Botan  1.10.9
Public Member Functions | List of all members
Botan::Comb4P Class Reference

#include <comb4p.h>

Inheritance diagram for Botan::Comb4P:
Botan::HashFunction Botan::Buffered_Computation Botan::Algorithm

Public Member Functions

void clear ()
 
HashFunctionclone () const
 
 Comb4P (HashFunction *h1, HashFunction *h2)
 
void final (byte out[])
 
SecureVector< bytefinal ()
 
size_t hash_block_size () const
 
std::string name () const
 
size_t output_length () const
 
SecureVector< byteprocess (const byte in[], size_t length)
 
SecureVector< byteprocess (const MemoryRegion< byte > &in)
 
SecureVector< byteprocess (const std::string &in)
 
void update (const byte in[], size_t length)
 
void update (const MemoryRegion< byte > &in)
 
void update (const std::string &str)
 
void update (byte in)
 
template<typename T >
void update_be (const T in)
 
 ~Comb4P ()
 

Detailed Description

Combines two hash functions using a Feistel scheme. Described in "On the Security of Hash Function Combiners", Anja Lehmann

Definition at line 19 of file comb4p.h.

Constructor & Destructor Documentation

Botan::Comb4P::Comb4P ( HashFunction h1,
HashFunction h2 
)
Parameters
h1the first hash
h2the second hash

Definition at line 37 of file comb4p.cpp.

References clear(), Botan::Algorithm::name(), and Botan::Buffered_Computation::output_length().

37  :
38  hash1(h1), hash2(h2)
39  {
40  if(hash1->name() == hash2->name())
41  throw std::invalid_argument("Comb4P: Must use two distinct hashes");
42 
43  if(hash1->output_length() != hash2->output_length())
44  throw std::invalid_argument("Comb4P: Incompatible hashes " +
45  hash1->name() + " and " +
46  hash2->name());
47 
48  clear();
49  }
void clear()
Definition: comb4p.cpp:63
virtual std::string name() const =0
virtual size_t output_length() const =0
Botan::Comb4P::~Comb4P ( )
inline

Definition at line 28 of file comb4p.h.

28 { delete hash1; delete hash2; }

Member Function Documentation

void Botan::Comb4P::clear ( )
virtual

Zeroize internal state

Implements Botan::Algorithm.

Definition at line 63 of file comb4p.cpp.

References Botan::Algorithm::clear(), and Botan::Buffered_Computation::update().

Referenced by Comb4P().

64  {
65  hash1->clear();
66  hash2->clear();
67 
68  // Prep for processing next message, if any
69  hash1->update(0);
70  hash2->update(0);
71  }
virtual void clear()=0
void update(const byte in[], size_t length)
Definition: buf_comp.h:33
HashFunction* Botan::Comb4P::clone ( ) const
inlinevirtual

Get a new object representing the same algorithm as *this

Implements Botan::HashFunction.

Definition at line 37 of file comb4p.h.

38  {
39  return new Comb4P(hash1->clone(), hash2->clone());
40  }
Comb4P(HashFunction *h1, HashFunction *h2)
Definition: comb4p.cpp:37
virtual HashFunction * clone() const =0
void Botan::Buffered_Computation::final ( byte  out[])
inlineinherited
SecureVector<byte> Botan::Buffered_Computation::final ( )
inlineinherited

Complete the computation and retrieve the final result.

Returns
SecureVector holding the result

Definition at line 87 of file buf_comp.h.

88  {
89  SecureVector<byte> output(output_length());
90  final_result(&output[0]);
91  return output;
92  }
virtual size_t output_length() const =0
size_t Botan::Comb4P::hash_block_size ( ) const
virtual

The hash block size as defined for this algorithm

Reimplemented from Botan::HashFunction.

Definition at line 51 of file comb4p.cpp.

References Botan::HashFunction::hash_block_size().

