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Hi everyone.. I have written the code for encryption algorithm. It has one user function header file also. Sample code is as shown below... I want return {Pa,C1,C2} in the program to main function. Please help me..
#include <cstdlib>
#include <iostream>
#include <vector>
using namespace std;
#include <math.h>
#include "FiniteFieldElement.hpp"
namespace Cryptography
{
template<int P>
typedef struct {
Cryptography::EllipticCurve<P>::Point Pa;
Cryptography::FiniteFieldElement<P> c1;
Cryptography::FiniteFieldElement<P> c2;
} encrypt_data_t;
class EllipticCurve
{
public:
typedef FiniteFieldElement<P> ffe_t;
class Point
{
friend class EllipticCurve<P>;
typedef FiniteFieldElement<P> ffe_t;
ffe_t x_;
ffe_t y_;
EllipticCurve *ec_;
}
.....
.....
....
...
};
typedef EllipticCurve<P> this_t;
typedef class EllipticCurve<P>::Point point_t;
namespace utils
{
}
using namespace Cryptography;
using namespace utils;
template <int P>
encrypt_data_t<P> my_encrypt()
{
typedef EllipticCurve<263> ec_t;
ec_t myEllipticCurve(1,1);
ec_t::Point Pa = a*G;
ec_t::Point Pk = a*Pb;
ec_t::ffe_t c1( m1*Pk.x() );
ec_t::ffe_t c2( m2*Pk.y() );
cout << "Encrypted message from Alice to Bob = {Pa,c1,c2} = {" << Pa << ", " << c1 << ", " << c2 << "}\n\n";
encrypt_data_t <263> ret;
ret.Pa = Pa;
ret.c1 = c1;
ret.c2 = c2;
return ret;
}
main()
{
int result;
template <int P>
result = encrypt_data_t<P> my_encrypt();
}
"I want to return {Pa,C1,C2} to the main program using structures... I am getting so many errors"
"Please help me with this problem"
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Quote: I am getting so many errors
I would start fixing them (or post them here if you are unable to).
Veni, vidi, vici.
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These are the errors i am getting for the program
Manoj1.cc:25:17: error: template class without a name
Manoj1.cc:25:9: error: template declaration of ‘typedef’
Manoj1.cc:39:44: error: ‘P’ was not declared in this scope
Manoj1.cc:39:45: error: template argument 1 is invalid
Manoj1.cc:47:37: error: ‘EllipticCurve’ is not a template
Manoj1.cc:47:51: error: ‘P’ was not declared in this scope
Manoj1.cc:49:48: error: ‘P’ was not declared in this scope
Manoj1.cc:49:49: error: template argument 1 is invalid
Manoj1.cc:231:41: error: ‘Cryptography::EllipticCurve’ is not a template
Manoj1.cc:231:55: error: ‘P’ was not declared in this scope
Manoj1.cc:243:59: error: ‘Cryptography::EllipticCurve’ is not a template
Manoj1.cc:243:73: error: ‘P’ was not declared in this scope
Manoj1.cc:418:25: error: ‘Cryptography::EllipticCurve’ is not a template
Manoj1.cc:418:39: error: ‘P’ was not declared in this scope
Manoj1.cc:420:31: error: ‘EllipticCurve’ is not a template
Manoj1.cc:420:45: error: ‘P’ was not declared in this scope
Manoj1.cc:521:36: error: ‘P’ was not declared in this scope
Manoj1.cc:521:37: error: template argument 1 is invalid
Manoj1.cc:525:36: error: ‘P’ was not declared in this scope
Manoj1.cc:525:37: error: template argument 1 is invalid
Manoj1.cc:533:64: error: ‘Cryptography::EllipticCurve’ is not a template
Manoj1.cc:549:40: error: ‘P’ was not declared in this scope
Manoj1.cc:549:41: error: template argument 1 is invalid
Manoj1.cc:551:40: error: ‘P’ was not declared in this scope
Manoj1.cc:551:41: error: template argument 1 is invalid
Manoj1.cc: In member function ‘Cryptography::EllipticCurve::Point Cryptography::EllipticCurve::Point::scalarMultiply(int, const Cryptography::EllipticCurve::Point&)’:
