EVP_PKEY_CTX_CTRL(3) OpenSSL EVP_PKEY_CTX_CTRL(3)
NAME
EVP_PKEY_CTX_ctrl, EVP_PKEY_CTX_ctrl_str, EVP_PKEY_CTX_ctrl_uint64,
EVP_PKEY_CTX_md, EVP_PKEY_CTX_set_signature_md,
EVP_PKEY_CTX_get_signature_md, EVP_PKEY_CTX_set_mac_key,
EVP_PKEY_CTX_set_rsa_padding, EVP_PKEY_CTX_get_rsa_padding,
EVP_PKEY_CTX_set_rsa_pss_saltlen, EVP_PKEY_CTX_get_rsa_pss_saltlen,
EVP_PKEY_CTX_set_rsa_keygen_bits, EVP_PKEY_CTX_set_rsa_keygen_pubexp,
EVP_PKEY_CTX_set_rsa_keygen_primes, EVP_PKEY_CTX_set_rsa_mgf1_md,
EVP_PKEY_CTX_get_rsa_mgf1_md, EVP_PKEY_CTX_set_rsa_oaep_md,
EVP_PKEY_CTX_get_rsa_oaep_md, EVP_PKEY_CTX_set0_rsa_oaep_label,
EVP_PKEY_CTX_get0_rsa_oaep_label, EVP_PKEY_CTX_set_dsa_paramgen_bits,
EVP_PKEY_CTX_set_dsa_paramgen_q_bits, EVP_PKEY_CTX_set_dsa_paramgen_md,
EVP_PKEY_CTX_set_dh_paramgen_prime_len,
EVP_PKEY_CTX_set_dh_paramgen_subprime_len,
EVP_PKEY_CTX_set_dh_paramgen_generator,
EVP_PKEY_CTX_set_dh_paramgen_type, EVP_PKEY_CTX_set_dh_rfc5114,
EVP_PKEY_CTX_set_dhx_rfc5114, EVP_PKEY_CTX_set_dh_pad,
EVP_PKEY_CTX_set_dh_nid, EVP_PKEY_CTX_set_dh_kdf_type,
EVP_PKEY_CTX_get_dh_kdf_type, EVP_PKEY_CTX_set0_dh_kdf_oid,
EVP_PKEY_CTX_get0_dh_kdf_oid, EVP_PKEY_CTX_set_dh_kdf_md,
EVP_PKEY_CTX_get_dh_kdf_md, EVP_PKEY_CTX_set_dh_kdf_outlen,
EVP_PKEY_CTX_get_dh_kdf_outlen, EVP_PKEY_CTX_set0_dh_kdf_ukm,
EVP_PKEY_CTX_get0_dh_kdf_ukm, EVP_PKEY_CTX_set_ec_paramgen_curve_nid,
EVP_PKEY_CTX_set_ec_param_enc, EVP_PKEY_CTX_set_ecdh_cofactor_mode,
EVP_PKEY_CTX_get_ecdh_cofactor_mode, EVP_PKEY_CTX_set_ecdh_kdf_type,
EVP_PKEY_CTX_get_ecdh_kdf_type, EVP_PKEY_CTX_set_ecdh_kdf_md,
EVP_PKEY_CTX_get_ecdh_kdf_md, EVP_PKEY_CTX_set_ecdh_kdf_outlen,
EVP_PKEY_CTX_get_ecdh_kdf_outlen, EVP_PKEY_CTX_set0_ecdh_kdf_ukm,
EVP_PKEY_CTX_get0_ecdh_kdf_ukm, EVP_PKEY_CTX_set1_id,
EVP_PKEY_CTX_get1_id, EVP_PKEY_CTX_get1_id_len - 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_uint64(EVP_PKEY_CTX *ctx, int keytype, int optype,
int cmd, uint64_t value);
int EVP_PKEY_CTX_ctrl_str(EVP_PKEY_CTX *ctx, const char *type,
const char *value);
int EVP_PKEY_CTX_md(EVP_PKEY_CTX *ctx, int optype, int cmd, const char *md);
int EVP_PKEY_CTX_set_signature_md(EVP_PKEY_CTX *ctx, const EVP_MD *md);
int EVP_PKEY_CTX_get_signature_md(EVP_PKEY_CTX *ctx, const EVP_MD **pmd);
int EVP_PKEY_CTX_set_mac_key(EVP_PKEY_CTX *ctx, unsigned char *key, int len);
#include <openssl/rsa.h>
int EVP_PKEY_CTX_set_rsa_padding(EVP_PKEY_CTX *ctx, int pad);
int EVP_PKEY_CTX_get_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_get_rsa_pss_saltlen(EVP_PKEY_CTX *ctx, int *len);
int EVP_PKEY_CTX_set_rsa_keygen_bits(EVP_PKEY_CTX *ctx, int mbits);
int EVP_PKEY_CTX_set_rsa_keygen_pubexp(EVP_PKEY_CTX *ctx, BIGNUM *pubexp);
