.\" $OpenBSD: EVP_PKEY_CTX_get_operation.3,v 1.3 2023/09/12 16:15:23 schwarze Exp $
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.\" Copyright (c) 2023 Ingo Schwarze <schwarze@openbsd.org>
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.Dd $Mdocdate: September 12 2023 $
.Dt EVP_PKEY_CTX_GET_OPERATION 3
.Os
.Sh NAME
.Nm EVP_PKEY_CTX_get_operation ,
.Nm EVP_PKEY_CTX_get0_pkey
.Nd inspect EVP_PKEY_CTX objects
.Sh SYNOPSIS
.In openssl/evp.h
.Ft int
.Fo EVP_PKEY_CTX_get_operation
.Fa "EVP_PKEY_CTX *ctx"
.Fc
.Ft EVP_PKEY *
.Fo EVP_PKEY_CTX_get0_pkey
.Fa "EVP_PKEY_CTX *ctx"
.Fc
.Sh DESCRIPTION
.Fn EVP_PKEY_CTX_get_operation
finds out which initialization function has been called on
.Fa ctx ,
if any:
.Bl -column EVP_PKEY_OP_VERIFYRECO EVP_PKEY_verify_recover_init
.It return value             Ta initialized with            Ta e.g. for
.It Dv EVP_PKEY_OP_DECRYPT   Ta Xr EVP_PKEY_decrypt_init  3 Ta RSA, SM2
.It Dv EVP_PKEY_OP_DERIVE    Ta Xr EVP_PKEY_derive_init   3 Ta HKDF
.It Dv EVP_PKEY_OP_ENCRYPT   Ta Xr EVP_PKEY_encrypt_init  3 Ta RSA, SM2
.It Dv EVP_PKEY_OP_KEYGEN    Ta Xr EVP_PKEY_keygen_init   3 Ta almost all
.It Dv EVP_PKEY_OP_PARAMGEN  Ta Xr EVP_PKEY_paramgen_init 3 Ta DH, DSA, EC
.It Dv EVP_PKEY_OP_SIGN      Ta Xr EVP_PKEY_sign_init     3 Ta DSA,EC,RSA,SM2
.It Dv EVP_PKEY_OP_SIGN      Ta Xr EVP_DigestSignInit     3 Ta ED25519
.It Dv EVP_PKEY_OP_SIGNCTX   Ta Xr EVP_DigestSignInit     3 Ta CMAC, HMAC
.It Dv EVP_PKEY_OP_UNDEFINED Ta not initialized             Ta NONE
.It Dv EVP_PKEY_OP_VERIFY    Ta Xr EVP_PKEY_verify_init   3 Ta DSA,EC,RSA,SM2
.It Dv EVP_PKEY_OP_VERIFY    Ta Xr EVP_DigestVerifyInit   3 Ta ED25519
.It Dv EVP_PKEY_OP_VERIFYCTX Ta Xr EVP_DigestVerifyInit   3 Ta no built-in
.It Dv EVP_PKEY_OP_VERIFYRECOVER Ta Xr EVP_PKEY_verify_recover_init 3 Ta RSA
.El
.Pp
The rightmost column of the above table shows examples of algorithms
the return values can occur for.
For example, if
.Xr EVP_PKEY_base_id 3
returns
.Dv EVP_PKEY_HKDF ,
then calling
.Fn EVP_PKEY_CTX_get_operation
on a
.Vt EVP_PKEY_CTX
using that key may return
.Dv EVP_PKEY_OP_DERIVE .
.Pp
If the return value is
.Dv EVP_PKEY_OP_SIGNCTX
or
.Dv EVP_PKEY_OP_VERIFYCTX ,
the
.Fa ctx
supports
.Xr EVP_DigestSignUpdate 3
or
.Xr EVP_DigestVerifyUpdate 3 ,
respectively.
If the return value is
.Dv EVP_PKEY_OP_SIGN
or
.Dv EVP_PKEY_OP_VERIFY ,
if does not, and only one-shot signing or verification is supported.
.Pp
The return value
.Dv EVP_PKEY_OP_UNDEFINED
can for example occur if the
.Fa ctx
was freshly returned from
.Xr EVP_PKEY_CTX_new 3
or
.Xr EVP_PKEY_CTX_new_id 3
and not yet initialized.
.Pp
The following masks are defined as the logical OR of two or more of the above
.Dv EVP_PKEY_OP_*
bits:
.Pp
.Bl -tag -width EVP_PKEY_OP_TYPE_NOGEN -compact
.It Dv EVP_PKEY_OP_TYPE_CRYPT
DECRYPT | ENCRYPT
.It Dv EVP_PKEY_OP_TYPE_GEN
KEYGEN | PARAMGEN
.It Dv EVP_PKEY_OP_TYPE_NOGEN
CRYPT | DERIVE | SIG
.It Dv EVP_PKEY_OP_TYPE_SIG
SIGN | SIGNCTX | VERIFY | VERIFYCTX | VERIFYRECOVER
.El
.Sh RETURN VALUES
.Fn EVP_PKEY_CTX_get_operation
returns one of the single-bit
.Dv EVP_PKEY_OP_*
constants or
.Dv EVP_PKEY_OP_UNDEFINED
if
.Fa ctx
is not initialized.
.Pp
.Fn EVP_PKEY_CTX_get0_pkey
returns an internal pointer to the
.Vt EVP_PKEY
object used by
.Fa ctx ,
without incrementing its reference count.
.Sh SEE ALSO
.Xr evp 3 ,
.Xr EVP_PKEY_base_id 3 ,
.Xr EVP_PKEY_CTX_ctrl 3 ,
.Xr EVP_PKEY_CTX_new 3 ,
.Xr EVP_PKEY_new 3
.Sh HISTORY
.Fn EVP_PKEY_CTX_get_operation
and
.Fn EVP_PKEY_CTX_get0_pkey
first appeared in OpenSSL 1.0.0 and have been available since
.Ox 4.9 .