EVPOpenInit(3) OpenSSL EVPOpenInit(3)

NAME
       EVPOpenInit, EVPOpenUpdate, EVPOpenFinal - EVP envelope decryption

SYNOPSIS
        #include 

        int EVPOpenInit(EVPCIPHERCTX *ctx,EVPCIPHER *type,unsigned char *ek,
                       int ekl,unsigned char *iv,EVPPKEY *priv);
        int EVPOpenUpdate(EVPCIPHERCTX *ctx, unsigned char *out,
                int *outl, unsigned char *in, int inl);
        int EVPOpenFinal(EVPCIPHERCTX *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.

       EVPOpenInit() initializes a cipher context ccttxx for decryption with
       cipher ttyyppee. It decrypts the encrypted symmetric key of length eekkll
       bytes passed in the eekk parameter using the private key pprriivv.  The IV is
       supplied in the iivv parameter.

       EVPOpenUpdate() and EVPOpenFinal() have exactly the same properties
       as the EVPDecryptUpdate() and EVPDecryptFinal() routines, as
       documented on the EVPEncryptInit(3) manual page.

NNOOTTEESS
       It is possible to call EVPOpenInit() twice in the same way as
       EVPDecryptInit(). The first call should have pprriivv set to NULL and
       (after setting any cipher parameters) it should be called again with
       ttyyppee set to NULL.

       If the cipher passed in the ttyyppee 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
       EVPOpenInit() returns 0 on error or a non zero integer (actually the
       recovered secret key size) if successful.

       EVPOpenUpdate() returns 1 for success or 0 for failure.

       EVPOpenFinal() returns 0 if the decrypt failed or 1 for success.

SEE ALSO
       evp(3), rand(3), EVPEncryptInit(3), EVPSealInit(3)

HISTORY
0.9.7l                            2000-09-23                   EVPOpenInit(3)