int EVP_PKEY_CTX_set_rsa_keygen_primes(EVP_PKEY_CTX *ctx, int primes);
int EVP_PKEY_CTX_set_rsa_mgf1_md(EVP_PKEY_CTX *ctx, const EVP_MD *md);
int EVP_PKEY_CTX_get_rsa_mgf1_md(EVP_PKEY_CTX *ctx, const EVP_MD **md);
int EVP_PKEY_CTX_set_rsa_oaep_md(EVP_PKEY_CTX *ctx, const EVP_MD *md);
int EVP_PKEY_CTX_get_rsa_oaep_md(EVP_PKEY_CTX *ctx, const EVP_MD **md);
int EVP_PKEY_CTX_set0_rsa_oaep_label(EVP_PKEY_CTX *ctx, unsigned char *label, int len);
int EVP_PKEY_CTX_get0_rsa_oaep_label(EVP_PKEY_CTX *ctx, unsigned char **label);
#include <openssl/dsa.h>
int EVP_PKEY_CTX_set_dsa_paramgen_bits(EVP_PKEY_CTX *ctx, int nbits);
int EVP_PKEY_CTX_set_dsa_paramgen_q_bits(EVP_PKEY_CTX *ctx, int qbits);
int EVP_PKEY_CTX_set_dsa_paramgen_md(EVP_PKEY_CTX *ctx, const EVP_MD *md);
#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_subprime_len(EVP_PKEY_CTX *ctx, int len);
int EVP_PKEY_CTX_set_dh_paramgen_generator(EVP_PKEY_CTX *ctx, int gen);
int EVP_PKEY_CTX_set_dh_paramgen_type(EVP_PKEY_CTX *ctx, int type);
int EVP_PKEY_CTX_set_dh_pad(EVP_PKEY_CTX *ctx, int pad);
int EVP_PKEY_CTX_set_dh_nid(EVP_PKEY_CTX *ctx, int nid);
int EVP_PKEY_CTX_set_dh_rfc5114(EVP_PKEY_CTX *ctx, int rfc5114);
int EVP_PKEY_CTX_set_dhx_rfc5114(EVP_PKEY_CTX *ctx, int rfc5114);
int EVP_PKEY_CTX_set_dh_kdf_type(EVP_PKEY_CTX *ctx, int kdf);
int EVP_PKEY_CTX_get_dh_kdf_type(EVP_PKEY_CTX *ctx);
int EVP_PKEY_CTX_set0_dh_kdf_oid(EVP_PKEY_CTX *ctx, ASN1_OBJECT *oid);
int EVP_PKEY_CTX_get0_dh_kdf_oid(EVP_PKEY_CTX *ctx, ASN1_OBJECT **oid);
int EVP_PKEY_CTX_set_dh_kdf_md(EVP_PKEY_CTX *ctx, const EVP_MD *md);
int EVP_PKEY_CTX_get_dh_kdf_md(EVP_PKEY_CTX *ctx, const EVP_MD **md);
int EVP_PKEY_CTX_set_dh_kdf_outlen(EVP_PKEY_CTX *ctx, int len);
int EVP_PKEY_CTX_get_dh_kdf_outlen(EVP_PKEY_CTX *ctx, int *len);
int EVP_PKEY_CTX_set0_dh_kdf_ukm(EVP_PKEY_CTX *ctx, unsigned char *ukm, int len);
int EVP_PKEY_CTX_get0_dh_kdf_ukm(EVP_PKEY_CTX *ctx, unsigned char **ukm);
#include <openssl/ec.h>
int EVP_PKEY_CTX_set_ec_paramgen_curve_nid(EVP_PKEY_CTX *ctx, int nid);
int EVP_PKEY_CTX_set_ec_param_enc(EVP_PKEY_CTX *ctx, int param_enc);
int EVP_PKEY_CTX_set_ecdh_cofactor_mode(EVP_PKEY_CTX *ctx, int cofactor_mode);
int EVP_PKEY_CTX_get_ecdh_cofactor_mode(EVP_PKEY_CTX *ctx);
int EVP_PKEY_CTX_set_ecdh_kdf_type(EVP_PKEY_CTX *ctx, int kdf);
int EVP_PKEY_CTX_get_ecdh_kdf_type(EVP_PKEY_CTX *ctx);
int EVP_PKEY_CTX_set_ecdh_kdf_md(EVP_PKEY_CTX *ctx, const EVP_MD *md);
int EVP_PKEY_CTX_get_ecdh_kdf_md(EVP_PKEY_CTX *ctx, const EVP_MD **md);
int EVP_PKEY_CTX_set_ecdh_kdf_outlen(EVP_PKEY_CTX *ctx, int len);
int EVP_PKEY_CTX_get_ecdh_kdf_outlen(EVP_PKEY_CTX *ctx, int *len);
