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>. 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.