NAME

       kcapi_cipher_decrypt - decrypt data (synchronous one shot)

SYNOPSIS

       ssize_t kcapi_cipher_decrypt(struct kcapi_handle * handle, const uint8_t * in,
                                    size_t inlen, const uint8_t * iv, uint8_t * out,
                                    size_t outlen, int access);

ARGUMENTS

       handle
           [in] cipher handle

       in
           [in] ciphertext data buffer

       inlen
           [in] length of in buffer

       iv
           [in] IV to be used for cipher operation

       out
           [out] plaintext data buffer

       outlen
           [in] length of out bufferS

       access
           [in] kernel access type (KCAPI_ACCESS_HEURISTIC - use internal heuristic for fastest
           kernel access; KCAPI_ACCESS_VMSPLICE - use vmsplice access; KCAPI_ACCESS_SENDMSG -
           sendmsg access)

DESCRIPTION

       It is perfectly legal to use the same buffer as the plaintext and ciphertext pointers.
       That would mean that after the encryption operation, the ciphertext is overwritten with
       the plaintext.

       The memory should be aligned at the page boundary using
       posix_memalign(sysconf(_SC_PAGESIZE)), If it is not aligned at the page boundary, the
       vmsplice call may not send all data to the kernel.

       The IV buffer must be exactly kcapi_cipher_ivsize bytes in size.

       return number of bytes decrypted upon success; a negative errno-style error code if an
       error occurred

AUTHOR

       Stephan Mueller <smueller@chronox.de>
           Author.

COPYRIGHT