int EVP_PKEY_CTX_set0_ecdh_kdf_ukm(EVP_PKEY_CTX *ctx, unsigned char *ukm, int len);
int EVP_PKEY_CTX_get0_ecdh_kdf_ukm(EVP_PKEY_CTX *ctx, unsigned char **ukm);
int EVP_PKEY_CTX_set1_id(EVP_PKEY_CTX *ctx, void *id, size_t id_len);
int EVP_PKEY_CTX_get1_id(EVP_PKEY_CTX *ctx, void *id);
int EVP_PKEY_CTX_get1_id_len(EVP_PKEY_CTX *ctx, size_t *id_len);
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.
For cmd = EVP_PKEY_CTRL_SET_MAC_KEY, p1 is the length of the MAC key,
and p2 is MAC key. This is used by Poly1305, SipHash, HMAC and CMAC.
Applications will not normally call EVP_PKEY_CTX_ctrl() directly but
will instead call one of the algorithm specific macros below.
The function EVP_PKEY_CTX_ctrl_uint64() is a wrapper that directly
passes a uint64 value as p2 to EVP_PKEY_CTX_ctrl().
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.
The function EVP_PKEY_CTX_md() sends a message digest control operation
to the context ctx. The message digest is specified by its name md.
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 in the RSA, DSA and ECDSA
algorithms.
The EVP_PKEY_CTX_get_signature_md() macro gets the message digest type
used in a signature. It can be used in the RSA, DSA and ECDSA
algorithms.
Key generation typically involves setting up parameters to be used and
generating the private and public key data. Some algorithm
implementations allow private key data to be set explicitly using the
EVP_PKEY_CTX_set_mac_key() macro. In this case key generation is simply
the process of setting up the parameters for the key and then setting
the raw key data to the value explicitly provided by that macro.
Normally applications would call EVP_PKEY_new_raw_private_key(3) or
similar functions instead of this macro.
The EVP_PKEY_CTX_set_mac_key() macro can be used with any of the
algorithms supported by the EVP_PKEY_new_raw_private_key(3) function.
RSA parameters
The EVP_PKEY_CTX_set_rsa_padding() macro 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_get_rsa_padding() macro gets the RSA padding mode for
ctx.
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. Three special values are supported: RSA_PSS_SALTLEN_DIGEST
sets the salt length to the digest length, RSA_PSS_SALTLEN_MAX sets the
salt length to the maximum permissible value. When verifying
RSA_PSS_SALTLEN_AUTO causes the salt length to be automatically
determined based on the PSS block structure. If this macro is not
called maximum salt length is used when signing and auto detection when
verifying is used by default.
The EVP_PKEY_CTX_get_rsa_pss_saltlen() macro gets the RSA PSS salt
length for ctx. The padding mode must have been set to
RSA_PKCS1_PSS_PADDING.
