NAME¶
shishi_decrypt_ivupdate - API function
SYNOPSIS¶
#include <shishi.h>
int shishi_decrypt_ivupdate(Shishi * handle, Shishi_key *
key, int keyusage, 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.
- 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 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.