Manoj1.cc:90:51: error: call of overloaded ‘Point(int, int, Cryptography::EllipticCurve&)’ is ambiguous
Manoj1.cc:90:51: note: candidates are:
Manoj1.cc:243:21: note: Cryptography::EllipticCurve::Point::Point(const ffe_t&, const ffe_t&, Cryptography::EllipticCurve&)
Manoj1.cc:231:21: note: Cryptography::EllipticCurve::Point::Point(int, int, Cryptography::EllipticCurve&)
Manoj1.cc: In member function ‘void Cryptography::EllipticCurve::Point::add(Cryptography::EllipticCurve::Point::ffe_t, Cryptography::EllipticCurve::Point::ffe_t, Cryptography::EllipticCurve::Point::ffe_t, Cryptography::EllipticCurve::Point::ffe_t, Cryptography::EllipticCurve::Point::ffe_t&, Cryptography::EllipticCurve::Point::ffe_t&) const’:
Manoj1.cc:179:40: error: request for member ‘i’ in ‘x1’, which is of non-class type ‘Cryptography::EllipticCurve::Point::ffe_t {aka int}’
Manoj1.cc:179:47: error: request for member ‘i’ in ‘x1’, which is of non-class type ‘Cryptography::EllipticCurve::Point::ffe_t {aka int}’
Manoj1.cc: In function ‘Cryptography::EllipticCurve::Point Cryptography::operator+(const Cryptography::EllipticCurve::Point&, const Cryptography::EllipticCurve::Point&)’:
Manoj1.cc:364:52: error: call of overloaded ‘Point(Cryptography::EllipticCurve::Point::ffe_t&, Cryptography::EllipticCurve::Point::ffe_t&, Cryptography::EllipticCurve&)’ is ambiguous
Manoj1.cc:364:52: note: candidates are:
Manoj1.cc:243:21: note: Cryptography::EllipticCurve::Point::Point(const ffe_t&, const ffe_t&, Cryptography::EllipticCurve&)
Manoj1.cc:231:21: note: Cryptography::EllipticCurve::Point::Point(int, int, Cryptography::EllipticCurve&)
Manoj1.cc: In member function ‘void Cryptography::EllipticCurve::CalculatePoints()’:
Manoj1.cc:447:31: error: ‘P’ was not declared in this scope
Manoj1.cc:457:25: error: ‘x_val’ was not declared in this scope
Manoj1.cc:457:50: error: request for member ‘i’ in ‘((Cryptography::EllipticCurve*)this)->Cryptography::EllipticCurve::a_’, which is of non-class type ‘int’
Manoj1.cc:457:63: error: request for member ‘i’ in ‘((Cryptography::EllipticCurve*)this)->Cryptography::EllipticCurve::b_’, which is of non-class type ‘int’
Manoj1.cc:459:25: error: ‘y_val’ was not declared in this scope
Manoj1.cc:473:34: error: ‘x_val’ was not declared in this scope
Manoj1.cc:473:46: error: ‘y_val’ was not declared in this scope
Manoj1.cc:477:67: error: call of overloaded ‘Point(int&, int&, Cryptography::EllipticCurve&)’ is ambiguous
Manoj1.cc:477:67: note: candidates are:
Manoj1.cc:243:21: note: Cryptography::EllipticCurve::Point::Point(const ffe_t&, const ffe_t&, Cryptography::EllipticCurve&)
Manoj1.cc:231:21: note: Cryptography::EllipticCurve::Point::Point(int, int, Cryptography::EllipticCurve&)
Manoj1.cc: In member function ‘int Cryptography::EllipticCurve::Degree() const’:
Manoj1.cc:517:49: error: ‘P’ was not declared in this scope
Manoj1.cc: At global scope:
Manoj1.cc:561:22: error: expected nested-name-specifier before ‘EllipticCurve’
Manoj1.cc:561:35: error: expected initializer before ‘<’ token
Manoj1.cc:567:49: error: ‘Cryptography::EllipticCurve’ is not a template
Manoj1.cc: In function ‘std::ostream& Cryptography::operator<<(std::ostream&, const Cryptography::EllipticCurve&)’:
Manoj1.cc:583:35: error: request for member ‘i’ in ‘EllipticCurve.b_’, which is of non-class type ‘const int’
Manoj1.cc: At global scope:
Manoj1.cc:603:34: error: expected initializer before ‘<’ token
Manoj1.cc:685:1: error: ‘Cryptography::EllipticCurve’ is not a template
Manoj1.cc:685:23: error: expected initializer before ‘my_encrypt’
Manoj1.cc:856:11: error: ‘::main’ must return ‘int’
