Crypto++  8.2
Free C++ class library of cryptographic schemes
salsa.h
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1 // salsa.h - originally written and placed in the public domain by Wei Dai
2 
3 /// \file salsa.h
4 /// \brief Classes for Salsa and Salsa20 stream ciphers
5 
6 #ifndef CRYPTOPP_SALSA_H
7 #define CRYPTOPP_SALSA_H
8 
9 #include "strciphr.h"
10 #include "secblock.h"
11 
12 // Clang 3.3 integrated assembler crash on Linux. Clang 3.4 due to compiler
13 // error with .intel_syntax, http://llvm.org/bugs/show_bug.cgi?id=24232
14 #if CRYPTOPP_BOOL_X32 || defined(CRYPTOPP_DISABLE_MIXED_ASM)
15 # define CRYPTOPP_DISABLE_SALSA_ASM 1
16 #endif
17 
18 NAMESPACE_BEGIN(CryptoPP)
19 
20 /// \brief Salsa20 core transform
21 /// \param data the data to transform
22 /// \param rounds the number of rounds
23 /// \details Several algorithms, like CryptoBox and Scrypt, require access to
24 /// the core Salsa20 transform. The current Crypto++ implementation does not
25 /// lend itself to disgorging the Salsa20 cipher from the Salsa20 core transform.
26 /// Instead Salsa20_Core is provided with customary accelerations.
27 void Salsa20_Core(word32* data, unsigned int rounds);
28 
29 /// \brief Salsa20 stream cipher information
30 struct Salsa20_Info : public VariableKeyLength<32, 16, 32, 16, SimpleKeyingInterface::UNIQUE_IV, 8>
31 {
32  static std::string StaticAlgorithmName() {return "Salsa20";}
33 };
34 
35 /// \brief Salsa20 stream cipher operation
36 class CRYPTOPP_NO_VTABLE Salsa20_Policy : public AdditiveCipherConcretePolicy<word32, 16>
37 {
38 protected:
39  Salsa20_Policy() : m_rounds(ROUNDS) {}
40  void CipherSetKey(const NameValuePairs &params, const byte *key, size_t length);
41  void OperateKeystream(KeystreamOperation operation, byte *output, const byte *input, size_t iterationCount);
42  void CipherResynchronize(byte *keystreamBuffer, const byte *IV, size_t length);
43  bool CipherIsRandomAccess() const {return true;}
44  void SeekToIteration(lword iterationCount);
45 
46 #if (CRYPTOPP_BOOL_X86 || CRYPTOPP_BOOL_X32 || CRYPTOPP_BOOL_X64)
47  unsigned int GetAlignment() const;
48  unsigned int GetOptimalBlockSize() const;
49 #endif
50 
51  std::string AlgorithmProvider() const;
52 
53  CRYPTOPP_CONSTANT(ROUNDS = 20) // Default rounds
55  int m_rounds;
56 };
57 
58 /// \brief Salsa20 stream cipher
59 /// \details Salsa20 provides a variable number of rounds: 8, 12 or 20. The default number of rounds is 20.
60 /// \sa <a href="http://www.cryptolounge.org/wiki/XSalsa20">XSalsa20</a>
62 {
64  typedef Encryption Decryption;
65 };
66 
67 /// \brief XSalsa20 stream cipher information
68 struct XSalsa20_Info : public FixedKeyLength<32, SimpleKeyingInterface::UNIQUE_IV, 24>
69 {
70  static std::string StaticAlgorithmName() {return "XSalsa20";}
71 };
72 
73 /// \brief XSalsa20 stream cipher operation
74 class CRYPTOPP_NO_VTABLE XSalsa20_Policy : public Salsa20_Policy
75 {
76 public:
77  void CipherSetKey(const NameValuePairs &params, const byte *key, size_t length);
78  void CipherResynchronize(byte *keystreamBuffer, const byte *IV, size_t length);
79 
80 protected:
82 };
83 
84 /// \brief XSalsa20 stream cipher
85 /// \details XSalsa20 provides a variable number of rounds: 8, 12 or 20. The default number of rounds is 20.
86 /// \sa <a href="http://www.cryptolounge.org/wiki/XSalsa20">XSalsa20</a>
88 {
90  typedef Encryption Decryption;
91 };
92 
93 NAMESPACE_END
94 
95 #endif
Inherited by keyed algorithms with fixed key length.
Definition: seckey.h:124
Base class for additive stream ciphers.
Definition: strciphr.h:201
XSalsa20 stream cipher information.
Definition: salsa.h:68
unsigned int GetAlignment() const
Provides data alignment requirements.
Definition: strciphr.h:221
Salsa20 stream cipher information.
Definition: salsa.h:30
Classes and functions for secure memory allocations.
XSalsa20 stream cipher.
Definition: salsa.h:87
XSalsa20 stream cipher operation.
Definition: salsa.h:74
void Salsa20_Core(word32 *data, unsigned int rounds)
Salsa20 core transform.
Definition: salsa.cpp:51
virtual void OperateKeystream(KeystreamOperation operation, byte *output, const byte *input, size_t iterationCount)=0
Operates the keystream.
Inherited by keyed algorithms with variable key length.
Definition: seckey.h:165
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:413
KeystreamOperation
Keystream operation flags.
Definition: strciphr.h:88
Salsa20 stream cipher.
Definition: salsa.h:61
Crypto++ library namespace.
SymmetricCipher implementation.
Definition: strciphr.h:673
Salsa20 stream cipher operation.
Definition: salsa.h:36
Interface for retrieving values given their names.
Definition: cryptlib.h:293