1 files changed, 91 insertions, 0 deletions
diff --git a/src/cli/dsa_ver.cpp b/src/cli/dsa_ver.cpp
new file mode 100644
index 000000000..64d60a5cf
--- /dev/null
+++ b/src/cli/dsa_ver.cpp
@@ -0,0 +1,91 @@
+/*
+* (C) 2014,2015 Jack Lloyd
+*
+* Botan is released under the Simplified BSD License (see license.txt)
+*/
+
+#include "apps.h"
+
+#if defined(BOTAN_HAS_DSA)
+
+#include <fstream>
+#include <botan/pubkey.h>
+#include <botan/dsa.h>
+#include <botan/base64.h>
+
+using namespace Botan;
+
+namespace {
+
+int dsa_verify(const std::vector<std::string> &args)
+   {
+   if(args.size() != 4)
+      {
+      std::cout << "Usage: " << args[0]
+                << " keyfile messagefile sigfile" << std::endl;
+      return 1;
+      }
+
+
+   try {
+      std::ifstream message(args[2], std::ios::binary);
+      if(!message)
+         {
+         std::cout << "Couldn't read the message file." << std::endl;
+         return 1;
+         }
+
+      std::ifstream sigfile(args[3]);
+      if(!sigfile)
+         {
+         std::cout << "Couldn't read the signature file." << std::endl;
+         return 1;
+         }
+
+      std::string sigstr;
+      getline(sigfile, sigstr);
+
+      std::unique_ptr<X509_PublicKey> key(X509::load_key(args[1]));
+      DSA_PublicKey* dsakey = dynamic_cast<DSA_PublicKey*>(key.get());
+
+      if(!dsakey)
+         {
+         std::cout << "The loaded key is not a DSA key!" << std::endl;
+         return 1;
+         }
+
+      secure_vector<byte> sig = base64_decode(sigstr);
+
+      PK_Verifier ver(*dsakey, "EMSA1(SHA-1)");
+
+      DataSource_Stream in(message);
+      byte buf[4096] = { 0 };
+      while(size_t got = in.read(buf, sizeof(buf)))
+         ver.update(buf, got);
+
+      const bool ok = ver.check_signature(sig);
+
+      if(ok)
+         {
+         std::cout << "Signature verified" << std::endl;
+         return 0;
+         }
+      else
+         {
+         std::cout << "Signature did NOT verify" << std::endl;
+         return 1;
+         }
+   }
+   catch(std::exception& e)
+      {
+      std::cout << "Exception caught: " << e.what() << std::endl;
+      return 2;
+      }
+   }
+
+REGISTER_APP(dsa_verify);
+
+}
+
+#endif
+