add CFB mode FIPS variant

4 files changed, 34 insertions, 8 deletions

diff --git a/dlltest.cpp b/dlltest.cpp
index a8b28133..ed9337a0 100644
--- a/dlltest.cpp
+++ b/dlltest.cpp
@@ -60,20 +60,20 @@ void FIPS140_SampleApplication()
 	byte ciphertext[24];
 	byte decrypted[24];
 
-	CFB_Mode<DES_EDE3>::Encryption encryption_DES_EDE3_CBC;
-	encryption_DES_EDE3_CBC.SetKeyWithIV(key, sizeof(key), iv);
-	encryption_DES_EDE3_CBC.ProcessString(ciphertext, plaintext, 24);
+	CFB_FIPS_Mode<DES_EDE3>::Encryption encryption_DES_EDE3_CFB;
+	encryption_DES_EDE3_CFB.SetKeyWithIV(key, sizeof(key), iv);
+	encryption_DES_EDE3_CFB.ProcessString(ciphertext, plaintext, 23);
 
-	CFB_Mode<DES_EDE3>::Decryption decryption_DES_EDE3_CBC;
-	decryption_DES_EDE3_CBC.SetKeyWithIV(key, sizeof(key), iv);
-	decryption_DES_EDE3_CBC.ProcessString(decrypted, ciphertext, 24);
+	CFB_FIPS_Mode<DES_EDE3>::Decryption decryption_DES_EDE3_CFB;
+	decryption_DES_EDE3_CFB.SetKeyWithIV(key, sizeof(key), iv);
+	decryption_DES_EDE3_CFB.ProcessString(decrypted, ciphertext, 24);
 
 	if (memcmp(plaintext, decrypted, 24) != 0)
 	{
-		cerr << "DES-EDE3-CBC Encryption/decryption failed.\n";
+		cerr << "DES-EDE3-CFB Encryption/decryption failed.\n";
 		abort();
 	}
-	cout << "3. DES-EDE3-CBC Encryption/decryption succeeded.\n";
+	cout << "3. DES-EDE3-CFB Encryption/decryption succeeded.\n";
 
 	// hash
 	const byte message[] = {'a', 'b', 'c'};
diff --git a/modes.h b/modes.h
index ed3f1b0a..66b66384 100644
--- a/modes.h
+++ b/modes.h
@@ -328,6 +328,21 @@ struct CFB_Mode_ExternalCipher : public CipherModeDocumentation
 	typedef CipherModeFinalTemplate_ExternalCipher<ConcretePolicyHolder<Empty, CFB_DecryptionTemplate<AbstractPolicyHolder<CFB_CipherAbstractPolicy, CFB_ModePolicy> > > > Decryption;
 };
 
+//! CFB mode FIPS variant, requiring full block plaintext according to FIPS 800-38A
+template <class CIPHER>
+struct CFB_FIPS_Mode : public CipherModeDocumentation
+{
+	typedef CipherModeFinalTemplate_CipherHolder<CPP_TYPENAME CIPHER::Encryption, ConcretePolicyHolder<Empty, CFB_RequireFullDataBlocks<CFB_EncryptionTemplate<AbstractPolicyHolder<CFB_CipherAbstractPolicy, CFB_ModePolicy> > > > > Encryption;
+	typedef CipherModeFinalTemplate_CipherHolder<CPP_TYPENAME CIPHER::Encryption, ConcretePolicyHolder<Empty, CFB_RequireFullDataBlocks<CFB_DecryptionTemplate<AbstractPolicyHolder<CFB_CipherAbstractPolicy, CFB_ModePolicy> > > > > Decryption;
+};
+
+//! CFB mode FIPS variant, requiring full block plaintext according to FIPS 800-38A, external cipher
+struct CFB_FIPS_Mode_ExternalCipher : public CipherModeDocumentation
+{
+	typedef CipherModeFinalTemplate_ExternalCipher<ConcretePolicyHolder<Empty, CFB_RequireFullDataBlocks<CFB_EncryptionTemplate<AbstractPolicyHolder<CFB_CipherAbstractPolicy, CFB_ModePolicy> > > > > Encryption;
+	typedef CipherModeFinalTemplate_ExternalCipher<ConcretePolicyHolder<Empty, CFB_RequireFullDataBlocks<CFB_DecryptionTemplate<AbstractPolicyHolder<CFB_CipherAbstractPolicy, CFB_ModePolicy> > > > > Decryption;
+};
+
 CRYPTOPP_DLL_TEMPLATE_CLASS AdditiveCipherTemplate<AbstractPolicyHolder<AdditiveCipherAbstractPolicy, OFB_ModePolicy> >;
 
 //! OFB mode
diff --git a/strciphr.cpp b/strciphr.cpp
index 3394b204..4cb71c69 100644
--- a/strciphr.cpp
+++ b/strciphr.cpp
@@ -119,6 +119,8 @@ void CFB_CipherTemplate<BASE>::Resynchronize(const byte *iv)
 template <class BASE>
 void CFB_CipherTemplate<BASE>::ProcessData(byte *outString, const byte *inString, unsigned int length)
 {
+	assert(length % MandatoryBlockSize() == 0);
+
 	PolicyInterface &policy = AccessPolicy();
 	unsigned int bytesPerIteration = policy.GetBytesPerIteration();
 	unsigned int alignment = policy.GetAlignment();
diff --git a/strciphr.h b/strciphr.h
index eb1d22fe..15d2bb33 100644
--- a/strciphr.h
+++ b/strciphr.h
@@ -251,10 +251,19 @@ class CRYPTOPP_NO_VTABLE CFB_DecryptionTemplate : public CFB_CipherTemplate<BASE
 	void CombineMessageAndShiftRegister(byte *output, byte *reg, const byte *message, unsigned int length);
 };
 
+template <class BASE>
+class CFB_RequireFullDataBlocks : public BASE
+{
+public:
+	unsigned int MandatoryBlockSize() const {return OptimalBlockSize();}
+};
+
+/*
 CRYPTOPP_DLL_TEMPLATE_CLASS AbstractPolicyHolder<CFB_CipherAbstractPolicy, SymmetricCipher>;
 CRYPTOPP_DLL_TEMPLATE_CLASS CFB_CipherTemplate<AbstractPolicyHolder<CFB_CipherAbstractPolicy, SymmetricCipher> >;
 CRYPTOPP_DLL_TEMPLATE_CLASS CFB_EncryptionTemplate<>;
 CRYPTOPP_DLL_TEMPLATE_CLASS CFB_DecryptionTemplate<>;
+*/
 
 template <class BASE, class INFO = BASE>
 class SymmetricCipherFinal : public AlgorithmImpl<SimpleKeyingInterfaceImpl<BASE, INFO>, INFO>