diff --git a/include/ndn-cpp/security/certificate/identity-certificate.hpp b/include/ndn-cpp/security/certificate/identity-certificate.hpp
index d111acc..7ce95f9 100644
--- a/include/ndn-cpp/security/certificate/identity-certificate.hpp
+++ b/include/ndn-cpp/security/certificate/identity-certificate.hpp
@@ -49,6 +49,14 @@
   static bool
   isIdentityCertificate(const Certificate& certificate);
 
+  /**
+   * Get the public key name from the full certificate name.
+   * @param certificateName The full certificate name.
+   * @return The related public key name.
+   */
+  static Name
+  certificateNameToPublicKeyName(const Name& certificateName);
+  
 private:
   static bool
   isCorrectName(const Name& name);
diff --git a/src/security/certificate/identity-certificate.cpp b/src/security/certificate/identity-certificate.cpp
index 2e2ea79..95f6c1b 100644
--- a/src/security/certificate/identity-certificate.cpp
+++ b/src/security/certificate/identity-certificate.cpp
@@ -67,8 +67,18 @@
 void
 IdentityCertificate::setPublicKeyName()
 {
-  const Name& certificateName = getName();
+  publicKeyName_ = certificateNameToPublicKeyName(getName());
+}
 
+bool
+IdentityCertificate::isIdentityCertificate(const Certificate& certificate)
+{ 
+  return isCorrectName(certificate.getName()); 
+}
+
+Name
+IdentityCertificate::certificateNameToPublicKeyName(const Name& certificateName)
+{
   int i = certificateName.size() - 1;
   string idString("ID-CERT");
   for (; i >= 0; i--) {
@@ -83,13 +93,7 @@
       break;
   }
   
-  publicKeyName_ = tmpName.getSubName(0, i).append(tmpName.getSubName(i + 1, tmpName.size() - i - 1));
-}
-
-bool
-IdentityCertificate::isIdentityCertificate(const Certificate& certificate)
-{ 
-  return isCorrectName(certificate.getName()); 
+  return tmpName.getSubName(0, i).append(tmpName.getSubName(i + 1, tmpName.size() - i - 1));
 }
 
 }
diff --git a/src/security/identity/identity-manager.cpp b/src/security/identity/identity-manager.cpp
index 6ee3082..90bc043 100644
--- a/src/security/identity/identity-manager.cpp
+++ b/src/security/identity/identity-manager.cpp
@@ -187,9 +187,8 @@
   
 ptr_lib::shared_ptr<Signature>
 IdentityManager::signByCertificate(const uint8_t* buffer, size_t bufferLength, const Name& certificateName)
-{    
-  shared_ptr<IdentityCertificate> certificate = getCertificate(certificateName);
-  Name keyName = certificate->getPublicKeyName();
+{
+  Name keyName = IdentityCertificate::certificateNameToPublicKeyName(certificateName);
   shared_ptr<PublicKey> publicKey = privateKeyStorage_->getPublicKey(keyName.toUri());
 
   Blob sigBits = privateKeyStorage_->sign(buffer, bufferLength, keyName.toUri());
@@ -211,8 +210,7 @@
 void
 IdentityManager::signByCertificate(Data &data, const Name &certificateName, WireFormat& wireFormat)
 {
-  shared_ptr<IdentityCertificate> certificate = getCertificate(certificateName);
-  Name keyName = certificate->getPublicKeyName();
+  Name keyName = IdentityCertificate::certificateNameToPublicKeyName(certificateName);
   shared_ptr<PublicKey> publicKey = privateKeyStorage_->getPublicKey(keyName);
 
   // For temporary usage, we support RSA + SHA256 only, but will support more.