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]> 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]. > 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.
