code style: Don't use std:: inside .cpp files.
diff --git a/ndn-cpp/security/identity/memory-identity-storage.cpp b/ndn-cpp/security/identity/memory-identity-storage.cpp
index 95ab69b..164862e 100644
--- a/ndn-cpp/security/identity/memory-identity-storage.cpp
+++ b/ndn-cpp/security/identity/memory-identity-storage.cpp
@@ -42,7 +42,7 @@
 MemoryIdentityStorage::revokeIdentity()
 {
 #if 1
-  throw std::runtime_error("MemoryIdentityStorage::revokeIdentity not implemented");
+  throw runtime_error("MemoryIdentityStorage::revokeIdentity not implemented");
 #endif
 }
 
@@ -50,7 +50,7 @@
 MemoryIdentityStorage::getNewKeyName(const Name& identityName, bool useKsk)
 {
 #if 1
-  throw std::runtime_error("MemoryIdentityStorage::getNewKeyName not implemented");
+  throw runtime_error("MemoryIdentityStorage::getNewKeyName not implemented");
 #endif
 }
 
@@ -58,7 +58,7 @@
 MemoryIdentityStorage::doesKeyExist(const Name& keyName)
 {
 #if 1
-  throw std::runtime_error("MemoryIdentityStorage::doesKeyExist not implemented");
+  throw runtime_error("MemoryIdentityStorage::doesKeyExist not implemented");
 #endif
 }
 
@@ -79,7 +79,7 @@
 MemoryIdentityStorage::addKey(const Name& keyName, KeyType keyType, const Blob& publicKeyDer)
 {
 #if 1
-  throw std::runtime_error("MemoryIdentityStorage::addKey not implemented");
+  throw runtime_error("MemoryIdentityStorage::addKey not implemented");
 #endif
 }
 
@@ -87,7 +87,7 @@
 MemoryIdentityStorage::getKey(const Name& keyName)
 {
 #if 1
-  throw std::runtime_error("MemoryIdentityStorage::getKey not implemented");
+  throw runtime_error("MemoryIdentityStorage::getKey not implemented");
 #endif
 }
 
@@ -95,7 +95,7 @@
 MemoryIdentityStorage::activateKey(const Name& keyName)
 {
 #if 1
-  throw std::runtime_error("MemoryIdentityStorage::activateKey not implemented");
+  throw runtime_error("MemoryIdentityStorage::activateKey not implemented");
 #endif
 }
 
@@ -103,7 +103,7 @@
 MemoryIdentityStorage::deactivateKey(const Name& keyName)
 {
 #if 1
-  throw std::runtime_error("MemoryIdentityStorage::deactivateKey not implemented");
+  throw runtime_error("MemoryIdentityStorage::deactivateKey not implemented");
 #endif
 }
 
@@ -111,7 +111,7 @@
 MemoryIdentityStorage::doesCertificateExist(const Name& certificateName)
 {
 #if 1
-  throw std::runtime_error("MemoryIdentityStorage::doesCertificateExist not implemented");
+  throw runtime_error("MemoryIdentityStorage::doesCertificateExist not implemented");
 #endif
 }
 
@@ -119,7 +119,7 @@
 MemoryIdentityStorage::addCertificate(const IdentityCertificate& certificate)
 {
 #if 1
-  throw std::runtime_error("MemoryIdentityStorage::addCertificate not implemented");
+  throw runtime_error("MemoryIdentityStorage::addCertificate not implemented");
 #endif
 }
 
@@ -127,7 +127,7 @@
 MemoryIdentityStorage::getCertificate(const Name &certificateName, bool allowAny)
 {
 #if 1
-  throw std::runtime_error("MemoryIdentityStorage::getCertificate not implemented");
+  throw runtime_error("MemoryIdentityStorage::getCertificate not implemented");
 #endif
 }
 
@@ -141,7 +141,7 @@
 MemoryIdentityStorage::getDefaultKeyNameForIdentity(const Name& identityName)
 {
 #if 1
-  throw std::runtime_error("MemoryIdentityStorage::getDefaultKeyNameForIdentity not implemented");
+  throw runtime_error("MemoryIdentityStorage::getDefaultKeyNameForIdentity not implemented");
 #endif
 }
 
@@ -149,7 +149,7 @@
 MemoryIdentityStorage::getDefaultCertificateNameForKey(const Name& keyName)
 {
 #if 1
-  throw std::runtime_error("MemoryIdentityStorage::getDefaultCertificateNameForKey not implemented");
+  throw runtime_error("MemoryIdentityStorage::getDefaultCertificateNameForKey not implemented");
 #endif
 }
 
@@ -168,7 +168,7 @@
 MemoryIdentityStorage::setDefaultKeyNameForIdentity(const Name& keyName, const Name& identityNameCheck)
 {
 #if 1
-  throw std::runtime_error("MemoryIdentityStorage::setDefaultKeyNameForIdentity not implemented");
+  throw runtime_error("MemoryIdentityStorage::setDefaultKeyNameForIdentity not implemented");
 #endif
 }
 
@@ -176,7 +176,7 @@
 MemoryIdentityStorage::setDefaultCertificateNameForKey(const Name& keyName, const Name& certificateName)  
 {
 #if 1
-  throw std::runtime_error("MemoryIdentityStorage::setDefaultCertificateNameForKey not implemented");
+  throw runtime_error("MemoryIdentityStorage::setDefaultCertificateNameForKey not implemented");
 #endif
 }