52  {
53  if(hash1->hash_block_size() == hash2->hash_block_size())
54  return hash1->hash_block_size();
55 
56  /*
57  * Return LCM of the block sizes? This would probably be OK for
58  * HMAC, which is the main thing relying on knowing the block size.
59  */
60  return 0;
61  }
virtual size_t hash_block_size() const
Definition: hash.h:32
std::string Botan::Comb4P::name ( ) const
inlinevirtual
Returns
name of this algorithm

Implements Botan::Algorithm.

Definition at line 42 of file comb4p.h.

43  {
44  return "Comb4P(" + hash1->name() + "," + hash2->name() + ")";
45  }
virtual std::string name() const =0
size_t Botan::Comb4P::output_length ( ) const
inlinevirtual
Returns
length of the output of this function in bytes

Implements Botan::Buffered_Computation.

Definition at line 32 of file comb4p.h.

33  {
34  return hash1->output_length() + hash2->output_length();
35  }
virtual size_t output_length() const =0
SecureVector<byte> Botan::Buffered_Computation::process ( const byte  in[],
size_t  length 
)
inlineinherited

Update and finalize computation. Does the same as calling update() and final() consecutively.

Parameters
inthe input to process as a byte array
lengththe length of the byte array
Returns
the result of the call to final()

Definition at line 101 of file buf_comp.h.

Referenced by Botan::Randpool::add_entropy(), Botan::EME1::EME1(), Botan::RTSS_Share::split(), and Botan::Cert_Extension::Subject_Key_ID::Subject_Key_ID().

102  {
103  add_data(in, length);
104  return final();
105  }
SecureVector<byte> Botan::Buffered_Computation::process ( const MemoryRegion< byte > &  in)
inlineinherited

Update and finalize computation. Does the same as calling update() and final() consecutively.

Parameters
inthe input to process
Returns
the result of the call to final()

Definition at line 113 of file buf_comp.h.

References Botan::MemoryRegion< T >::size().

114  {
115  add_data(&in[0], in.size());
116  return final();
117  }
size_t size() const
Definition: secmem.h:29
SecureVector<byte> Botan::Buffered_Computation::process ( const std::string &  in)
inlineinherited

Update and finalize computation. Does the same as calling update() and final() consecutively.

Parameters
inthe input to process as a string
Returns
the result of the call to final()

Definition at line 125 of file buf_comp.h.

126  {
127  update(in);
128  return final();
129  }
void update(const byte in[], size_t length)
Definition: buf_comp.h:33
void Botan::Buffered_Computation::update ( const byte  in[],
size_t  length 
)
inlineinherited
void Botan::Buffered_Computation::update ( const MemoryRegion< byte > &  in)
inlineinherited

Add new input to process.

Parameters
inthe input to process as a MemoryRegion

Definition at line 39 of file buf_comp.h.

References Botan::MemoryRegion< T >::size().

40  {
41  add_data(&in[0], in.size());
42  }
size_t size() const
Definition: secmem.h:29
void Botan::Buffered_Computation::update ( const std::string &  str)
inlineinherited

Add new input to process.

Parameters
strthe input to process as a std::string. Will be interpreted as a byte array based on the strings encoding.

Definition at line 63 of file buf_comp.h.

64  {
65  add_data(reinterpret_cast<const byte*>(str.data()), str.size());
66  }
void Botan::Buffered_Computation::update ( byte  in)
inlineinherited

Process a single byte.

Parameters
inthe byte to process

Definition at line 72 of file buf_comp.h.

72 { add_data(&in, 1); }
template<typename T >
void Botan::Buffered_Computation::update_be ( const T  in)
inlineinherited

Add an integer in big-endian order

Parameters
inthe value

Definition at line 48 of file buf_comp.h.

References Botan::get_byte().

Referenced by Botan::KDF2::derive(), Botan::PKCS5_PBKDF2::derive_key(), Botan::Record_Reader::get_record(), and Botan::MGF1::mask().

49  {
50  for(size_t i = 0; i != sizeof(T); ++i)
51  {
52  byte b = get_byte(i, in);
53  add_data(&b, 1);
54  }
55  }
byte get_byte(size_t byte_num, T input)
Definition: get_byte.h:21
unsigned char byte
Definition: types.h:22

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