Crypto++  5.6.5
Free C++ class library of cryptographic schemes
chacha.h
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1 // chacha.h - written and placed in the public domain by Jeffrey Walton.
2 // Copyright assigned to the Crypto++ project.
3 // Based on Wei Dai's Salsa20 and Bernstein's reference ChaCha
4 // family implementation at http://cr.yp.to/chacha.html.
5 
6 //! \file chacha.h
7 //! \brief Classes for ChaCha8, ChaCha12 and ChaCha20 stream ciphers
8 //! \details Crypto++ provides Bernstein and ECRYPT's ChaCha from <a href="http://cr.yp.to/chacha/chacha-20080128.pdf">ChaCha,
9 //! a variant of Salsa20</a> (2008.01.28). Bernstein's implementation is _slightly_ different from the TLS working group's
10 //! implementation for cipher suites <tt>TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305_SHA256</tt>,
11 //! <tt>TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305_SHA256</tt>, and <tt>TLS_DHE_RSA_WITH_CHACHA20_POLY1305_SHA256</tt>.
12 //! \since Crypto++ 5.6.4
13 
14 #ifndef CRYPTOPP_CHACHA_H
15 #define CRYPTOPP_CHACHA_H
16 
17 #include "strciphr.h"
18 #include "secblock.h"
19 
20 NAMESPACE_BEGIN(CryptoPP)
21 
22 //! \class ChaCha_Info
23 //! \brief ChaCha stream cipher information
24 //! \since Crypto++ 5.6.4
25 template <unsigned int R>
26 struct ChaCha_Info : public VariableKeyLength<32, 16, 32, 16, SimpleKeyingInterface::UNIQUE_IV, 8>, public FixedRounds<R>
27 {
28  CRYPTOPP_CONSTEXPR static const char *StaticAlgorithmName() {
29  return (R==8?"ChaCha8":(R==12?"ChaCha12":(R==20?"ChaCha20":"ChaCha")));
30  }
31 };
32 
33 //! \class ChaCha_Policy
34 //! \brief ChaCha stream cipher implementation
35 //! \since Crypto++ 5.6.4
36 template <unsigned int R>
37 class CRYPTOPP_NO_VTABLE ChaCha_Policy : public AdditiveCipherConcretePolicy<word32, 16>
38 {
39 protected:
40  CRYPTOPP_CONSTANT(ROUNDS=FixedRounds<R>::ROUNDS)
41 
42  void CipherSetKey(const NameValuePairs &params, const byte *key, size_t length);
43  void OperateKeystream(KeystreamOperation operation, byte *output, const byte *input, size_t iterationCount);
44  void CipherResynchronize(byte *keystreamBuffer, const byte *IV, size_t length);
45  bool CipherIsRandomAccess() const {return false;} // TODO
46  void SeekToIteration(lword iterationCount);
47  unsigned int GetAlignment() const;
48  unsigned int GetOptimalBlockSize() const;
49 
51 };
52 
53 //! \class ChaCha8
54 //! \brief ChaCha8 stream cipher
55 //! \sa <a href="http://cr.yp.to/chacha/chacha-20080128.pdf">ChaCha, a variant of Salsa20</a> (2008.01.28).
56 //! \since Crypto++ 5.6.4
58 {
60  typedef Encryption Decryption;
61 };
62 
63 //! \class ChaCha12
64 //! \brief ChaCha12 stream cipher
65 //! \details Bernstein and ECRYPT's ChaCha is _slightly_ different from the TLS working group's implementation for
66 //! cipher suites <tt>TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305_SHA256</tt>,
67 //! <tt>TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305_SHA256</tt>, and <tt>TLS_DHE_RSA_WITH_CHACHA20_POLY1305_SHA256</tt>.
68 //! \sa <a href="http://cr.yp.to/chacha/chacha-20080128.pdf">ChaCha, a variant of Salsa20</a> (2008.01.28).
69 //! \since Crypto++ 5.6.4
71 {
73  typedef Encryption Decryption;
74 };
75 
76 //! \class ChaCha20
77 //! \brief ChaCha20 stream cipher
78 //! \sa <a href="http://cr.yp.to/chacha/chacha-20080128.pdf">ChaCha, a variant of Salsa20</a> (2008.01.28).
79 //! \details Bernstein and ECRYPT's ChaCha is _slightly_ different from the TLS working group's implementation for
80 //! cipher suites <tt>TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305_SHA256</tt>,
81 //! <tt>TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305_SHA256</tt>, and <tt>TLS_DHE_RSA_WITH_CHACHA20_POLY1305_SHA256</tt>.
82 //! \since Crypto++ 5.6.4
84 {
86  typedef Encryption Decryption;
87 };
88 
89 NAMESPACE_END
90 
91 #endif // CRYPTOPP_CHACHA_H
ChaCha stream cipher information.
Definition: chacha.h:26
unsigned int GetAlignment() const
Provides data alignment requirements.
Definition: strciphr.h:198
Base class for additive stream ciphers.
Definition: strciphr.h:188
ChaCha8 stream cipher.
Definition: chacha.h:57
Classes and functions for secure memory allocations.
ChaCha stream cipher implementation.
Definition: chacha.h:37
virtual void OperateKeystream(KeystreamOperation operation, byte *output, const byte *input, size_t iterationCount)=0
Operates the keystream.
Interface for algorithms that take byte strings as keys.
Definition: cryptlib.h:529
Inherited by algorithms with fixed number of rounds.
Definition: seckey.h:47
Inherited by keyed algorithms with variable key length.
Definition: seckey.h:177
const char * IV()
ConstByteArrayParameter, also accepts const byte * for backwards compatibility.
Definition: argnames.h:21
Classes for implementing stream ciphers.
Provides Encryption and Decryption typedefs used by derived classes to implement a symmetric cipher...
Definition: seckey.h:439
KeystreamOperation
Keystream operation flags.
Definition: strciphr.h:92
SymmetricCipher implementation.
Definition: strciphr.h:584
Base class for additive stream ciphers with SymmetricCipher interface.
Definition: strciphr.h:269
ChaCha12 stream cipher.
Definition: chacha.h:70
Interface for retrieving values given their names.
Definition: cryptlib.h:282
ChaCha20 stream cipher.
Definition: chacha.h:83