Botan: Botan::GOST_3410_Verification_Operation Class Reference

#include <gost_3410.h>

Inheritance diagram for Botan::GOST_3410_Verification_Operation:

Public Member Functions
	GOST_3410_Verification_Operation (const GOST_3410_PublicKey &gost)

size_t	max_input_bits () const

size_t	message_part_size () const

size_t	message_parts () const

bool	verify (const byte msg[], size_t msg_len, const byte sig[], size_t sig_len)

virtual secure_vector< byte >	verify_mr (const byte[], size_t)

bool	with_recovery () const

Detailed Description

GOST-34.10 verification operation

Definition at line 118 of file gost_3410.h.

Constructor & Destructor Documentation

Botan::GOST_3410_Verification_Operation::GOST_3410_Verification_Operation ( const GOST_3410_PublicKey & gost )

Definition at line 137 of file gost_3410.cpp.

                                                                                                   :
    base_point(gost.domain().get_base_point()),
    public_point(gost.public_point()),
    order(gost.domain().get_order())
    {

   }

Member Function Documentation

size_t Botan::GOST_3410_Verification_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::Verification.

Definition at line 125 of file gost_3410.h.

125 { return order.bits(); }

size_t Botan::GOST_3410_Verification_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::Verification.

Definition at line 124 of file gost_3410.h.

124 { return order.bytes(); }

size_t Botan::GOST_3410_Verification_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::Verification.

Definition at line 123 of file gost_3410.h.

123 { return 2; }

bool Botan::GOST_3410_Verification_Operation::verify	(	const byte	msg[],
		size_t	msg_len,
		const byte	sig[],
		size_t	sig_len
	)

virtual

Reimplemented from Botan::PK_Ops::Verification.

Definition at line 144 of file gost_3410.cpp.

References Botan::BigInt::bytes(), Botan::PointGFp::get_affine_x(), Botan::inverse_mod(), Botan::PointGFp::is_zero(), Botan::multi_exponentiate(), r, and s.

    {
    if(sig_len != order.bytes()*2)
       return false;
 
    BigInt e = decode_le(msg, msg_len);
 
    BigInt s(sig, sig_len / 2);
    BigInt r(sig + sig_len / 2, sig_len / 2);
 
    if(r <= 0 || r >= order || s <= 0 || s >= order)
       return false;
 
    e %= order;
    if(e == 0)
       e = 1;
 
    BigInt v = inverse_mod(e, order);
 
    BigInt z1 = (s*v) % order;
    BigInt z2 = (-r*v) % order;
 
    PointGFp R = multi_exponentiate(base_point, z1,
                                    public_point, z2);
 
    if(R.is_zero())
      return false;
 
    return (R.get_affine_x() == r);
    }

virtual secure_vector<byte> Botan::PK_Ops::Verification::verify_mr	(	const byte	[],
		size_t
	)

inlinevirtualinherited

Reimplemented in Botan::RSA_Public_Operation, Botan::RW_Verification_Operation, and Botan::NR_Verification_Operation.

Definition at line 133 of file pk_ops.h.

          {
          throw Invalid_State("Message recovery not supported");
          }

bool Botan::GOST_3410_Verification_Operation::with_recovery ( ) const

inlinevirtual

Returns: boolean specifying if this key type supports message recovery and thus if you need to call verify() or verify_mr()

Implements Botan::PK_Ops::Verification.

Definition at line 127 of file gost_3410.h.

127 { return false; }

Public Member Functions

Detailed Description

Constructor & Destructor Documentation

Member Function Documentation