86 lines
3.9 KiB
C++
86 lines
3.9 KiB
C++
// chacha.h - written and placed in the public domain by Jeffrey Walton.
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// Based on Wei Dai's Salsa20 and Bernstein's reference ChaCha
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// family implementation at http://cr.yp.to/chacha.html.
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/// \file chacha.h
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/// \brief Classes for ChaCha8, ChaCha12 and ChaCha20 stream ciphers
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/// \details Crypto++ provides Bernstein and ECRYPT's ChaCha from <a href="http://cr.yp.to/chacha/chacha-20080128.pdf">ChaCha,
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/// a variant of Salsa20</a> (2008.01.28). Bernstein's implementation is _slightly_ different from the TLS working group's
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/// implementation for cipher suites <tt>TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305_SHA256</tt>,
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/// <tt>TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305_SHA256</tt>, and <tt>TLS_DHE_RSA_WITH_CHACHA20_POLY1305_SHA256</tt>.
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/// \since Crypto++ 5.6.4
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#ifndef CRYPTOPP_CHACHA_H
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#define CRYPTOPP_CHACHA_H
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#include "strciphr.h"
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#include "secblock.h"
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NAMESPACE_BEGIN(CryptoPP)
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/// \brief ChaCha stream cipher information
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/// \since Crypto++ 5.6.4
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template <unsigned int R>
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struct ChaCha_Info : public VariableKeyLength<32, 16, 32, 16, SimpleKeyingInterface::UNIQUE_IV, 8>, public FixedRounds<R>
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{
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CRYPTOPP_STATIC_CONSTEXPR const char* StaticAlgorithmName() {
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return (R==8?"ChaCha8":(R==12?"ChaCha12":(R==20?"ChaCha20":"ChaCha")));
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}
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};
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/// \brief ChaCha stream cipher implementation
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/// \since Crypto++ 5.6.4
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template <unsigned int R>
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class CRYPTOPP_NO_VTABLE ChaCha_Policy : public AdditiveCipherConcretePolicy<word32, 16>
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{
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protected:
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CRYPTOPP_CONSTANT(ROUNDS=FixedRounds<R>::ROUNDS)
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void CipherSetKey(const NameValuePairs ¶ms, const byte *key, size_t length);
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void OperateKeystream(KeystreamOperation operation, byte *output, const byte *input, size_t iterationCount);
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void CipherResynchronize(byte *keystreamBuffer, const byte *IV, size_t length);
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bool CipherIsRandomAccess() const {return false;} // TODO
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void SeekToIteration(lword iterationCount);
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unsigned int GetAlignment() const;
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unsigned int GetOptimalBlockSize() const;
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FixedSizeAlignedSecBlock<word32, 16> m_state;
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};
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/// \brief ChaCha8 stream cipher
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/// \sa <a href="http://cr.yp.to/chacha/chacha-20080128.pdf">ChaCha, a variant of Salsa20</a> (2008.01.28).
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/// \since Crypto++ 5.6.4
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struct ChaCha8 : public ChaCha_Info<8>, public SymmetricCipherDocumentation
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{
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typedef SymmetricCipherFinal<ConcretePolicyHolder<ChaCha_Policy<8>, AdditiveCipherTemplate<> >, ChaCha_Info<8> > Encryption;
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typedef Encryption Decryption;
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};
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/// \brief ChaCha12 stream cipher
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/// \details Bernstein and ECRYPT's ChaCha is _slightly_ different from the TLS working group's implementation for
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/// cipher suites <tt>TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305_SHA256</tt>,
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/// <tt>TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305_SHA256</tt>, and <tt>TLS_DHE_RSA_WITH_CHACHA20_POLY1305_SHA256</tt>.
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/// \sa <a href="http://cr.yp.to/chacha/chacha-20080128.pdf">ChaCha, a variant of Salsa20</a> (2008.01.28).
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/// \since Crypto++ 5.6.4
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struct ChaCha12 : public ChaCha_Info<12>, public SymmetricCipherDocumentation
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{
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typedef SymmetricCipherFinal<ConcretePolicyHolder<ChaCha_Policy<12>, AdditiveCipherTemplate<> >, ChaCha_Info<12> > Encryption;
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typedef Encryption Decryption;
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};
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/// \brief ChaCha20 stream cipher
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/// \sa <a href="http://cr.yp.to/chacha/chacha-20080128.pdf">ChaCha, a variant of Salsa20</a> (2008.01.28).
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/// \details Bernstein and ECRYPT's ChaCha is _slightly_ different from the TLS working group's implementation for
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/// cipher suites <tt>TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305_SHA256</tt>,
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/// <tt>TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305_SHA256</tt>, and <tt>TLS_DHE_RSA_WITH_CHACHA20_POLY1305_SHA256</tt>.
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/// \since Crypto++ 5.6.4
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struct ChaCha20 : public ChaCha_Info<20>, public SymmetricCipherDocumentation
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{
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typedef SymmetricCipherFinal<ConcretePolicyHolder<ChaCha_Policy<20>, AdditiveCipherTemplate<> >, ChaCha_Info<20> > Encryption;
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typedef Encryption Decryption;
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};
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NAMESPACE_END
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#endif // CRYPTOPP_CHACHA_H
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