314 lines
9.0 KiB
C++
314 lines
9.0 KiB
C++
// siphash.h - written and placed in public domain by Jeffrey Walton.
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/// \file siphash.h
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/// \brief Classes for SipHash message authentication code
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/// \details SipHash computes a 64-bit or 128-bit message authentication code from a variable-length
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/// message and 128-bit secret key. It was designed to be efficient even for short inputs, with
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/// performance comparable to non-cryptographic hash functions.
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/// \details To create a SipHash-2-4 object with a 64-bit MAC use code similar to the following.
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/// <pre> SecByteBlock key(16);
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/// prng.GenerateBlock(key, key.size());
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///
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/// SipHash<2,4,false> hash(key, key.size());
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/// hash.Update(...);
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/// hash.Final(...);</pre>
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/// \details To create a SipHash-2-4 object with a 128-bit MAC use code similar to the following.
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/// <pre> SecByteBlock key(16);
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/// prng.GenerateBlock(key, key.size());
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///
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/// SipHash<2,4,true> hash(key, key.size());
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/// hash.Update(...);
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/// hash.Final(...);</pre>
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/// \sa Jean-Philippe Aumasson and Daniel J. Bernstein <A HREF="http://131002.net/siphash/siphash.pdf">SipHash:
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/// a fast short-input PRF</A>
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/// \since Crypto++ 6.0
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#ifndef CRYPTOPP_SIPHASH_H
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#define CRYPTOPP_SIPHASH_H
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#include "cryptlib.h"
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#include "secblock.h"
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#include "misc.h"
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NAMESPACE_BEGIN(CryptoPP)
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/// \brief SipHash message authentication code information
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/// \tparam T_128bit flag indicating 128-bit (true) versus 64-bit (false) digest size
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template <bool T_128bit>
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class SipHash_Info : public FixedKeyLength<16>
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{
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public:
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CRYPTOPP_STATIC_CONSTEXPR const char* StaticAlgorithmName() {return "SipHash";}
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CRYPTOPP_CONSTANT(DIGESTSIZE = (T_128bit ? 16 : 8));
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};
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/// \brief SipHash message authentication code base class
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/// \tparam C the number of compression rounds
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/// \tparam D the number of finalization rounds
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/// \tparam T_128bit flag indicating 128-bit (true) versus 64-bit (false) digest size
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template <unsigned int C, unsigned int D, bool T_128bit>
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class SipHash_Base : public MessageAuthenticationCode, public SipHash_Info<T_128bit>
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{
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public:
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static std::string StaticAlgorithmName() {
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return std::string(SipHash_Info<T_128bit>::StaticAlgorithmName())+"-"+IntToString(C)+"-"+IntToString(D);
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}
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virtual ~SipHash_Base() {}
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SipHash_Base() : m_idx(0) {}
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virtual unsigned int DigestSize() const
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{return SipHash_Info<T_128bit>::DIGESTSIZE;}
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virtual size_t MinKeyLength() const
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{return SipHash_Info<T_128bit>::MIN_KEYLENGTH;}
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virtual size_t MaxKeyLength() const
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{return SipHash_Info<T_128bit>::MAX_KEYLENGTH;}
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virtual size_t DefaultKeyLength() const
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{return SipHash_Info<T_128bit>::DEFAULT_KEYLENGTH;}
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virtual size_t GetValidKeyLength(size_t keylength) const
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{CRYPTOPP_UNUSED(keylength); return SipHash_Info<T_128bit>::DEFAULT_KEYLENGTH;}
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virtual IV_Requirement IVRequirement() const
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{return SimpleKeyingInterface::NOT_RESYNCHRONIZABLE;}
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virtual unsigned int IVSize() const
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{return 0;}
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virtual unsigned int OptimalBlockSize() const
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{return sizeof(word64);}
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virtual unsigned int OptimalDataAlignment () const
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{return GetAlignmentOf<word64>();}
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virtual void Update(const byte *input, size_t length);
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virtual void TruncatedFinal(byte *digest, size_t digestSize);
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protected:
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virtual void UncheckedSetKey(const byte *key, unsigned int length, const NameValuePairs ¶ms);
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virtual void Restart();
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inline void SIPROUND()
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{
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m_v[0] += m_v[1];
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m_v[1] = rotlConstant<13>(m_v[1]);
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m_v[1] ^= m_v[0];
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m_v[0] = rotlConstant<32>(m_v[0]);
