I wrote a test program and the output for the mcrypt function : mcrypt_module_get_algo_block_size(MCRYPT_RIJNDAEL_256, NULL) is 32. The key lengths from all three libraries is 32.
Jamaal On Saturday, December 22, 2012 8:47:15 PM UTC-5, Mouse wrote: > > The simple answer for AES is you can't. AES allows three key lengths (128, > 192, 256 bits), but only one block size (128 bits). AES prototype Rijndael > allowed three block sizes as well. > > Perhaps by Rijndael-256 they meant only the key length? In that case I > would check the encryption mode, padding, etc. match what that server is > set up with. > -- > Regards, > Mouse > On Dec 22, 2012 8:30 PM, "Jamaal Scarlett" > <[email protected]<javascript:>> > wrote: > >> I need to use AES, the server I am communicating with is using >> mcrypt with the encryption mode set to RIJNDAEL_256. From what I have >> found online, this is a non-standard algorithm. I have tried both crypto++ >> and OpenSSL's crypto library and while their encrypted outputs match, I >> cannot get either to match the output from mcrypt. I would use mcrypt, but >> there is a memory leak in the init function of the version I am >> using(2.5.7) and I am unable to find the lib(libmcrypt.lib) file for any >> more recent version of the mcrypt library. >> >> Thanks for the help, >> Jamaal >> >> On Saturday, December 22, 2012 4:05:32 PM UTC-5, Jeffrey Walton wrote: >>> >>> >>> >>> On Dec 22, 12:27 pm, Jamaal Scarlett <[email protected]> >>> wrote: >>> > Thank you for the reply. Upon further reading, it looks like the 256 >>> in >>> > mcrypts RIJNDAEL_256 refers to the block cipher size. Does cryptopp >>> aes >>> > support a 32-bit block cipher size? >>> No, AES is a 16 byte block size. SHACAL2 has a larger block size if >>> you need it. >>> >>> I believe Zooko (correct me here) needed a cipher with a larger block >>> size and used SHACAL2 for Tahoe-LFS (http://en.wikipedia.org/wiki/ >>> Tahoe-LAFS <http://en.wikipedia.org/wiki/Tahoe-LAFS>). >>> >>> Jeff >>> >>> > On Saturday, December 22, 2012 4:11:58 AM UTC-5, Jeffrey Walton wrote: >>> > >>> > > On Dec 22, 2:21 am, Jamaal Scarlett <[email protected]> >>> wrote: >>> > > > Is it possible to change key lengths. On the wiki it states that >>> > > 16,24&32 byte keys are supported in aes but I cannot find any >>> documentation >>> > > on changing itbftomvthe default of 16. I am attempting to >>> encrypt/decrypt >>> > > data to communicate with a server using mcrypt rijndael 256, >>> however there >>> > > is a memory leak in the version of mcrypt we are using. Is 256 bit >>> > > supported? >>> > >>> > > Yes. All relevant objects take a key and key size. See, for example, >>> > >http://www.cryptopp.com/wiki/**CBC_mode<http://www.cryptopp.com/wiki/CBC_mode>. >>> > > >>> >>> >> -- >> You received this message because you are subscribed to the "Crypto++ >> Users" Google Group. >> To unsubscribe, send an email to >> [email protected]<javascript:> >> . >> More information about Crypto++ and this group is available at >> http://www.cryptopp.com. > > -- You received this message because you are subscribed to the "Crypto++ Users" Google Group. To unsubscribe, send an email to [email protected]. More information about Crypto++ and this group is available at http://www.cryptopp.com.
