This is a bug that was fixed in version 5.2. Please upgrade to that version, or see this link for just the fix:
http://cvs.sourceforge.net/viewcvs.py/cryptopp/c5/pubkey.h?r1=1.4&r2=1.5 On Sun, Jul 04, 2004 at 09:39:03PM +0800, Quanm qiu wrote: > Hello.I am using Cryptopp5.1 on MS Windows 2003.The compiler is MS VC.net > 2003. I want to write a DSASignFile function just like RSASignFile.So I > write this: > void DSASignFile(const char *privFilename, const char *messageFilename, > const char *signatureFilename) > { > AutoSeededRandomPool rng; > FileSource privFile(privFilename, true, new HexDecoder); > DSA::Signer priv(privFile); > > FileSource f(messageFilename, true, new SignerFilter(rng, priv, new > HexEncoder(new FileSink(signatureFilename)))); > } > > But I always get a exception like "NullRNG: NullRNG should only be passed > to functions that don't need to generate random bytes" when I use this > function to sign a file.What is wrong? > Thank you very much! >