Manoj1.cc: In function ‘int main()’:
Manoj1.cc:859:3: error: a template declaration cannot appear at block scope
Manoj1.cc:861:2: error: expected ‘;’ before ‘}’ token
The complete program is
#include <cstdlib>
#include <iostream>
#include <vector>
using namespace std;
#include <math.h>
#include "FiniteFieldElement.hpp"
namespace Cryptography
{
template<int p="">
typedef struct {
Cryptography::EllipticCurve::Point Pa;
Cryptography::FiniteFieldElement c1;
Cryptography::FiniteFieldElement c2;
} encrypt_data_t;
class EllipticCurve
{
public:
typedef FiniteFieldElement ffe_t;
class Point
{
friend class EllipticCurve ;
typedef FiniteFieldElement ffe_t;
ffe_t x_;
ffe_t y_;
EllipticCurve *ec_;
void addDouble(int m, Point& acc)
{
if ( m > 0 )
{
Point r = acc;
for ( int n=0; n < m; ++n )
{
r += r; // doubling step
}
acc = r;
}
}
Point scalarMultiply(int k, const Point& a)
{
Point acc = a;
Point res = Point(0,0,*ec_);
int i = 0, j = 0;
int b = k;
while( b )
{
if ( b & 1 )
{
addDouble(i-j,acc);
res += acc;
j = i;
}
b >>= 1;
++i;
}
return res;
}
void add(ffe_t x1, ffe_t y1, ffe_t x2, ffe_t y2, ffe_t & xR, ffe_t & yR) const
{
if ( x1 == 0 && y1 == 0 )
{
xR = x2;
yR = y2;
return;
}
if ( x2 == 0 && y2 == 0 )
{
xR = x1;
yR = y1;
return;
}
if ( y1 == -y2 )
{
xR = yR = 0;
return;
}
// the additions
ffe_t s;
if ( x1 == x2 && y1 == y2 )
{
//2P
s = (3*(x1.i()*x1.i()) + ec_->a()) / (2*y1);
xR = ((s*s) - 2*x1);
}
else
{
//P+Q
s = (y1 - y2) / (x1 - x2);
xR = ((s*s) - x1 - x2);
}
if ( s != 0 )
{
yR = (-y1 + s*(x1 - xR));
}
else
{
xR = yR = 0;
}
}
Point(int x, int y)
: x_(x),
y_(y),
ec_(0)
{}
Point(int x, int y, EllipticCurve & EllipticCurve)
: x_(x),
y_(y),
ec_(&EllipticCurve)
{}
Point(const ffe_t& x, const ffe_t& y, EllipticCurve & EllipticCurve)
: x_(x),
y_(y),
ec_(&EllipticCurve)
{}
public:
static Point ONE;
// copy ctor
Point(const Point& rhs)
{
x_ = rhs.x_;
y_ = rhs.y_;
ec_ = rhs.ec_;
}
// assignment
Point& operator=(const Point& rhs)
{
x_ = rhs.x_;
y_ = rhs.y_;
ec_ = rhs.ec_;
return *this;
}
// access x component as element of Fp
ffe_t x() const { return x_; }
// access y component as element of Fp
ffe_t y() const { return y_; }
unsigned int Order(unsigned int maxPeriod = ~0) const
{
Point r = *this;
unsigned int n = 0;
while( r.x_ != 0 && r.y_ != 0 )
{
++n;
r += *this;
if ( n > maxPeriod ) break;
}
return n;
}
// negate
Point operator-()
{
return Point(x_,-y_);
}
// ==
friend bool operator==(const Point& lhs, const Point& rhs)
{
return (lhs.ec_ == rhs.ec_) && (lhs.x_ == rhs.x_) && (lhs.y_ == rhs.y_);
}
// !=
friend bool operator!=(const Point& lhs, const Point& rhs)
{
return (lhs.ec_ != rhs.ec_) || (lhs.x_ != rhs.x_) || (lhs.y_ != rhs.y_);
}
// a + b
friend Point operator+(const Point& lhs, const Point& rhs)
{
ffe_t xR, yR;
lhs.add(lhs.x_,lhs.y_,rhs.x_,rhs.y_,xR,yR);
return Point(xR,yR,*lhs.ec_);
}
// a * int
friend Point operator*(int k, const Point& rhs)
{
return Point(rhs).operator*=(k);
}
// +=
Point& operator+=(const Point& rhs)
{
add(x_,y_,rhs.x_,rhs.y_,x_,y_);
return *this;
}
// a *= int
Point& operator*=(int k)
{
return (*this = scalarMultiply(k,*this));
}
// ostream handler: print this point
friend ostream& operator <<(ostream& os, const Point& p)
{
return (os << "(" << p.x_ << ", " << p.y_ << ")");
}
};
// ==================================================== EllipticCurve impl
typedef EllipticCurve this_t;
typedef class EllipticCurve ::Point point_t;
// ctor
// Initialize EC as y^2 = x^3 + ax + b
EllipticCurve(int a, int b)
: a_(a),
b_(b),
m_table_(),
table_filled_(false)
{
}
void CalculatePoints()
{
int x_val[P];
int y_val[P];
for ( int n = 0; n < P; ++n )
{
int nsq = n*n;
x_val[n] = ((n*nsq) + a_.i() * n + b_.i()) % P;
y_val[n] = nsq % P;
}
for ( int n = 0; n < P; ++n )
{
for ( int m = 0; m < P; ++m )
{
if ( x_val[n] == y_val[m] )
{
m_table_.push_back(Point(n,m,*this));
}
}
}
table_filled_ = true;
}
// get a point (group element) on the curve
Point operator[](int n)
{
if ( !table_filled_ )
{
CalculatePoints();
}
return m_table_[n];
}
// number of elements in this group
size_t Size() const { return m_table_.size(); }
// the degree P of this EC
int Degree() const { return P; }
// the parameter a (as an element of Fp)
FiniteFieldElement a() const { return a_; }
// the paramter b (as an element of Fp)
FiniteFieldElement b() const { return b_; }
// ostream handler: print this curve in human readable form
template<int t="">
friend ostream& operator <<(ostream& os, const EllipticCurve<t>& EllipticCurve);
// print all the elements of the EC group
ostream& PrintTable(ostream &os, int columns=4);
private:
typedef std::vector<point> m_table_t;
m_table_t m_table_; // table of points
FiniteFieldElement a_; // paramter a of the EC equation
FiniteFieldElement b_; // parameter b of the EC equation
bool table_filled_; // true if the table has been calculated
};
template<int t="">
typename EllipticCurve<t>::Point EllipticCurve<t>::Point::ONE(0,0);
template<int t="">
ostream& operator <<(ostream& os, const EllipticCurve<t>& EllipticCurve)
{
os << "y^2 mod " << T << " = (x^3" << showpos;
if ( EllipticCurve.a_ != 0 )
{
os << EllipticCurve.a_ << "x";
}
if ( EllipticCurve.b_.i() != 0 )
{
os << EllipticCurve.b_;
}
os << noshowpos << ") mod " << T;
return os;
}
template<int p="">
ostream& EllipticCurve ::PrintTable(ostream &os, int columns)
{
if ( table_filled_ )
{
int col = 0;
typename EllipticCurve ::m_table_t::iterator iter = m_table_.begin();
for ( ; iter!=m_table_.end(); ++iter )
{
os << "(" << (*iter).x_.i() << ", " << (*iter).y_.i() << ") ";
if ( ++col > columns )
{
os << "\n";
col = 0;
}
}
}
else
{
os << "EllipticCurve, F_" << P;
}
return os;
}
}
namespace utils
{
float frand()
{
static float norm = 1.0f / (float)RAND_MAX;
return (float)rand()*norm;
}
int irand(int min, int max)
{
return min+(int)(frand()*(float)(max-min));
}
}
using namespace Cryptography;
using namespace utils;
template <int p="">
EllipticCurve ec_t my_encrypt()
{
// template <int p="">
//encrypt_data_t my_encrypt();
typedef EllipticCurve<263> ec_t;
ec_t myEllipticCurve(1,1);
cout << "A little Elliptic Curve cryptography example\nby Jarl Ostensen, 2007\n\n";
// print out a little info and test some properties
cout << "The elliptic curve: " << myEllipticCurve << "\n";
myEllipticCurve.CalculatePoints();
cout << "\nPoints on the curve (i.e. the group elements):\n";
myEllipticCurve.PrintTable(cout,5);
cout << "\n\n";
ec_t::Point P = myEllipticCurve[2];
cout << "some point P = " << P << ", 2P = " << (P+P) << "\n";
ec_t::Point Q = myEllipticCurve[3];
cout << "some point Q = " << Q << ", P+Q = " << (P+Q) << "\n";
ec_t::Point R = P;
R += Q;
cout << "P += Q = " << R << "\n";
R = P;
R += R;
cout << "P += P = 2P = " << R << "\n";
cout << "\nEC message encryption example\n===============================================\n\n";
ec_t::Point G = myEllipticCurve[0];
while( (G.y() == 0 || G.x() == 0) || (G.Order()<2) )
{
int n = (int)(frand()*myEllipticCurve.Size());
G = myEllipticCurve[n];
}
cout << "G = " << G << ", order(G) is " << G.Order() << "\n";
// Alice
int a = irand(1,myEllipticCurve.Degree()-1);
ec_t::Point Pa = a*G; // public key
cout << "Alice' public key Pa = " << a << "*" << G << " = " << Pa << endl;
