EVP_PKEY_CTX_set_dsa_paramgen_bits(3)
EVP_PKEY_CTX_ctrl(3) OpenSSL EVP_PKEY_CTX_ctrl(3)
NAME
EVP_PKEY_CTX_ctrl, EVP_PKEY_CTX_ctrl_str,
EVP_PKEY_get_default_digest_nid,
EVP_PKEY_CTX_set_signature_md, EVP_PKEY_CTX_set_rsa_padding,
EVP_PKEY_CTX_set_rsa_pss_saltlen,
EVP_PKEY_CTX_set_rsa_rsa_keygen_bits,
EVP_PKEY_CTX_set_rsa_keygen_pubexp,
EVP_PKEY_CTX_set_dsa_paramgen_bits,
EVP_PKEY_CTX_set_dh_paramgen_prime_len,
EVP_PKEY_CTX_set_dh_paramgen_generator,
EVP_PKEY_CTX_set_ec_paramgen_curve_nid - algorithm specific
control operations
SYNOPSIS
#include <openssl/evp.h>
int EVP_PKEY_CTX_ctrl(EVP_PKEY_CTX *ctx, int keytype, int optype,
int cmd, int p1, void *p2);
int EVP_PKEY_CTX_ctrl_str(EVP_PKEY_CTX *ctx, const char *type,
const char *value);
int EVP_PKEY_get_default_digest_nid(EVP_PKEY *pkey, int *pnid);
#include <openssl/rsa.h>
int EVP_PKEY_CTX_set_signature_md(EVP_PKEY_CTX *ctx, const EVP_MD *md);
int EVP_PKEY_CTX_set_rsa_padding(EVP_PKEY_CTX *ctx, int pad);
int EVP_PKEY_CTX_set_rsa_pss_saltlen(EVP_PKEY_CTX *ctx, int len);
int EVP_PKEY_CTX_set_rsa_rsa_keygen_bits(EVP_PKEY_CTX *ctx, int mbits);
int EVP_PKEY_CTX_set_rsa_keygen_pubexp(EVP_PKEY_CTX *ctx, BIGNUM *pubexp);
#include <openssl/dsa.h>
int EVP_PKEY_CTX_set_dsa_paramgen_bits(EVP_PKEY_CTX *ctx, int nbits);
#include <openssl/dh.h>
int EVP_PKEY_CTX_set_dh_paramgen_prime_len(EVP_PKEY_CTX *ctx, int len);
int EVP_PKEY_CTX_set_dh_paramgen_generator(EVP_PKEY_CTX *ctx, int gen);
#include <openssl/ec.h>
int EVP_PKEY_CTX_set_ec_paramgen_curve_nid(EVP_PKEY_CTX *ctx, int nid);
DESCRIPTION
The function EVP_PKEY_CTX_ctrl() sends a control operation
to the context ctx. The key type used must match keytype if
it is not -1. The parameter optype is a mask indicating
which operations the control can be applied to. The control
command is indicated in cmd and any additional arguments in
p1 and p2.
Applications will not normally call EVP_PKEY_CTX_ctrl()
directly but will instead call one of the algorithm specific
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EVP_PKEY_CTX_ctrl(3) OpenSSL EVP_PKEY_CTX_ctrl(3)
macros below.
The function EVP_PKEY_CTX_ctrl_str() allows an application
to send an algorithm specific control operation to a context
ctx in string form. This is intended to be used for options
specified on the command line or in text files. The commands
supported are documented in the openssl utility command line
pages for the option -pkeyopt which is supported by the
pkeyutl, genpkey and req commands.
All the remaining "functions" are implemented as macros.
The EVP_PKEY_CTX_set_signature_md() macro sets the message
digest type used in a signature. It can be used with any
public key algorithm supporting signature operations.
The macro EVP_PKEY_CTX_set_rsa_padding() sets the RSA
padding mode for ctx. The pad parameter can take the value
RSA_PKCS1_PADDING for PKCS#1 padding, RSA_SSLV23_PADDING for
SSLv23 padding, RSA_NO_PADDING for no padding,
RSA_PKCS1_OAEP_PADDING for OAEP padding (encrypt and decrypt
only), RSA_X931_PADDING for X9.31 padding (signature
operations only) and RSA_PKCS1_PSS_PADDING (sign and verify
only).
Two RSA padding modes behave differently if
EVP_PKEY_CTX_set_signature_md() is used. If this macro is
called for PKCS#1 padding the plaintext buffer is an actual
digest value and is encapsulated in a DigestInfo structure
according to PKCS#1 when signing and this structure is
expected (and stripped off) when verifying. If this control
is not used with RSA and PKCS#1 padding then the supplied
data is used directly and not encapsulated. In the case of
X9.31 padding for RSA the algorithm identifier byte is added
or checked and removed if this control is called. If it is
not called then the first byte of the plaintext buffer is
expected to be the algorithm identifier byte.
The EVP_PKEY_CTX_set_rsa_pss_saltlen() macro sets the RSA
PSS salt length to len as its name implies it is only
supported for PSS padding. Two special values are
supported: -1 sets the salt length to the digest length.
When signing -2 sets the salt length to the maximum
permissible value. When verifying -2 causes the salt length
to be automatically determined based on the PSS block
structure. If this macro is not called a salt length value
of -2 is used by default.
The EVP_PKEY_CTX_set_rsa_rsa_keygen_bits() macro sets the
RSA key length for RSA key genration to bits. If not
specified 1024 bits is used.
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EVP_PKEY_CTX_ctrl(3) OpenSSL EVP_PKEY_CTX_ctrl(3)
The EVP_PKEY_CTX_set_rsa_keygen_pubexp() macro sets the
public exponent value for RSA key generation to pubexp
currently it should be an odd integer. The pubexp pointer is
used internally by this function so it should not be
modified or free after the call. If this macro is not called
then 65537 is used.
The macro EVP_PKEY_CTX_set_dsa_paramgen_bits() sets the
number of bits used for DSA parameter generation to bits. If
not specified 1024 is used.
The macro EVP_PKEY_CTX_set_dh_paramgen_prime_len() sets the
length of the DH prime parameter p for DH parameter
generation. If this macro is not called then 1024 is used.
The EVP_PKEY_CTX_set_dh_paramgen_generator() macro sets DH
generator to gen for DH parameter generation. If not
specified 2 is used.
The EVP_PKEY_CTX_set_ec_paramgen_curve_nid() sets the EC
curve for EC parameter generation to nid. For EC parameter
generation this macro must be called or an error occurs
because there is no default curve.
RETURN VALUES
EVP_PKEY_CTX_ctrl() and its macros return a positive value
for success and 0 or a negative value for failure. In
particular a return value of -2 indicates the operation is
not supported by the public key algorithm.
SEE ALSO
EVP_PKEY_CTX_new(3), EVP_PKEY_encrypt(3),
EVP_PKEY_decrypt(3), EVP_PKEY_sign(3), EVP_PKEY_verify(3),
EVP_PKEY_verify_recover(3), EVP_PKEY_derive(3)
EVP_PKEY_keygen(3)
HISTORY
These functions were first added to OpenSSL 1.0.0.
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