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() and
EVP_DecryptFinal()
routines, as documented on the
EVP_EncryptInit(3) manual 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¶
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¶
evp(3),
rand(3),
EVP_EncryptInit(3),
EVP_SealInit(3)
HISTORY¶