NAME
EVP_OpenInit,
EVP_OpenUpdate,
EVP_OpenFinal —
EVP envelope decryption
SYNOPSIS
#include
<openssl/evp.h>
int
EVP_OpenInit(EVP_CIPHER_CTX
*ctx, EVP_CIPHER *type, unsigned
char *ek, int ekl, unsigned char
*iv, EVP_PKEY *priv);
int
EVP_OpenUpdate(EVP_CIPHER_CTX
*ctx, unsigned char *out, int
*outl, unsigned char *in, int
inl);
int
EVP_OpenFinal(EVP_CIPHER_CTX
*ctx, unsigned char *out, int
*outl);
DESCRIPTION
The EVP envelope routines are a high level interface to envelope decryption. They decrypt a public key encrypted symmetric key and then decrypt data using it.
EVP_OpenInit()
initializes a cipher context ctx for decryption with
cipher type. It decrypts the encrypted symmetric key
of length ekl bytes passed in the
ek parameter using the private key
priv. The IV is supplied in the
iv parameter.
EVP_OpenUpdate()
and
EVP_OpenFinal()
have exactly the same properties as the
EVP_DecryptUpdate(3) and
EVP_DecryptFinal(3) routines.
It is possible to call
EVP_OpenInit()
twice in the same way as
EVP_DecryptInit(3). The first call should have
priv set to NULL and (after
setting any cipher parameters) it should be called again with
type set to NULL.
If the cipher passed in the type parameter is a variable length cipher then the key length will be set to the value of the recovered key length. If the cipher is a fixed length cipher then the recovered key length must match the fixed cipher length.
EVP_OpenUpdate()
is implemented as a macro.
RETURN VALUES
EVP_OpenInit() returns 0 on error or a
non-zero integer (actually the recovered secret key size) if successful.
EVP_OpenUpdate() returns 1 for success or
0 for failure.
EVP_OpenFinal() returns 0 if the decrypt
failed or 1 for success.
SEE ALSO
HISTORY
EVP_OpenInit(),
EVP_OpenUpdate(), and
EVP_OpenFinal() first appeared in SSLeay 0.5.1 and
have been available since OpenBSD 2.4.