NAME

       shishi_decrypt_etype - API function

SYNOPSIS

       #include <shishi.h>

       int  shishi_decrypt_etype(Shishi  * handle, Shishi_key * key, int keyusage, int32_t etype,
       const char * in, size_t inlen, char ** out, size_t * outlen);

ARGUMENTS

       Shishi * handle
                   shishi handle as allocated by shishi_init().

       Shishi_key * key
                   key to decrypt with.

       int keyusage
                   integer specifying what this key is decrypting.

       int32_t etype
                   integer specifying what cipher to use.

       const char * in
                   input array with data to decrypt.

       size_t inlen
                   size of input array with data to decrypt.

       char ** out output array with newly allocated decrypted data.

       size_t * outlen
                   output variable with size of newly allocated output array.

DESCRIPTION

       Decrypts data as per encryption method using specified key.   The  key  actually  used  is
       derived  using  the  key  usage.   If  key usage is 0, no key derivation is used.  The OUT
       buffer  must  be  deallocated  by   the   caller.    The   default   IV   is   used,   see
       shishi_decrypt_iv_etype   if   you   need   to  alter  it.   The  next  IV  is  lost,  see
       shishi_decrypt_ivupdate_etype if you need it.

       Note that DECRYPT(ENCRYPT(data)) does not necessarily yield data exactly.  Some encryption
       types  add  pad  to  make  the  data  fit into the block size of the encryption algorithm.
       Furthermore, the pad is not guaranteed to look  in  any  special  way,  although  existing
       implementations  often  pad  with  the zero byte.  This means that you may have to "frame"
       data, so it is possible to infer the original length after decryption.  Compare ASN.1  DER
       which contains such information.

RETURN VALUE

       Returns SHISHI_OK iff successful.

REPORTING BUGS

       Report      bugs      to      <bug-shishi@gnu.org>.      GNU     Shishi     home     page:
       http://www.gnu.org/software/shishi/     General     help     using      GNU      software:
       http://www.gnu.org/gethelp/

COPYRIGHT

       Copyright © 2002-2022 Simon Josefsson.
       Copying  and distribution of this file, with or without modification, are permitted in any
       medium without royalty provided the copyright notice and this notice are preserved.

SEE ALSO

       The full documentation for shishi is maintained as a Texinfo  manual.   If  the  info  and
       shishi programs are properly installed at your site, the command

              info shishi

       should give you access to the complete manual.