diff --git a/tools/ndnsec-dsk-gen.hpp b/tools/ndnsec-dsk-gen.hpp
index b7d95e8..08332ee 100644
--- a/tools/ndnsec-dsk-gen.hpp
+++ b/tools/ndnsec-dsk-gen.hpp
@@ -10,7 +10,7 @@
 
 #include "ndnsec-util.hpp"
 
-int 
+int
 ndnsec_dsk_gen(int argc, char** argv)
 {
   using namespace ndn;
@@ -20,8 +20,8 @@
   char keyType = 'r';
   int keySize = 2048;
 
-  po::options_description desc("General Usage\n  ndnsec dsk-gen [-h] identity\nGeneral options");
-  desc.add_options()
+  po::options_description description("General Usage\n  ndnsec dsk-gen [-h] identity\nGeneral options");
+  description.add_options()
     ("help,h", "produce help message")
     ("identity,i", po::value<std::string>(&identityName), "identity name, for example, /ndn/ucla.edu/alice")
     // ("type,t", po::value<char>(&keyType)->default_value('r'), "optional, key type, r for RSA key (default)")
@@ -32,128 +32,112 @@
   p.add("identity", 1);
 
   po::variables_map vm;
-  po::store(po::command_line_parser(argc, argv).options(desc).positional(p).run(), vm);
-  po::notify(vm);
-
-  if (vm.count("help"))
+  try
     {
-      std::cerr << desc << std::endl;
+      po::store(po::command_line_parser(argc, argv).options(description).positional(p).run(),
+                vm);
+      po::notify(vm);
+    }
+  catch (const std::exception& e)
+    {
+      std::cerr << "ERROR: " << e.what() << std::endl;
+      std::cerr << description << std::endl;
+      return 1;
+    }
+
+  if (vm.count("help") != 0)
+    {
+      std::cerr << description << std::endl;
       return 0;
     }
 
-  if (0 == vm.count("identity"))
+  if (vm.count("identity") == 0)
     {
       std::cerr << "identity must be specified" << std::endl;
-      std::cerr << desc << std::endl;
+      std::cerr << description << std::endl;
       return 1;
     }
 
   shared_ptr<IdentityCertificate> kskCert;
   Name signingCertName;
-  try
+
+  KeyChain keyChain;
+
+  Name defaultCertName = keyChain.getDefaultCertificateNameForIdentity(identityName);
+  bool isDefaultDsk = false;
+  if (defaultCertName.get(-3).toEscapedString().substr(0,4) == "dsk-")
+    isDefaultDsk = true;
+
+  if (isDefaultDsk)
     {
-      KeyChain keyChain;
+      shared_ptr<IdentityCertificate> dskCert = keyChain.getCertificate(defaultCertName);
+      SignatureSha256WithRsa sha256sig(dskCert->getSignature());
 
-      Name defaultCertName = keyChain.getDefaultCertificateNameForIdentity(identityName);
-      bool isDefaultDsk = false;
-      if(defaultCertName.get(-3).toEscapedString().substr(0,4) == "dsk-")
-        isDefaultDsk = true;
+      Name keyLocatorName = sha256sig.getKeyLocator().getName(); // will throw exception if keylocator is absent or it is not a name
 
-      if(isDefaultDsk)
-        {
-          shared_ptr<IdentityCertificate> dskCert = keyChain.getCertificate(defaultCertName);
-          SignatureSha256WithRsa sha256sig(dskCert->getSignature());
-
-          Name keyLocatorName = sha256sig.getKeyLocator().getName(); // will throw exception if keylocator is absent or it is not a name
-
-          Name kskName = IdentityCertificate::certificateNameToPublicKeyName(keyLocatorName);
-          Name kskCertName = keyChain.getDefaultCertificateNameForKey(kskName);
-          signingCertName = kskCertName;
-          kskCert = keyChain.getCertificate(kskCertName);
-        }
-      else
-        {
-          signingCertName = defaultCertName;
-          kskCert = keyChain.getCertificate(defaultCertName);
-        }
+      Name kskName = IdentityCertificate::certificateNameToPublicKeyName(keyLocatorName);
+      Name kskCertName = keyChain.getDefaultCertificateNameForKey(kskName);
+      signingCertName = kskCertName;
+      kskCert = keyChain.getCertificate(kskCertName);
     }
-  catch(SignatureSha256WithRsa::Error& e)
+  else
     {
-      std::cerr << "ERROR: " << e.what() << std::endl;
-      return 1;
-    }
-  catch(KeyLocator::Error& e)
-    {
-      std::cerr << "ERROR: " << e.what() << std::endl;
-      return 1;
-    }
-  catch(SecPublicInfo::Error& e)
-    {
-      std::cerr << "ERROR: " << e.what() << std::endl;
-      return 1;
+      signingCertName = defaultCertName;
+      kskCert = keyChain.getCertificate(defaultCertName);
     }
 