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m_v[2] += m_v[3];
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m_v[3] = rotlConstant<16>(m_v[3]);
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m_v[3] ^= m_v[2];
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m_v[0] += m_v[3];
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m_v[3] = rotlConstant<21>(m_v[3]);
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m_v[3] ^= m_v[0];
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m_v[2] += m_v[1];
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m_v[1] = rotlConstant<17>(m_v[1]);
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m_v[1] ^= m_v[2];
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m_v[2] = rotlConstant<32>(m_v[2]);
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}
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private:
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FixedSizeSecBlock<word64, 4> m_v;
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FixedSizeSecBlock<word64, 2> m_k;
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FixedSizeSecBlock<word64, 2> m_b;
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// Tail bytes
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FixedSizeSecBlock<byte, 8> m_acc;
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size_t m_idx;
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};
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/// \brief SipHash message authentication code
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/// \tparam C the number of compression rounds
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/// \tparam D the number of finalization rounds
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/// \tparam T_128bit flag indicating 128-bit (true) versus 64-bit (false) digest size
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/// \details SipHash computes a 64-bit or 128-bit message authentication code from a variable-length
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/// message and 128-bit secret key. It was designed to be efficient even for short inputs, with
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/// performance comparable to non-cryptographic hash functions.
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/// \details To create a SipHash-2-4 object with a 64-bit MAC use code similar to the following.
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/// <pre> SecByteBlock key(16);
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/// prng.GenerateBlock(key, key.size());
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///
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/// SipHash<2,4,false> hash(key, key.size());
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/// hash.Update(...);
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/// hash.Final(...);</pre>
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/// \details To create a SipHash-2-4 object with a 128-bit MAC use code similar to the following.
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/// <pre> SecByteBlock key(16);
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/// prng.GenerateBlock(key, key.size());
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///
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/// SipHash<2,4,true> hash(key, key.size());
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/// hash.Update(...);
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/// hash.Final(...);</pre>
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/// \sa Jean-Philippe Aumasson and Daniel J. Bernstein <A HREF="http://131002.net/siphash/siphash.pdf">SipHash:
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/// a fast short-input PRF</A>
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/// \since Crypto++ 6.0
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template <unsigned int C=2, unsigned int D=4, bool T_128bit=false>
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class SipHash : public SipHash_Base<C, D, T_128bit>
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{
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public:
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/// \brief Create a SipHash
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SipHash()
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{this->UncheckedSetKey(NULLPTR, 0, g_nullNameValuePairs);}
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/// \brief Create a SipHash
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/// \param key a byte array used to key the cipher
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/// \param length the size of the byte array, in bytes
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SipHash(const byte *key, unsigned int length)
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{this->ThrowIfInvalidKeyLength(length);
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this->UncheckedSetKey(key, length, g_nullNameValuePairs);}
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};
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template <unsigned int C, unsigned int D, bool T_128bit>
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void SipHash_Base<C,D,T_128bit>::Update(const byte *input, size_t length)
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{
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CRYPTOPP_ASSERT((input && length) || !length);
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if (!length) return;
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if (m_idx)
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{
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size_t head = STDMIN(size_t(8U-m_idx), length);
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memcpy(m_acc+m_idx, input, head);
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m_idx += head; input += head; length -= head;
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if (m_idx == 8)
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{
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word64 m = GetWord<word64>(true, LITTLE_ENDIAN_ORDER, m_acc);
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m_v[3] ^= m;
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for (unsigned int i = 0; i < C; ++i)
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SIPROUND();
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m_v[0] ^= m;
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m_b[0] += 8;
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m_idx = 0;
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}
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}
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while (length >= 8)
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{
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word64 m = GetWord<word64>(false, LITTLE_ENDIAN_ORDER, input);
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m_v[3] ^= m;
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for (unsigned int i = 0; i < C; ++i)
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SIPROUND();
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m_v[0] ^= m;
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m_b[0] += 8;
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input += 8;
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length -= 8;
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}
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CRYPTOPP_ASSERT(length < 8);
