EVP_OpenInit(3)             OpenSSL             EVP_OpenInit(3)





NAME
       EVP_OpenInit, EVP_OpenUpdate, EVP_OpenFinal - EVP enve-
       lope 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 sup-
       plied 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 parame-
       ters) 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
0.9.7c                     2000-09-23           EVP_OpenInit(3)
