
608       id. The caller should allocate adequate memory space for the id before
609       calling EVP_PKEY_CTX_get1_id().
610
611       EVP_PKEY_CTX_set_kem_op() sets the KEM operation to run. This can be
612       set after EVP_PKEY_encapsulate_init() or EVP_PKEY_decapsulate_init() to
613       select the kem operation. RSA is the only key type that supports
614       encapsulation currently, and as there is no default operation for the
615       RSA type, this function must be called before EVP_PKEY_encapsulate() or
616       EVP_PKEY_decapsulate().
617

RETURN VALUES

619       All other functions described on this page return a positive value for
620       success and 0 or a negative value for failure. In particular a return
621       value of -2 indicates the operation is not supported by the public key
622       algorithm.
623

SEE ALSO

625       EVP_PKEY_CTX_set_params(3), EVP_PKEY_CTX_new(3), EVP_PKEY_encrypt(3),
626       EVP_PKEY_decrypt(3), EVP_PKEY_sign(3), EVP_PKEY_verify(3),
627       EVP_PKEY_verify_recover(3), EVP_PKEY_derive(3), EVP_PKEY_keygen(3)
628       EVP_PKEY_encapsulate(3) EVP_PKEY_decapsulate(3)
629

HISTORY

631       EVP_PKEY_CTX_get_rsa_oaep_md_name(),
632       EVP_PKEY_CTX_get_rsa_mgf1_md_name(),
633       EVP_PKEY_CTX_set_rsa_mgf1_md_name(),
634       EVP_PKEY_CTX_set_rsa_oaep_md_name(),
635       EVP_PKEY_CTX_set_dsa_paramgen_md_props(),
636       EVP_PKEY_CTX_set_dsa_paramgen_gindex(),
637       EVP_PKEY_CTX_set_dsa_paramgen_type(),
638       EVP_PKEY_CTX_set_dsa_paramgen_seed(), EVP_PKEY_CTX_set_group_name() and
639       EVP_PKEY_CTX_get_group_name() were added in OpenSSL 3.0.
640
641       The EVP_PKEY_CTX_set1_id(), EVP_PKEY_CTX_get1_id() and
642       EVP_PKEY_CTX_get1_id_len() macros were added in 1.1.1, other functions
643       were added in OpenSSL 1.0.0.
644
645       In OpenSSL 1.1.1 and below the functions were mostly macros.  From
646       OpenSSL 3.0 they are all functions.
647
648       EVP_PKEY_CTX_set_rsa_keygen_pubexp(), EVP_PKEY_CTX_get0_dh_kdf_ukm(),
649       and EVP_PKEY_CTX_get0_ecdh_kdf_ukm() were deprecated in OpenSSL 3.0.
650
652       Copyright 2006-2021 The OpenSSL Project Authors. All Rights Reserved.
653
654       Licensed under the Apache License 2.0 (the "License").  You may not use
655       this file except in compliance with the License.  You can obtain a copy
656       in the file LICENSE in the source distribution or at
657       <https://www.openssl.org/source/license.html>.
658
659
660
6613.0.9                             2023-07-27          EVP_PKEY_CTX_CTRL(3ossl)
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