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size_t tail = length % 8;
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if (tail)
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{
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memcpy(m_acc+m_idx, input, tail);
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m_idx += tail;
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}
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}
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template <unsigned int C, unsigned int D, bool T_128bit>
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void SipHash_Base<C,D,T_128bit>::TruncatedFinal(byte *digest, size_t digestSize)
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{
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CRYPTOPP_ASSERT(digest); // Pointer is valid
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ThrowIfInvalidTruncatedSize(digestSize);
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// The high octet holds length and is digested mod 256
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m_b[0] += m_idx; m_b[0] <<= 56U;
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switch (m_idx)
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{
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case 7:
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m_b[0] |= ((word64)m_acc[6]) << 48;
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// fall through
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case 6:
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m_b[0] |= ((word64)m_acc[5]) << 40;
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// fall through
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case 5:
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m_b[0] |= ((word64)m_acc[4]) << 32;
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// fall through
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case 4:
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m_b[0] |= ((word64)m_acc[3]) << 24;
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// fall through
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case 3:
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m_b[0] |= ((word64)m_acc[2]) << 16;
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// fall through
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case 2:
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m_b[0] |= ((word64)m_acc[1]) << 8;
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// fall through
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case 1:
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m_b[0] |= ((word64)m_acc[0]);
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// fall through
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case 0:
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break;
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}
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m_v[3] ^= m_b[0];
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for (unsigned int i=0; i<C; i++)
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SIPROUND();
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m_v[0] ^= m_b[0];
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if (T_128bit)
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m_v[2] ^= 0xee;
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else
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m_v[2] ^= 0xff;
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for (unsigned int i=0; i<D; i++)
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SIPROUND();
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m_b[0] = m_v[0] ^ m_v[1] ^ m_v[2] ^ m_v[3];
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m_b[0] = ConditionalByteReverse(LITTLE_ENDIAN_ORDER, m_b[0]);
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if (T_128bit)
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{
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m_v[1] ^= 0xdd;
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for (unsigned int i = 0; i<D; ++i)
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SIPROUND();
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m_b[1] = m_v[0] ^ m_v[1] ^ m_v[2] ^ m_v[3];
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m_b[1] = ConditionalByteReverse(LITTLE_ENDIAN_ORDER, m_b[1]);
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}
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memcpy_s(digest, digestSize, m_b.begin(), STDMIN(digestSize, (size_t)SipHash_Info<T_128bit>::DIGESTSIZE));
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Restart();
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}
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template <unsigned int C, unsigned int D, bool T_128bit>
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void SipHash_Base<C,D,T_128bit>::UncheckedSetKey(const byte *key, unsigned int length, const NameValuePairs ¶ms)
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{
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CRYPTOPP_UNUSED(params);
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if (key && length)
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{
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m_k[0] = GetWord<word64>(false, LITTLE_ENDIAN_ORDER, key);
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m_k[1] = GetWord<word64>(false, LITTLE_ENDIAN_ORDER, key+8);
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}
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else
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{
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// Avoid Coverity finding
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m_k[0] = m_k[1] = 0;
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}
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Restart();
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}
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template <unsigned int C, unsigned int D, bool T_128bit>
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void SipHash_Base<C,D,T_128bit>::Restart ()
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{
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m_v[0] = W64LIT(0x736f6d6570736575);
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m_v[1] = W64LIT(0x646f72616e646f6d);
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m_v[2] = W64LIT(0x6c7967656e657261);
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m_v[3] = W64LIT(0x7465646279746573);
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m_v[3] ^= m_k[1];
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m_v[2] ^= m_k[0];
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m_v[1] ^= m_k[1];
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m_v[0] ^= m_k[0];
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if (T_128bit)
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{
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m_v[1] ^= 0xee;
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}
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m_idx = 0;
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m_b[0] = 0;
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}
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NAMESPACE_END
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#endif // CRYPTOPP_SIPHASH_H
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