The EVP_PKEY_CTX_set_rsa_keygen_bits() macro sets the RSA key length
for RSA key generation to bits. If not specified 1024 bits is used.
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 freed after the call. If not specified 65537
is used.
The EVP_PKEY_CTX_set_rsa_keygen_primes() macro sets the number of
primes for RSA key generation to primes. If not specified 2 is used.
The EVP_PKEY_CTX_set_rsa_mgf1_md() macro sets the MGF1 digest for RSA
padding schemes to md. If not explicitly set the signing digest is
used. The padding mode must have been set to RSA_PKCS1_OAEP_PADDING or
RSA_PKCS1_PSS_PADDING.
The EVP_PKEY_CTX_get_rsa_mgf1_md() macro gets the MGF1 digest for ctx.
If not explicitly set the signing digest is used. The padding mode must
have been set to RSA_PKCS1_OAEP_PADDING or RSA_PKCS1_PSS_PADDING.
The EVP_PKEY_CTX_set_rsa_oaep_md() macro sets the message digest type
used in RSA OAEP to md. The padding mode must have been set to
RSA_PKCS1_OAEP_PADDING.
The EVP_PKEY_CTX_get_rsa_oaep_md() macro gets the message digest type
used in RSA OAEP to md. The padding mode must have been set to
RSA_PKCS1_OAEP_PADDING.
The EVP_PKEY_CTX_set0_rsa_oaep_label() macro sets the RSA OAEP label to
label and its length to len. If label is NULL or len is 0, the label is
cleared. The library takes ownership of the label so the caller should
not free the original memory pointed to by label. The padding mode
must have been set to RSA_PKCS1_OAEP_PADDING.
The EVP_PKEY_CTX_get0_rsa_oaep_label() macro gets the RSA OAEP label to
label. The return value is the label length. The padding mode must have
been set to RSA_PKCS1_OAEP_PADDING. The resulting pointer is owned by
the library and should not be freed by the caller.
Similarly to the RSA_PKCS1_WITH_TLS_PADDING above, since OpenSSL
version 3.1.0, the use of RSA_PKCS1_PADDING will return a randomly
generated message instead of padding errors in case padding checks
fail. Applications that want to remain secure while using earlier
versions of OpenSSL, still need to handle both the error code from the
RSA decryption operation and the returned message in a side channel
secure manner. This protection against Bleichenbacher attacks can be
disabled by setting the OSSL_ASYM_CIPHER_PARAM_IMPLICIT_REJECTION (an
unsigned integer) to 0.
DSA parameters
The EVP_PKEY_CTX_set_dsa_paramgen_bits() macro sets the number of bits
used for DSA parameter generation to nbits. If not specified, 1024 is
used.
The EVP_PKEY_CTX_set_dsa_paramgen_q_bits() macro sets the number of
bits in the subprime parameter q for DSA parameter generation to qbits.
If not specified, 160 is used. If a digest function is specified below,
this parameter is ignored and instead, the number of bits in q matches
the size of the digest.
The EVP_PKEY_CTX_set_dsa_paramgen_md() macro sets the digest function
used for DSA parameter generation to md. If not specified, one of
SHA-1, SHA-224, or SHA-256 is selected to match the bit length of q
above.
DH parameters
The EVP_PKEY_CTX_set_dh_paramgen_prime_len() macro sets the length of
the DH prime parameter p for DH parameter generation. If this macro is
not called then 1024 is used. Only accepts lengths greater than or
equal to 256.
The EVP_PKEY_CTX_set_dh_paramgen_subprime_len() macro sets the length
of the DH optional subprime parameter q for DH parameter generation.
The default is 256 if the prime is at least 2048 bits long or 160
otherwise. The DH paramgen type must have been set to x9.42.
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_dh_paramgen_type() macro sets the key type for DH
parameter generation. Use 0 for PKCS#3 DH and 1 for X9.42 DH. The
default is 0.
The EVP_PKEY_CTX_set_dh_pad() macro sets the DH padding mode. If pad is
1 the shared secret is padded with zeros up to the size of the DH prime
p. If pad is zero (the default) then no padding is performed.
