NAME    [Toc]    [Back]

       EVP_OpenInit, EVP_OpenUpdate, EVP_OpenFinal - EVP envelope
       decryption

LIBRARY    [Toc]    [Back]

       libcrypto, -lcrypto

SYNOPSIS    [Toc]    [Back]

        #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    [Toc]    [Back]

       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_DecryptFi-
       nal() routines, as documented on the EVP_EncryptInit(3)
       manual page.

NOTES    [Toc]    [Back]

       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    [Toc]    [Back]

       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    [Toc]    [Back]

       openssl_evp(3), openssl_rand(3), EVP_EncryptInit(3),
       EVP_SealInit(3)

HISTORY    [Toc]    [Back]

2001-04-12                    0.9.6g              EVP_OpenInit(3)