diff --git a/cryptlib.h b/cryptlib.h
index eea3a0c5..76efe5d5 100644
--- a/cryptlib.h
+++ b/cryptlib.h
@@ -1475,6 +1475,12 @@ protected:
 	void ThrowIfInvalidDerivedLength(size_t length) const;
 };
 
+/// \brief Interface for password based key derivation functions
+/// \since Crypto++ 6.2
+struct PasswordBasedKeyDerivationFunction : public KeyDerivationFunction
+{
+};
+
 /// \brief Random Number Generator that does not produce random numbers
 /// \return reference that can be passed to functions that require a RandomNumberGenerator
 /// \details NullRNG() returns a reference that can be passed to functions that require a
diff --git a/pwdbased.h b/pwdbased.h
index 06a4b025..20828a91 100644
--- a/pwdbased.h
+++ b/pwdbased.h
@@ -16,10 +16,6 @@
 
 NAMESPACE_BEGIN(CryptoPP)
 
-struct PasswordBasedKeyDerivationFunction : public KeyDerivationFunction
-{
-};
-
 // ******************** PBKDF1 ********************
 
 /// \brief PBKDF1 from PKCS #5