1 files changed, 94 insertions, 0 deletions
diff --git a/doc/examples/dsa_ver.cpp b/doc/examples/dsa_ver.cpp
new file mode 100644
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+++ b/doc/examples/dsa_ver.cpp
@@ -0,0 +1,94 @@
+/*
+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 ([email protected]), August 5, 2002
+   Updated to use X.509 format keys, October 21, 2002
+
+This file is in the public domain
+*/
+
+#include <iostream>
+#include <iomanip>
+#include <fstream>
+#include <cstdlib>
+#include <string>
+
+#include <botan/botan.h>
+#include <botan/look_pk.h>
+#include <botan/dsa.h>
+using namespace Botan;
+
+SecureVector<byte> 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;
+      }
+
+   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);
+
+      LibraryInitializer init;
+
+      std::auto_ptr<X509_PublicKey> key(X509::load_key(argv[1]));
+      DSA_PublicKey* dsakey = dynamic_cast<DSA_PublicKey*>(key.get());
+      if(!dsakey)
+         {
+         std::cout << "The loaded key is not a DSA key!\n";
+         return 1;
+         }
+
+      SecureVector<byte> sig = b64_decode(sigstr);
+
+      Pipe pipe(new PK_Verifier_Filter(
+                   get_pk_verifier(*dsakey, "EMSA1(SHA-1)"), sig
+                   )
+         );
+
+      pipe.start_msg();
+      message >> pipe;
+      pipe.end_msg();
+
+      byte result = 0;
+      pipe.read(result);
+
+      if(result)
+         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;
+   }