EVP_OpenInit(3)

     EVP_OpenInit(3)        0.9.6h (2000-09-23)        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.

          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

     Page 1                                         (printed 1/19/103)

     EVP_OpenInit(3)        0.9.6h (2000-09-23)        EVP_OpenInit(3)

          evp(3), rand(3), EVP_EncryptInit(3), EVP_SealInit(3)

     HISTORY

     Page 2                                         (printed 1/19/103)