On Monday, November 7, 2016 at 1:28:24 PM UTC-5, [email protected] wrote: > > I just spent a while finding a bug because feedbackSize was not specified > in my code. The > > CryptoPP::CFB_Mode<CryptoPP::AES>::Encryption aes(_bKey, sizeof(_bKey), _iv); > > should have been: > > CryptoPP::CFB_Mode<CryptoPP::AES>::Encryption aes(_bKey, sizeof(_bKey), _iv, > 1); > > > > I'm wondering why the CFB_Mode Encryption and Decryption constructors > don't automatically supply that? >
I believe the library uses a feedback size equal to the blocksize by default. The trouble you seem to be suffering is different settings among libraries. Others have had the trouble, too. Also see "Incorrect key size in PHP mcrypt when porting Crypto++ AES encryption to PHP's mcrypt", http://stackoverflow.com/q/4052594. If you have any suggestions to solve that interoperability problem, then I'd be delighted to hear them. Also, be careful of OFB mode and less-than-blocksize feedback size. In OFB mode the feedback size effectively controls the cycle length with 2^(m/2) for a m-bit block cipher. Jeff -- -- 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 Google Groups "Crypto++ Users" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. For more options, visit https://groups.google.com/d/optout.