EVP_PKEY_CTX_set_dh_nid() sets the DH parameters to values
corresponding to nid as defined in RFC7919 or RFC3526. The nid
parameter must be NID_ffdhe2048, NID_ffdhe3072, NID_ffdhe4096,
NID_ffdhe6144, NID_ffdhe8192, NID_modp_1536, NID_modp_2048,
NID_modp_3072, NID_modp_4096, NID_modp_6144, NID_modp_8192 or NID_undef
to clear the stored value. This macro can be called during parameter or
key generation. The nid parameter and the rfc5114 parameter are
mutually exclusive.
The EVP_PKEY_CTX_set_dh_rfc5114() and EVP_PKEY_CTX_set_dhx_rfc5114()
macros are synonymous. They set the DH parameters to the values defined
in RFC5114. The rfc5114 parameter must be 1, 2 or 3 corresponding to
RFC5114 sections 2.1, 2.2 and 2.3. or 0 to clear the stored value. This
macro can be called during parameter generation. The ctx must have a
key type of EVP_PKEY_DHX. The rfc5114 parameter and the nid parameter
are mutually exclusive.
DH key derivation function parameters
Note that all of the following functions require that the ctx parameter
has a private key type of EVP_PKEY_DHX. When using key derivation, the
output of EVP_PKEY_derive() is the output of the KDF instead of the DH
shared secret. The KDF output is typically used as a Key Encryption
Key (KEK) that in turn encrypts a Content Encryption Key (CEK).
The EVP_PKEY_CTX_set_dh_kdf_type() macro sets the key derivation
function type to kdf for DH key derivation. Possible values are
EVP_PKEY_DH_KDF_NONE and EVP_PKEY_DH_KDF_X9_42 which uses the key
derivation specified in RFC2631 (based on the keying algorithm
described in X9.42). When using key derivation, the kdf_oid, kdf_md and
kdf_outlen parameters must also be specified.
The EVP_PKEY_CTX_get_dh_kdf_type() macro gets the key derivation
function type for ctx used for DH key derivation. Possible values are
EVP_PKEY_DH_KDF_NONE and EVP_PKEY_DH_KDF_X9_42.
The EVP_PKEY_CTX_set0_dh_kdf_oid() macro sets the key derivation
function object identifier to oid for DH key derivation. This OID
should identify the algorithm to be used with the Content Encryption
Key. The library takes ownership of the object identifier so the
caller should not free the original memory pointed to by oid.
The EVP_PKEY_CTX_get0_dh_kdf_oid() macro gets the key derivation
function oid for ctx used for DH key derivation. The resulting pointer
is owned by the library and should not be freed by the caller.
The EVP_PKEY_CTX_set_dh_kdf_md() macro sets the key derivation function
message digest to md for DH key derivation. Note that RFC2631 specifies
that this digest should be SHA1 but OpenSSL tolerates other digests.
The EVP_PKEY_CTX_get_dh_kdf_md() macro gets the key derivation function
message digest for ctx used for DH key derivation.
The EVP_PKEY_CTX_set_dh_kdf_outlen() macro sets the key derivation
function output length to len for DH key derivation.
The EVP_PKEY_CTX_get_dh_kdf_outlen() macro gets the key derivation
function output length for ctx used for DH key derivation.
The EVP_PKEY_CTX_set0_dh_kdf_ukm() macro sets the user key material to
ukm and its length to len for DH key derivation. This parameter is
optional and corresponds to the partyAInfo field in RFC2631 terms. The
specification requires that it is 512 bits long but this is not
enforced by OpenSSL. The library takes ownership of the user key
material so the caller should not free the original memory pointed to
by ukm.
The EVP_PKEY_CTX_get0_dh_kdf_ukm() macro gets the user key material for
ctx. The return value is the user key material length. The resulting
pointer is owned by the library and should not be freed by the caller.
EC parameters
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.
This function can also be called to set the curve explicitly when
generating an EC key.