-  if(!static_cast<bool>(kskCert))
+  if (!static_cast<bool>(kskCert))
     {
       std::cerr << "ERROR: no KSK certificate." << std::endl;
       return 1;
     }
 
-  try
+  Name newKeyName;
+  switch (keyType)
     {
-      KeyChain keyChain;
-      Name newKeyName;
-      switch(keyType)
-        {
-        case 'r':
+    case 'r':
+      {
+        newKeyName = keyChain.generateRSAKeyPair(Name(identityName), false, keySize);
+        if (0 == newKeyName.size())
           {
-            newKeyName = keyChain.generateRSAKeyPair(Name(identityName), false, keySize);
-            if(0 == newKeyName.size())
-              {
-                std::cerr << "fail to generate key!" << std::endl;
-                return 1;
-              }
-            break;
+            std::cerr << "fail to generate key!" << std::endl;
+            return 1;
           }
-        default:
-          std::cerr << "Unrecongized key type" << "\n";
-          std::cerr << desc << std::endl;
-          return 1;
-        }
-    
-      Name certName = newKeyName.getPrefix(-1);
-      certName.append("KEY").append(newKeyName.get(-1)).append("ID-CERT").appendVersion();
-
-      shared_ptr<IdentityCertificate> certificate = make_shared<IdentityCertificate>();
-      certificate->setName(certName);
-      certificate->setNotBefore(kskCert->getNotBefore());
-      certificate->setNotAfter(kskCert->getNotAfter());
-
-      certificate->setPublicKeyInfo(*keyChain.getPublicKey(newKeyName));
-
-      const std::vector<CertificateSubjectDescription>& subList = kskCert->getSubjectDescriptionList();
-      std::vector<CertificateSubjectDescription>::const_iterator it = subList.begin();
-      for(; it != subList.end(); it++)
-        certificate->addSubjectDescription(*it);
-      
-      certificate->encode();
-
-      keyChain.sign(*certificate, signingCertName);
-
-      keyChain.addCertificateAsIdentityDefault(*certificate);
-
-      return 0;
-    }
-  catch(SecPublicInfo::Error& e)
-    {
-      std::cerr << "ERROR: " << e.what() << std::endl;
+        break;
+      }
+    default:
+      std::cerr << "Unrecongized key type" << "\n";
+      std::cerr << description << std::endl;
       return 1;
     }
-  catch(SecTpm::Error& e)
-    {
-      std::cerr << "ERROR: " << e.what() << std::endl;
-      return 1;
-    }
+
+  Name certName = newKeyName.getPrefix(-1);
+  certName.append("KEY")
+    .append(newKeyName.get(-1))
+    .append("ID-CERT")
+    .appendVersion();
+
+  shared_ptr<IdentityCertificate> certificate = make_shared<IdentityCertificate>();
+  certificate->setName(certName);
+  certificate->setNotBefore(kskCert->getNotBefore());
+  certificate->setNotAfter(kskCert->getNotAfter());
+
+  certificate->setPublicKeyInfo(*keyChain.getPublicKey(newKeyName));
+
+  const std::vector<CertificateSubjectDescription>& subList =
+    kskCert->getSubjectDescriptionList();
+
+  for (std::vector<CertificateSubjectDescription>::const_iterator it = subList.begin();
+       it != subList.end(); it++)
+    certificate->addSubjectDescription(*it);
+
+  certificate->encode();
+
+  keyChain.sign(*certificate, signingCertName);
+
+  keyChain.addCertificateAsIdentityDefault(*certificate);
+
+  return 0;
 }
 
 #endif //NDNSEC_DSK_GEN_HPP