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, 24 insertions, 37 deletions

diff --git a/sha3.h b/sha3.h
index 6a8704c8..04c23260 100644
--- a/sha3.h
+++ b/sha3.h
@@ -36,12 +36,14 @@ public:
 	SHA3(unsigned int digestSize) : m_digestSize(digestSize) {Restart();}

 	unsigned int DigestSize() const {return m_digestSize;}

 	std::string AlgorithmName() const {return "SHA3-" + IntToString(m_digestSize*8);}

+	CRYPTOPP_CONSTEXPR static const char* StaticAlgorithmName() { return "SHA3"; }

 	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;}

 

@@ -50,56 +52,41 @@ protected:
 };

 

 //! \class SHA3_224

-//! \brief SHA3-224 message digest

-//! \since Crypto++ 5.6.2

-class SHA3_224 : public SHA3

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

+//! \brief SHA3-X message digest, template for more fine-grained typedefs

+//! \since Crypto++ 5.7.0

+template<unsigned int digestSize>

+class SHA3_Final : public SHA3

 {

 public:

-	CRYPTOPP_CONSTANT(DIGESTSIZE = 28)

-

-	//! \brief Construct a SHA3-224 message digest

-	SHA3_224() : SHA3(DIGESTSIZE) {}

-	CRYPTOPP_CONSTEXPR static const char *StaticAlgorithmName() {return "SHA3-224";}

+	CRYPTOPP_CONSTANT(DIGESTSIZE = digestSize)

+	CRYPTOPP_CONSTANT(BLOCKSIZE = 200 - 2 * DIGESTSIZE)

+

+	//! \brief Construct a SHA3-X message digest

+	SHA3_Final() : SHA3(DIGESTSIZE) {}

+	static std::string StaticAlgorithmName() { return "SHA3-" + 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 SHA3_224

+//! \brief SHA3-224 message digest

+//! \since Crypto++ 5.6.2

+typedef SHA3_Final<28> SHA3_224;

 //! \class SHA3_256

 //! \brief SHA3-256 message digest

 //! \since Crypto++ 5.6.2

-class SHA3_256 : public SHA3

-{

-public:

-	CRYPTOPP_CONSTANT(DIGESTSIZE = 32)

-

-	//! \brief Construct a SHA3-256 message digest

-	SHA3_256() : SHA3(DIGESTSIZE) {}

-	CRYPTOPP_CONSTEXPR static const char *StaticAlgorithmName() {return "SHA3-256";}

-};

-

+typedef SHA3_Final<32> SHA3_256;

 //! \class SHA3_384

 //! \brief SHA3-384 message digest

 //! \since Crypto++ 5.6.2

-class SHA3_384 : public SHA3

-{

-public:

-	CRYPTOPP_CONSTANT(DIGESTSIZE = 48)

-

-	//! \brief Construct a SHA3-384 message digest

-	SHA3_384() : SHA3(DIGESTSIZE) {}

-	CRYPTOPP_CONSTEXPR static const char *StaticAlgorithmName() {return "SHA3-384";}

-};

-

+typedef SHA3_Final<48> SHA3_384;

 //! \class SHA3_512

 //! \brief SHA3-512 message digest

 //! \since Crypto++ 5.6.2

-class SHA3_512 : public SHA3

-{

-public:

-	CRYPTOPP_CONSTANT(DIGESTSIZE = 64)

-

-	//! \brief Construct a SHA3-512 message digest

-	SHA3_512() : SHA3(DIGESTSIZE) {}

-	CRYPTOPP_CONSTEXPR static const char *StaticAlgorithmName() {return "SHA3-512";}

-};

+typedef SHA3_Final<64> SHA3_512;

 

 NAMESPACE_END