Botan  1.10.9
Public Member Functions | List of all members
Botan::ARC4 Class Reference

#include <arc4.h>

Inheritance diagram for Botan::ARC4:
Botan::StreamCipher Botan::SymmetricAlgorithm Botan::Algorithm

Public Member Functions

 ARC4 (size_t skip=0)
 
void cipher (const byte in[], byte out[], size_t length)
 
void cipher1 (byte buf[], size_t len)
 
void clear ()
 
StreamCipherclone () const
 
Key_Length_Specification key_spec () const
 
size_t maximum_keylength () const
 
size_t minimum_keylength () const
 
std::string name () const
 
virtual void set_iv (const byte iv[], size_t iv_len)
 
void set_key (const SymmetricKey &key)
 
void set_key (const byte key[], size_t length)
 
virtual bool valid_iv_length (size_t iv_len) const
 
bool valid_keylength (size_t length) const
 
 ~ARC4 ()
 

Detailed Description

Alleged RC4

Definition at line 19 of file arc4.h.

Constructor & Destructor Documentation

Botan::ARC4::ARC4 ( size_t  skip = 0)
Parameters
skipskip this many initial bytes in the keystream

Definition at line 104 of file arc4.cpp.

References clear().

104  : SKIP(s),
105  state(256),
106  buffer(DEFAULT_BUFFERSIZE)
107  {
108  clear();
109  }
void clear()
Definition: arc4.cpp:94
size_t s
Definition: numthry.cpp:27
Botan::ARC4::~ARC4 ( )
inline

Definition at line 39 of file arc4.h.

39 { clear(); }
void clear()
Definition: arc4.cpp:94

Member Function Documentation

void Botan::ARC4::cipher ( const byte  in[],
byte  out[],
size_t  len 
)
virtual

Encrypt or decrypt a message

Parameters
inthe plaintext
outthe byte array to hold the output, i.e. the ciphertext
lenthe length of both in and out in bytes

Implements Botan::StreamCipher.

Definition at line 17 of file arc4.cpp.

References Botan::MemoryRegion< T >::size(), and Botan::xor_buf().

18  {
19  while(length >= buffer.size() - position)
20  {
21  xor_buf(out, in, &buffer[position], buffer.size() - position);
22  length -= (buffer.size() - position);
23  in += (buffer.size() - position);
24  out += (buffer.size() - position);
25  generate();
26  }
27  xor_buf(out, in, &buffer[position], length);
28  position += length;
29  }
size_t size() const
Definition: secmem.h:29
void xor_buf(byte out[], const byte in[], size_t length)
Definition: xor_buf.h:21
void Botan::StreamCipher::cipher1 ( byte  buf[],
size_t  len 
)
inlineinherited

Encrypt or decrypt a message

Parameters
bufthe plaintext / ciphertext
lenthe length of buf in bytes

Definition at line 34 of file stream_cipher.h.

Referenced by Botan::Lion::decrypt_n(), and Botan::Lion::encrypt_n().

35  { cipher(buf, buf, len); }
virtual void cipher(const byte in[], byte out[], size_t len)=0
void Botan::ARC4::clear ( )
virtual

Zeroize internal state

Implements Botan::Algorithm.

Definition at line 94 of file arc4.cpp.

References Botan::zeroise().

Referenced by ARC4().

95  {
96  zeroise(state);
97  zeroise(buffer);
98  position = X = Y = 0;
99  }
void zeroise(MemoryRegion< T > &vec)
Definition: secmem.h:415
StreamCipher* Botan::ARC4::clone ( ) const
inlinevirtual

Get a new object representing the same algorithm as *this

Implements Botan::StreamCipher.

Definition at line 27 of file arc4.h.

References SKIP.

27 { return new ARC4(SKIP); }
ARC4(size_t skip=0)
Definition: arc4.cpp:104
Key_Length_Specification Botan::ARC4::key_spec ( ) const
inlinevirtual
Returns
object describing limits on key size

Implements Botan::SymmetricAlgorithm.

