NAME
shishi_decrypt_ivupdate_etype - API function
SYNOPSIS
#include <shishi.h>
int shishi_decrypt_ivupdate_etype(Shishi * handle, Shishi_key * key,
int keyusage, int32_t etype, const char * iv, size_t ivlen, char **
ivout, size_t * ivoutlen, 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 * iv
input array with initialization vector
size_t ivlen
size of input array with initialization vector.
char ** ivout
output array with newly allocated updated initialization
vector.
size_t * ivoutlen
size of output array with updated initialization vector.
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 initialization
vector and 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. If IVOUT or IVOUTLEN is NULL, the updated
IV is not saved anywhere.
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>.
COPYRIGHT
Copyright © 2002-2010 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.