Botan::Comb4P Class Reference

#include <comb4p.h>

Inheritance diagram for Botan::Comb4P:

Public Member Functions
void	clear ()
HashFunction *	clone () const
	Comb4P (HashFunction *h1, HashFunction *h2)
SecureVector< byte >	final ()
void	final (byte out[])
size_t	hash_block_size () const
std::string	name () const
size_t	output_length () const
SecureVector< byte >	process (const byte in[], size_t length)
SecureVector< byte >	process (const MemoryRegion< byte > &in)
SecureVector< byte >	process (const std::string &in)
void	update (byte in)
void	update (const byte in[], size_t length)
void	update (const MemoryRegion< byte > &in)
void	update (const std::string &str)
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

Comb4P()

Botan::Comb4P::Comb4P	(	HashFunction *	h1,
		HashFunction *	h2 )

Parameters

h1	the first hash
h2	the second hash

Definition at line 37 of file comb4p.cpp.

                                                 :
   hash1(h1), hash2(h2)
   {
   if(hash1->name() == hash2->name())
      throw std::invalid_argument("Comb4P: Must use two distinct hashes");
 
   if(hash1->output_length() != hash2->output_length())
      throw std::invalid_argument("Comb4P: Incompatible hashes " +
                                  hash1->name() + " and " +
                                  hash2->name());
 
   clear();
   }

References clear().

Referenced by clone(), and Botan::Core_Engine::find_hash().

~Comb4P()

Botan::Comb4P::~Comb4P ( )

inline

Definition at line 28 of file comb4p.h.

{ delete hash1; delete hash2; }

Member Function Documentation

clear()

void Botan::Comb4P::clear ( )

virtual

Zeroize internal state

Implements Botan::Algorithm.

Definition at line 63 of file comb4p.cpp.

   {
   hash1->clear();
   hash2->clear();
 
   // Prep for processing next message, if any
   hash1->update(0);
   hash2->update(0);
   }

Referenced by Comb4P().

clone()

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.

         {
         return new Comb4P(hash1->clone(), hash2->clone());
         }

References Comb4P().

final() [1/2]

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.

         {
         SecureVector<byte> output(output_length());
         final_result(&output[0]);
         return output;
         }

References output_length().

final() [2/2]

void Botan::Buffered_Computation::final ( byte out[] )

inlineinherited

Complete the computation and retrieve the final result.

Parameters

out	The byte array to be filled with the result. Must be of length output_length()

Definition at line 80 of file buf_comp.h.

{ final_result(out); }

Referenced by Botan::X942_PRF::derive(), Botan::HandshakeHash::final(), and Botan::HandshakeHash::final_ssl3().

hash_block_size()

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.

   {
   if(hash1->hash_block_size() == hash2->hash_block_size())
      return hash1->hash_block_size();
 
   /*
   * Return LCM of the block sizes? This would probably be OK for
   * HMAC, which is the main thing relying on knowing the block size.
   */
   return 0;
   }

name()

std::string Botan::Comb4P::name ( ) const

inlinevirtual

Returns

name of this algorithm

Implements Botan::Algorithm.

Definition at line 42 of file comb4p.h.

         {
         return "Comb4P(" + hash1->name() + "," + hash2->name() + ")";
         }

output_length()

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.

         {
         return hash1->output_length() + hash2->output_length();
         }

process() [1/3]

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

in	the input to process as a byte array
length	the length of the byte array

Returns

the result of the call to final()

Definition at line 101 of file buf_comp.h.

         {
         add_data(in, length);
         return final();
         }

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

process() [2/3]

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

in	the input to process

Returns

the result of the call to final()

Definition at line 113 of file buf_comp.h.

         {
         add_data(&in[0], in.size());
         return final();
         }

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

process() [3/3]

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

in	the input to process as a string

Returns

the result of the call to final()

Definition at line 125 of file buf_comp.h.

         {
         update(in);
         return final();
         }

References update().

update() [1/4]

void Botan::Buffered_Computation::update ( byte in )

inlineinherited

Process a single byte.

Parameters

in	the byte to process

Definition at line 72 of file buf_comp.h.

{ add_data(&in, 1); }

update() [2/4]

void Botan::Buffered_Computation::update ( const byte in[], size_t length )

inlineinherited

Add new input to process.

Parameters

in	the input to process as a byte array
length	of param in in bytes

Definition at line 33 of file buf_comp.h.

{ add_data(in, length); }

Referenced by Botan::X942_PRF::derive(), Botan::HandshakeHash::final(), Botan::HandshakeHash::final_ssl3(), process(), and Botan::EAX_Base::start_msg().

update() [3/4]

void Botan::Buffered_Computation::update ( const MemoryRegion< byte > & in )

inlineinherited

Add new input to process.

Parameters

in	the input to process as a MemoryRegion

Definition at line 39 of file buf_comp.h.

         {
         add_data(&in[0], in.size());
         }

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

update() [4/4]

void Botan::Buffered_Computation::update ( const std::string & str )

inlineinherited

Add new input to process.

Parameters

str	the 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.

         {
         add_data(reinterpret_cast<const byte*>(str.data()), str.size());
         }

update_be()

template<typename T>

void Botan::Buffered_Computation::update_be ( const T in )

inlineinherited

Add an integer in big-endian order

Parameters

in

the value

Definition at line 48 of file buf_comp.h.

         {
         for(size_t i = 0; i != sizeof(T); ++i)
            {
            byte b = get_byte(i, in);
            add_data(&b, 1);
            }
         }

References Botan::get_byte().

---

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

• src/hash/comb4p/comb4p.h
• src/hash/comb4p/comb4p.cpp