/* Grab an DSA public key from the file given as an argument, grab a signature from another file, and verify the message (which, suprise, is also in a file). The signature format isn't particularly standard, but it's not bad. It's simply the IEEE 1363 signature format, encoded into base64 with a trailing newline Written by Jack Lloyd (lloyd@randombit.net), August 5, 2002 Updated to use X.509 format keys, October 21, 2002 This file is in the public domain */ #include #include #include #include #include #include #include #include #include using namespace Botan; SecureVector b64_decode(const std::string& in) { Pipe pipe(new Base64_Decoder); pipe.process_msg(in); return pipe.read_all(); } int main(int argc, char* argv[]) { if(argc != 4) { std::cout << "Usage: " << argv[0] << " keyfile messagefile sigfile" << std::endl; return 1; } Botan::LibraryInitializer init; std::ifstream message(argv[2]); if(!message) { std::cout << "Couldn't read the message file." << std::endl; return 1; } std::ifstream sigfile(argv[3]); if(!sigfile) { std::cout << "Couldn't read the signature file." << std::endl; return 1; } try { std::string sigstr; getline(sigfile, sigstr); std::auto_ptr key(X509::load_key(argv[1])); DSA_PublicKey* dsakey = dynamic_cast(key.get()); if(!dsakey) { std::cout << "The loaded key is not a DSA key!\n"; return 1; } SecureVector sig = b64_decode(sigstr); std::auto_ptr ver(get_pk_verifier(*dsakey, "EMSA1(SHA-1)")); DataSource_Stream in(message); byte buf[4096] = { 0 }; while(u32bit got = in.read(buf, sizeof(buf))) ver->update(buf, got); bool ok = ver->check_signature(sig); if(ok) std::cout << "Signature verified\n"; else std::cout << "Signature did NOT verify\n"; } catch(std::exception& e) { std::cout << "Exception caught: " << e.what() << std::endl; return 1; } return 0; }