Definition at line 29 of file arc4.h.

30  {
31  return Key_Length_Specification(1, 256);
32  }
size_t Botan::SymmetricAlgorithm::maximum_keylength ( ) const
inlineinherited
Returns
minimum allowed key length

Definition at line 33 of file sym_algo.h.

34  {
35  return key_spec().maximum_keylength();
36  }
size_t maximum_keylength() const
Definition: key_spec.h:69
virtual Key_Length_Specification key_spec() const =0
size_t Botan::SymmetricAlgorithm::minimum_keylength ( ) const
inlineinherited
Returns
maxmium allowed key length

Definition at line 41 of file sym_algo.h.

42  {
43  return key_spec().minimum_keylength();
44  }
size_t minimum_keylength() const
Definition: key_spec.h:61
virtual Key_Length_Specification key_spec() const =0
std::string Botan::ARC4::name ( ) const
virtual
Returns
name of this algorithm

Implements Botan::Algorithm.

Definition at line 84 of file arc4.cpp.

References Botan::to_string().

85  {
86  if(SKIP == 0) return "ARC4";
87  if(SKIP == 256) return "MARK-4";
88  else return "RC4_skip(" + to_string(SKIP) + ")";
89  }
std::string to_string(u64bit n, size_t min_len)
Definition: parsing.cpp:42
void Botan::StreamCipher::set_iv ( const byte  iv[],
size_t  iv_len 
)
virtualinherited

Resync the cipher using the IV

Parameters
ivthe initialization vector
iv_lenthe length of the IV in bytes

Reimplemented in Botan::WiderWake_41_BE, Botan::CTR_BE, Botan::OFB, Botan::Salsa20, and Botan::Turing.

Definition at line 12 of file stream_cipher.cpp.

References Botan::Algorithm::name().

Referenced by Botan::EAX_Base::set_iv(), and Botan::StreamCipher_Filter::set_iv().

13  {
14  if(iv_len)
15  throw Invalid_Argument("The stream cipher " + name() +
16  " does not support resyncronization");
17  }
std::invalid_argument Invalid_Argument
Definition: exceptn.h:20
virtual std::string name() const =0
void Botan::SymmetricAlgorithm::set_key ( const SymmetricKey key)
inlineinherited
void Botan::SymmetricAlgorithm::set_key ( const byte  key[],
size_t  length 
)
inlineinherited

Set the symmetric key of this object.

Parameters
keythe to be set as a byte array.
lengthin bytes of key param

Definition at line 68 of file sym_algo.h.

69  {
70  if(!valid_keylength(length))
71  throw Invalid_Key_Length(name(), length);
72  key_schedule(key, length);
73  }
bool valid_keylength(size_t length) const
Definition: sym_algo.h:51
virtual std::string name() const =0
bool Botan::StreamCipher::valid_iv_length ( size_t  iv_len) const
virtualinherited
Parameters
iv_lenthe length of the IV in bytes
Returns
if the length is valid for this algorithm

Reimplemented in Botan::WiderWake_41_BE, Botan::CTR_BE, Botan::OFB, Botan::Salsa20, and Botan::Turing.

Definition at line 19 of file stream_cipher.cpp.

20  {
21  return (iv_len == 0);
22  }
bool Botan::SymmetricAlgorithm::valid_keylength ( size_t  length) const
inlineinherited

Check whether a given key length is valid for this algorithm.

Parameters
lengththe key length to be checked.
Returns
true if the key length is valid.

Definition at line 51 of file sym_algo.h.

Referenced by Botan::aont_package(), Botan::aont_unpackage(), Botan::HMAC_RNG::HMAC_RNG(), Botan::Lion::Lion(), Botan::Randpool::Randpool(), and Botan::EAX_Base::valid_keylength().

52  {
53  return key_spec().valid_keylength(length);
54  }
bool valid_keylength(size_t length) const
Definition: key_spec.h:51
virtual Key_Length_Specification key_spec() const =0

The documentation for this class was generated from the following files: