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

#include <ecdsa.h>

Inheritance diagram for Botan::ECDSA_Verification_Operation:
Botan::PK_Ops::Verification

Public Member Functions

 ECDSA_Verification_Operation (const ECDSA_PublicKey &ecdsa)
 
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 SecureVector< byteverify_mr (const byte[], size_t)
 
bool with_recovery () const
 

Detailed Description

ECDSA verification operation

Definition at line 117 of file ecdsa.h.

Constructor & Destructor Documentation

Botan::ECDSA_Verification_Operation::ECDSA_Verification_Operation ( const ECDSA_PublicKey ecdsa)

Definition at line 65 of file ecdsa.cpp.

65  :
66  base_point(ecdsa.domain().get_base_point()),
67  public_point(ecdsa.public_point()),
68  order(ecdsa.domain().get_order())
69  {
70  }

Member Function Documentation

size_t Botan::ECDSA_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 124 of file ecdsa.h.

124 { return order.bits(); }
size_t bits() const
Definition: bigint.cpp:253
size_t Botan::ECDSA_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 123 of file ecdsa.h.

123 { return order.bytes(); }
size_t bytes() const
Definition: bigint.cpp:245
size_t Botan::ECDSA_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 122 of file ecdsa.h.

122 { return 2; }
bool Botan::ECDSA_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 72 of file ecdsa.cpp.

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

74  {
75  if(sig_len != order.bytes()*2)
76  return false;
77 
78  BigInt e(msg, msg_len);
79 
80  BigInt r(sig, sig_len / 2);
81  BigInt s(sig + sig_len / 2, sig_len / 2);
82 
83  if(r <= 0 || r >= order || s <= 0 || s >= order)
84  return false;
85 
86  BigInt w = inverse_mod(s, order);
87 
88  PointGFp R = w * multi_exponentiate(base_point, e,
89  public_point, r);
90 
91  if(R.is_zero())
92  return false;
93 
94  return (R.get_affine_x() % order == r);
95  }
BigInt inverse_mod(const BigInt &n, const BigInt &mod)
Definition: numthry.cpp:202
BigInt r
Definition: numthry.cpp:26
PointGFp multi_exponentiate(const PointGFp &p1, const BigInt &z1, const PointGFp &p2, const BigInt &z2)
Definition: point_gfp.cpp:257
size_t s
Definition: numthry.cpp:27
size_t bytes() const
Definition: bigint.cpp:245
virtual SecureVector<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.

135  {
136  throw Invalid_State("Message recovery not supported");
137  }
bool Botan::ECDSA_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 126 of file ecdsa.h.

126 { return false; }

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