EVP_OpenInit(3)EVP_OpenInit(3)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.
The EVP_OpenInit() function 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.
The EVP_OpenUpdate() and EVP_OpenFinal() functions have the same prop‐
erties as the EVP_DecryptUpdate() and EVP_DecryptFinal() functions, as
documented on the
EVP_EncryptInit(3) reference page.
NOTES
It is possible to call EVP_OpenInit() twice in the same way as
EVP_DecryptInit(). 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.
RETURN VALUES
The EVP_OpenInit() function returns 0 on error or a nonzero integer
(actually the recovered secret key size) if successful.
The EVP_OpenUpdate() function returns 1 for success or 0 for failure.
The EVP_OpenFinal() function returns 0 if the decrypt failed or 1 for
success.
SEE ALSO
Functions: evp(3), rand_ssl(3), EVP_EncryptInit(3), EVP_SealInit(3)EVP_OpenInit(3)