// Bob
int b = irand(1,myEllipticCurve.Degree()-1);;
ec_t::Point Pb = b*G; // public key
cout << "Bob's public key Pb = " << b << "*" << G << " = " << Pb << endl;
// Jane, the eavesdropper
int j = irand(1,myEllipticCurve.Degree()-1);;
ec_t::Point Pj = j*G;
cout << "Jane's public key Pj = " << j << "*" << G << " = " << Pj << endl;
cout << "\n\n";
int m1 = 19;
int m2 = 72;
cout << "Plain text message from Alice to Bob: (" << m1 << ", " << m2 << ")\n";
// encrypt using Bob`s key
ec_t::Point Pk = a*Pb;
ec_t::ffe_t c1( m1*Pk.x() );
ec_t::ffe_t c2( m2*Pk.y() );
// encrypted message is: Pa,c1,c2
cout << "Encrypted message from Alice to Bob = {Pa,c1,c2} = {" << Pa << ", " << c1 << ", " << c2 << "}\n\n";
encrypt_data_t <263> ret;
ret.Pa = Pa;
ret.c1 = c1;
ret.c2 = c2;
return ret;
// Bob now decrypts Alice`s message, using her public key and his session integer "b" which was also used to generate his public key
Pk = b*Pa;
ec_t::ffe_t m1d = c1/Pk.x();
ec_t::ffe_t m2d = c2/Pk.y();
cout << "\tBob's decrypted message from Alice = (" << m1d << ", " << m2d << ")" << endl;
// Jane intercepts the message and tries to decrypt it using her key
Pk = j*Pa;
m1d = c1/Pk.x();
m2d = c2/Pk.y();
cout << "\nJane's decrypted message from Alice = (" << m1d << ", " << m2d << ")" << endl;
cout << endl;
}
void main()
{
int result;
template <int p="">
result = encrypt_data_t my_encrypt();
}
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I think that confirms my comment to you about the use of namespaces and templates.
Use the best guess
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Get rid of all your templates and namespaces, they serve no purpose.
Use the best guess
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Templates and namespaces are very important for my program.
I have not posted the full code there...
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Manoj7390 wrote: Templates and namespaces are very important for my program.
That is most unlikely, and looking at what you have posted you are not using them for any good reason. You should get the code working first without the use of either, and then add them (if they are really necessary) at a later stage.
Use the best guess
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Starting at the bottom, your main function doesn't make sense - it's one huge syntax error. Even with all the context and the realisation what this is about (encryption), it's almost impossible to guess what it should do.
Obviously you're not familiar with template syntax. Your attempt to invoke a templated function using a templated type is a syntactical mess. Your data structure definitions contain errors related to incomplete or improper template syntax. For that reason, and because you don't really use or need those template parameters, you should really forget about them!
Since you claim you do need the template, use a const instead: in most cases, where people think they need a template, a global/static definition works just as well:
const int P = 263;
Start with your struct definition:
struct encrypt_data_t {
EllipticCurve<P>::Point Pa;
FiniteFieldElement<P> c1;
FiniteFieldElement<P> c2;
};
There: no typedef required, no template parameters required. Also, since the definition is within your namespace, no need to explicitely add the prefix "Cryptography::".
Next, remove any remaining template parameter definition line in your code: if you always used P as the template parameter name, everything should compile after removing the template <argument list>.
