Templated Keccak and SHA3

templated Keccak and SHA3 to reduce code-size, added a
StaticAlgorithmName() to the base classes and restricted use of
constexpr to this new function in the base classes

1 files changed, 25 insertions, 37 deletions

diff --git a/keccak.h b/keccak.h
index d3580ec1..acdc3f3b 100644
--- a/keccak.h
+++ b/keccak.h
@@ -50,12 +50,15 @@ public:
 	Keccak(unsigned int digestSize) : m_digestSize(digestSize) {Restart();}

 	unsigned int DigestSize() const {return m_digestSize;}

 	std::string AlgorithmName() const {return "Keccak-" + IntToString(m_digestSize*8);}

+	CRYPTOPP_CONSTEXPR static const char* StaticAlgorithmName() { return "Keccak"; }

 	unsigned int OptimalDataAlignment() const {return GetAlignmentOf<word64>();}

 

 	void Update(const byte *input, size_t length);

 	void Restart();

 	void TruncatedFinal(byte *hash, size_t size);

 

+	//unsigned int BlockSize() const { return r(); } // that's the idea behind it

+

 protected:

 	inline unsigned int r() const {return 200 - 2 * m_digestSize;}

 

@@ -64,56 +67,41 @@ protected:
 };

 

 //! \class Keccak_224

-//! \brief Keccak-224 message digest

-//! \since Crypto++ 5.6.4

-class Keccak_224 : public Keccak

+//! \tparam DigestSize controls the digest size as a template parameter instead of a per-class constant

+//! \brief Keccak-X message digest, template for more fine-grained typedefs

+//! \since Crypto++ 5.7.0

+template<unsigned int digestSize>

+class Keccak_Final : public Keccak

 {

 public:

-	CRYPTOPP_CONSTANT(DIGESTSIZE = 28)

-

-	//! \brief Construct a Keccak-224 message digest

-	Keccak_224() : Keccak(DIGESTSIZE) {}

-	CRYPTOPP_CONSTEXPR static const char *StaticAlgorithmName() {return "Keccak-224";}

+	CRYPTOPP_CONSTANT(DIGESTSIZE = digestSize)

+	CRYPTOPP_CONSTANT(BLOCKSIZE = 200 - 2 * DIGESTSIZE)

+

+		//! \brief Construct a Keccak-X message digest

+	Keccak_Final() : Keccak(DIGESTSIZE) {}

+	static std::string StaticAlgorithmName() { return "Keccak-" + IntToString(DIGESTSIZE * 8); }

+	unsigned int BlockSize() const { return BLOCKSIZE; }

+private:

+	CRYPTOPP_COMPILE_ASSERT(BLOCKSIZE < 200); // ensure there was no underflow in the math

+	CRYPTOPP_COMPILE_ASSERT(BLOCKSIZE > DIGESTSIZE); // this is a general expectation by HMAC

 };

 

+//! \class Keccak_224

+//! \brief Keccak-224 message digest

+//! \since Crypto++ 5.6.4

+typedef Keccak_Final<28> Keccak_224;

 //! \class Keccak_256

 //! \brief Keccak-256 message digest

 //! \since Crypto++ 5.6.4

-class Keccak_256 : public Keccak

-{

-public:

-	CRYPTOPP_CONSTANT(DIGESTSIZE = 32)

-

-	//! \brief Construct a Keccak-256 message digest

-	Keccak_256() : Keccak(DIGESTSIZE) {}

-	CRYPTOPP_CONSTEXPR static const char *StaticAlgorithmName() {return "Keccak-256";}

-};

-

+typedef Keccak_Final<32> Keccak_256;

 //! \class Keccak_384

 //! \brief Keccak-384 message digest

 //! \since Crypto++ 5.6.4

-class Keccak_384 : public Keccak

-{

-public:

-	CRYPTOPP_CONSTANT(DIGESTSIZE = 48)

-

-	//! \brief Construct a Keccak-384 message digest

-	Keccak_384() : Keccak(DIGESTSIZE) {}

-	CRYPTOPP_CONSTEXPR static const char *StaticAlgorithmName() {return "Keccak-384";}

-};

-

+typedef Keccak_Final<48> Keccak_384;

 //! \class Keccak_512

 //! \brief Keccak-512 message digest

 //! \since Crypto++ 5.6.4

-class Keccak_512 : public Keccak

-{

-public:

-	CRYPTOPP_CONSTANT(DIGESTSIZE = 64)

-

-	//! \brief Construct a Keccak-512 message digest

-	Keccak_512() : Keccak(DIGESTSIZE) {}

-	CRYPTOPP_CONSTEXPR static const char *StaticAlgorithmName() {return "Keccak-512";}

-};

+typedef Keccak_Final<64> Keccak_512;

 

 NAMESPACE_END