Botan::NR_Signature_Operation Class Reference

#include <nr.h>

Inheritance diagram for Botan::NR_Signature_Operation:

Public Member Functions
size_t	max_input_bits () const
size_t	message_part_size () const
size_t	message_parts () const
	NR_Signature_Operation (const NR_PrivateKey &nr)
SecureVector< byte >	sign (const byte msg[], size_t msg_len, RandomNumberGenerator &rng)

Detailed Description

Nyberg-Rueppel signature operation

Definition at line 61 of file nr.h.

Constructor & Destructor Documentation

NR_Signature_Operation()

Botan::NR_Signature_Operation::NR_Signature_Operation

(

const NR_PrivateKey &

nr

)

Definition at line 74 of file nr.cpp.

                                                                      :
   q(nr.group_q()),
   x(nr.get_x()),
   powermod_g_p(nr.group_g(), nr.group_p()),
   mod_q(nr.group_q())
   {
   }

Referenced by Botan::Core_Engine::get_signature_op().

Member Function Documentation

max_input_bits()

size_t Botan::NR_Signature_Operation::max_input_bits ( ) const

inlinevirtual

Get the maximum message size in bits supported by this public key.

Returns

maximum message in bits

Implements Botan::PK_Ops::Signature.

Definition at line 68 of file nr.h.

{ return (q.bits() - 1); }

message_part_size()

size_t Botan::NR_Signature_Operation::message_part_size ( ) const

inlinevirtual

Find out the message part size supported by this scheme/key.

Returns

size of the message parts

Reimplemented from Botan::PK_Ops::Signature.

Definition at line 67 of file nr.h.

{ return q.bytes(); }

message_parts()

size_t Botan::NR_Signature_Operation::message_parts ( ) const

inlinevirtual

Find out the number of message parts supported by this scheme.

Returns

number of message parts

Reimplemented from Botan::PK_Ops::Signature.

Definition at line 66 of file nr.h.

{ return 2; }

sign()

SecureVector< byte > Botan::NR_Signature_Operation::sign ( const byte msg[], size_t msg_len, RandomNumberGenerator & rng )

virtual

Implements Botan::PK_Ops::Signature.

Definition at line 83 of file nr.cpp.

   {
   rng.add_entropy(msg, msg_len);
 
   BigInt f(msg, msg_len);
 
   if(f >= q)
      throw Invalid_Argument("NR_Signature_Operation: Input is out of range");
 
   BigInt c, d;
 
   while(c == 0)
      {
      BigInt k;
      do
         k.randomize(rng, q.bits());
      while(k >= q);
 
      c = mod_q.reduce(powermod_g_p(k) + f);
      d = mod_q.reduce(k - x * c);
      }
 
   SecureVector<byte> output(2*q.bytes());
   c.binary_encode(&output[output.size() / 2 - c.bytes()]);
   d.binary_encode(&output[output.size() - d.bytes()]);
   return output;
   }

References Botan::RandomNumberGenerator::add_entropy(), Botan::BigInt::binary_encode(), Botan::BigInt::bytes(), Botan::BigInt::randomize(), and Botan::MemoryRegion< T >::size().

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

• src/pubkey/nr/nr.h
• src/pubkey/nr/nr.cpp