Last: fix your main(). I have no idea what your intention is, but you do call a function that returns a struct, and apparently try to assign that struct to an int. That doesn't make sense. Fix it, or at least remove that assignment, so you can find out and fix any remaining syntax errors. Besides, you omitted the return type for main() (always int), and your main didn't return a value. Both should be listed as errors or at the very least as warnings by your compiler. But it's possible your compiler didn't get that far due to it's inability to resolve previous spaghetti template syntax.
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I want to return {Pa,c1,c2} from this program to another main() function. Please help me out.
#include <cstdlib>
#include <iostream>
#include <vector>
using std:: cout;
using std:: cin;
using std:: endl;
using namespace std;
#include <math.h>
#include "FiniteFieldElement.hpp"
namespace Cryptography
{
template<int P>
class EllipticCurve
{
public:
typedef FiniteFieldElement<P> ffe_t;
class Point
{
friend class EllipticCurve<P>;
typedef FiniteFieldElement<P> ffe_t;
ffe_t x_;
ffe_t y_;
EllipticCurve *ec_;
void addDouble(int m, Point& acc)
{
if ( m > 0 )
{
Point r = acc;
for ( int n=0; n < m; ++n )
{
r += r;
}
acc = r;
}
}
Point scalarMultiply(int k, const Point& a)
{
Point acc = a;
Point res = Point(0,0,*ec_);
int i = 0, j = 0;
int b = k;
while( b )
{
if ( b & 1 )
{
addDouble(i-j,acc);
res += acc;
j = i;
}
b >>= 1;
++i;
}
return res;
}
void add(ffe_t x1, ffe_t y1, ffe_t x2, ffe_t y2, ffe_t & xR, ffe_t & yR) const
{
if ( x1 == 0 && y1 == 0 )
{
xR = x2;
yR = y2;
return;
}
if ( x2 == 0 && y2 == 0 )
{
xR = x1;
yR = y1;
return;
}
if ( y1 == -y2 )
{
xR = yR = 0;
return;
}
ffe_t s;
if ( x1 == x2 && y1 == y2 )
{
s = (3*(x1.i()*x1.i()) + ec_->a()) / (2*y1);
xR = ((s*s) - 2*x1);
}
else
{
s = (y1 - y2) / (x1 - x2);
xR = ((s*s) - x1 - x2);
}
if ( s != 0 )
{
yR = (-y1 + s*(x1 - xR));
}
else
{
xR = yR = 0;
}
}
Point(int x, int y)
: x_(x),
y_(y),
ec_(0)
{}
Point(int x, int y, EllipticCurve<P> & EllipticCurve)
: x_(x),
y_(y),
ec_(&EllipticCurve)
{}
Point(const ffe_t& x, const ffe_t& y, EllipticCurve<P> & EllipticCurve)
: x_(x),
y_(y),
ec_(&EllipticCurve)
{}
public:
static Point ONE;
Point(const Point& rhs)
{
x_ = rhs.x_;
y_ = rhs.y_;
ec_ = rhs.ec_;
}
Point& operator=(const Point& rhs)
{
x_ = rhs.x_;
y_ = rhs.y_;
ec_ = rhs.ec_;
return *this;
}
ffe_t x() const { return x_; }
ffe_t y() const { return y_; }
unsigned int Order(unsigned int maxPeriod = ~0) const
{
Point r = *this;
unsigned int n = 0;
while( r.x_ != 0 && r.y_ != 0 )
{
++n;
r += *this;
if ( n > maxPeriod ) break;
}
return n;
}
Point operator-()
{
return Point(x_,-y_);
}
friend bool operator==(const Point& lhs, const Point& rhs)
{
return (lhs.ec_ == rhs.ec_) && (lhs.x_ == rhs.x_) && (lhs.y_ == rhs.y_);
}
friend bool operator!=(const Point& lhs, const Point& rhs)
{
return (lhs.ec_ != rhs.ec_) || (lhs.x_ != rhs.x_) || (lhs.y_ != rhs.y_);
}
friend Point operator+(const Point& lhs, const Point& rhs)
{
ffe_t xR, yR;
lhs.add(lhs.x_,lhs.y_,rhs.x_,rhs.y_,xR,yR);
return Point(xR,yR,*lhs.ec_);
}
friend Point operator*(int k, const Point& rhs)
{
return Point(rhs).operator*=(k);
}
Point& operator+=(const Point& rhs)
{
