NAME    [Toc]    [Back]

       EVP_OpenInit, EVP_OpenUpdate, EVP_OpenFinal - EVP envelope
       decryption

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.

       The EVP_OpenInit() function 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.

       The EVP_OpenUpdate() and  EVP_OpenFinal()  functions  have
       the   same   properties  as  the  EVP_DecryptUpdate()  and
       EVP_DecryptFinal() functions, as  documented on the

       EVP_EncryptInit(3) reference 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]

       The  EVP_OpenInit()  function  returns  0  on  error  or a
       nonzero integer (actually the recovered secret  key  size)
       if successful.

       The  EVP_OpenUpdate()  function returns 1 for success or 0
       for failure.

       The EVP_OpenFinal() function  returns  0  if  the  decrypt
       failed or 1 for success.

SEE ALSO    [Toc]    [Back]

       Functions:    evp(3),   rand_ssl(3),   EVP_EncryptInit(3),
       EVP_SealInit(3)



                                                  EVP_OpenInit(3)