EVP_PKEY_CTX_GET_OPERATION(3)

NAME
EVP_PKEY_CTX_get_operation, EVP_PKEY_CTX_get0_pkey - inspect EVP_PKEY_CTX objects

SYNOPSIS
libcrypto
#include <openssl/evp.h>
int
EVP_PKEY_CTX_get_operation(EVP_PKEY_CTX *ctx);
EVP_PKEY *
EVP_PKEY_CTX_get0_pkey(EVP_PKEY_CTX *ctx);

DESCRIPTION
EVP_PKEY_CTX_get_operation() finds out which initialization function has been called on ctx, if any:
return value | initialized with | e.g. for
EVP_PKEY_OP_DECRYPT | EVP_PKEY_decrypt_init(3) | RSA, SM2
EVP_PKEY_OP_DERIVE | EVP_PKEY_derive_init(3) | HKDF
EVP_PKEY_OP_ENCRYPT | EVP_PKEY_encrypt_init(3) | RSA, SM2
EVP_PKEY_OP_KEYGEN | EVP_PKEY_keygen_init(3) | almost all
EVP_PKEY_OP_PARAMGEN | EVP_PKEY_paramgen_init(3) | DH, DSA, EC
EVP_PKEY_OP_SIGN | EVP_PKEY_sign_init(3) | DSA,EC,RSA,SM2
EVP_PKEY_OP_SIGN | EVP_DigestSignInit(3) | ED25519
EVP_PKEY_OP_SIGNCTX | EVP_DigestSignInit(3) | CMAC, HMAC
EVP_PKEY_OP_UNDEFINED | not initialized | NONE
EVP_PKEY_OP_VERIFY | EVP_PKEY_verify_init(3) | DSA,EC,RSA,SM2
EVP_PKEY_OP_VERIFY | EVP_DigestVerifyInit(3) | ED25519
EVP_PKEY_OP_VERIFYCTX | EVP_DigestVerifyInit(3) | no built-in
EVP_PKEY_OP_VERIFYRECOVER | EVP_PKEY_verify_recover_init(3) | RSA

The rightmost column of the above table shows examples of algorithms the return values can occur for. For example, if EVP_PKEY_base_id(3) returns EVP_PKEY_HKDF, then calling EVP_PKEY_CTX_get_operation() on a EVP_PKEY_CTX using that key may return EVP_PKEY_OP_DERIVE.

If the return value is EVP_PKEY_OP_SIGNCTX or EVP_PKEY_OP_VERIFYCTX, the ctx supports EVP_DigestSignUpdate(3) or EVP_DigestVerifyUpdate(3), respectively. If the return value is EVP_PKEY_OP_SIGN or EVP_PKEY_OP_VERIFY, if does not, and only one-shot signing or verification is supported.

The return value EVP_PKEY_OP_UNDEFINED can for example occur if the ctx was freshly returned from EVP_PKEY_CTX_new(3) or EVP_PKEY_CTX_new_id(3) and not yet initialized.

The following masks are defined as the logical OR of two or more of the above EVP_PKEY_OP_* bits:

EVP_PKEY_OP_TYPE_CRYPT
    DECRYPT | ENCRYPT
EVP_PKEY_OP_TYPE_GEN
    KEYGEN | PARAMGEN
EVP_PKEY_OP_TYPE_NOGEN
    CRYPT | DERIVE | SIG
EVP_PKEY_OP_TYPE_SIG
    SIGN | SIGNCTX | VERIFY | VERIFYCTX | VERIFYRECOVER

RETURN VALUES
EVP_PKEY_CTX_get_operation() returns one of the single-bit EVP_PKEY_OP_* constants or EVP_PKEY_OP_UNDEFINED if ctx is not initialized.

EVP_PKEY_CTX_get0_pkey() returns an internal pointer to the EVP_PKEY object used by ctx, without incrementing its reference count.

SEE ALSO
evp(3), EVP_PKEY_base_id(3), EVP_PKEY_CTX_ctrl(3), EVP_PKEY_CTX_new(3), EVP_PKEY_new(3)

HISTORY
EVP_PKEY_CTX_get_operation() and EVP_PKEY_CTX_get0_pkey() first appeared in OpenSSL 1.0.0 and have been available since OpenBSD 4.9.