The EVP_PKEY_CTX_set_ec_param_enc() macro sets the EC parameter
encoding to param_enc when generating EC parameters or an EC key. The
encoding can be OPENSSL_EC_EXPLICIT_CURVE for explicit parameters (the
default in versions of OpenSSL before 1.1.0) or OPENSSL_EC_NAMED_CURVE
to use named curve form. For maximum compatibility the named curve
form should be used. Note: the OPENSSL_EC_NAMED_CURVE value was added
in OpenSSL 1.1.0; previous versions should use 0 instead.
ECDH parameters
The EVP_PKEY_CTX_set_ecdh_cofactor_mode() macro sets the cofactor mode
to cofactor_mode for ECDH key derivation. Possible values are 1 to
enable cofactor key derivation, 0 to disable it and -1 to clear the
stored cofactor mode and fallback to the private key cofactor mode.
The EVP_PKEY_CTX_get_ecdh_cofactor_mode() macro returns the cofactor
mode for ctx used for ECDH key derivation. Possible values are 1 when
cofactor key derivation is enabled and 0 otherwise.
ECDH key derivation function parameters
The EVP_PKEY_CTX_set_ecdh_kdf_type() macro sets the key derivation
function type to kdf for ECDH key derivation. Possible values are
EVP_PKEY_ECDH_KDF_NONE and EVP_PKEY_ECDH_KDF_X9_63 which uses the key
derivation specified in X9.63. When using key derivation, the kdf_md
and kdf_outlen parameters must also be specified.
The EVP_PKEY_CTX_get_ecdh_kdf_type() macro returns the key derivation
function type for ctx used for ECDH key derivation. Possible values are
EVP_PKEY_ECDH_KDF_NONE and EVP_PKEY_ECDH_KDF_X9_63.
The EVP_PKEY_CTX_set_ecdh_kdf_md() macro sets the key derivation
function message digest to md for ECDH key derivation. Note that X9.63
specifies that this digest should be SHA1 but OpenSSL tolerates other
digests.
The EVP_PKEY_CTX_get_ecdh_kdf_md() macro gets the key derivation
function message digest for ctx used for ECDH key derivation.
The EVP_PKEY_CTX_set_ecdh_kdf_outlen() macro sets the key derivation
function output length to len for ECDH key derivation.
The EVP_PKEY_CTX_get_ecdh_kdf_outlen() macro gets the key derivation
function output length for ctx used for ECDH key derivation.
The EVP_PKEY_CTX_set0_ecdh_kdf_ukm() macro sets the user key material
to ukm for ECDH key derivation. This parameter is optional and
corresponds to the shared info in X9.63 terms. The library takes
ownership of the user key material so the caller should not free the
original memory pointed to by ukm.
The EVP_PKEY_CTX_get0_ecdh_kdf_ukm() macro gets the user key material
for ctx. The return value is the user key material length. The
resulting pointer is owned by the library and should not be freed by
the caller.
Other parameters
The EVP_PKEY_CTX_set1_id(), EVP_PKEY_CTX_get1_id() and
EVP_PKEY_CTX_get1_id_len() macros are used to manipulate the special
identifier field for specific signature algorithms such as SM2. The
EVP_PKEY_CTX_set1_id() sets an ID pointed by id with the length id_len
to the library. The library takes a copy of the id so that the caller
can safely free the original memory pointed to by id. The
EVP_PKEY_CTX_get1_id_len() macro returns the length of the ID set via a
previous call to EVP_PKEY_CTX_set1_id(). The length is usually used to
allocate adequate memory for further calls to EVP_PKEY_CTX_get1_id().
The EVP_PKEY_CTX_get1_id() macro returns the previously set ID value to
caller in id. The caller should allocate adequate memory space for the
id before calling EVP_PKEY_CTX_get1_id().
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
The EVP_PKEY_CTX_set1_id(), EVP_PKEY_CTX_get1_id() and
EVP_PKEY_CTX_get1_id_len() macros were added in 1.1.1, other functions
were added in OpenSSL 1.0.0.
COPYRIGHT
Copyright 2006-2020 The OpenSSL Project Authors. All Rights Reserved.
Licensed under the OpenSSL license (the "License"). You may not use
this file except in compliance with the License. You can obtain a copy
in the file LICENSE in the source distribution or at
<https://www.openssl.org/source/license.html>;.
1.1.1k 2024-10-09 EVP_PKEY_CTX_CTRL(3)
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