add(x_,y_,rhs.x_,rhs.y_,x_,y_);
return *this;
}
Point& operator*=(int k)
{
return (*this = scalarMultiply(k,*this));
}
friend ostream& operator <<(ostream& os, const Point& p)
{
return (os << "(" << p.x_ << ", " << p.y_ << ")");
}
};
typedef EllipticCurve<P> this_t;
typedef class EllipticCurve<P>::Point point_t;
EllipticCurve(int a, int b)
: a_(a),
b_(b),
m_table_(),
table_filled_(false)
{
}
void CalculatePoints()
{
int x_val[P];
int y_val[P];
for ( int n = 0; n < P; ++n )
{
int nsq = n*n;
x_val[n] = ((n*nsq) + a_.i() * n + b_.i()) % P;
y_val[n] = nsq % P;
}
for ( int n = 0; n < P; ++n )
{
for ( int m = 0; m < P; ++m )
{
if ( x_val[n] == y_val[m] )
{
m_table_.push_back(Point(n,m,*this));
}
}
}
table_filled_ = true;
}
Point operator[](int n)
{
if ( !table_filled_ )
{
CalculatePoints();
}
return m_table_[n];
}
size_t Size() const { return m_table_.size(); }
int Degree() const { return P; }
FiniteFieldElement<P> a() const { return a_; }
FiniteFieldElement<P> b() const { return b_; }
template<int T>
friend ostream& operator <<(ostream& os, const EllipticCurve<T>& EllipticCurve);
ostream& PrintTable(ostream &os, int columns=4);
private:
typedef std::vector<Point> m_table_t;
m_table_t m_table_;
FiniteFieldElement<P> a_;
FiniteFieldElement<P> b_;
bool table_filled_;
};
template<int T>
typename EllipticCurve<T>::Point EllipticCurve<T>::Point::ONE(0,0);
template<int T>
ostream& operator <<(ostream& os, const EllipticCurve<T>& EllipticCurve)
{
os << "y^2 mod " << T << " = (x^3" << showpos;
if ( EllipticCurve.a_ != 0 )
{
os << EllipticCurve.a_ << "x";
}
if ( EllipticCurve.b_.i() != 0 )
{
os << EllipticCurve.b_;
}
os << noshowpos << ") mod " << T;
return os;
}
template<int P>
ostream& EllipticCurve<P>::PrintTable(ostream &os, int columns)
{
if ( table_filled_ )
{
int col = 0;
typename EllipticCurve<P>::m_table_t::iterator iter = m_table_.begin();
for ( ; iter!=m_table_.end(); ++iter )
{
os << "(" << (*iter).x_.i() << ", " << (*iter).y_.i() << ") ";
if ( ++col > columns )
{
os << "\n";
col = 0;
}
}
}
else
{
os << "EllipticCurve, F_" << P;
}
return os;
}
}
namespace utils
{
float frand()
{
static float norm = 1.0f / (float)RAND_MAX;
return (float)rand()*norm;
}
int irand(int min, int max)
{
return min+(int)(frand()*(float)(max-min));
}
}
using namespace Cryptography;
using namespace utils;
int main(int argc, char *argv[])
{
typedef EllipticCurve<263> ec_t;
ec_t myEllipticCurve(1,1);
cout << "A little Elliptic Curve cryptography example\nby Jarl Ostensen, 2007\n\n";
cout << "The elliptic curve: " << myEllipticCurve << "\n";
myEllipticCurve.CalculatePoints();
cout << "\nPoints on the curve (i.e. the group elements):\n";
myEllipticCurve.PrintTable(cout,5);
cout << "\n\n";
ec_t::Point P = myEllipticCurve[2];
cout << "some point P = " << P << ", 2P = " << (P+P) << "\n";
ec_t::Point Q = myEllipticCurve[3];
cout << "some point Q = " << Q << ", P+Q = " << (P+Q) << "\n";
ec_t::Point R = P;
R += Q;
cout << "P += Q = " << R << "\n";
R = P;
R += R;
cout << "P += P = 2P = " << R << "\n";
cout << "\nEC message encryption example\n===============================================\n\n";
ec_t::Point G = myEllipticCurve[0];
while( (G.y() == 0 || G.x() == 0) || (G.Order()<2) )
{
int n = (int)(frand()*myEllipticCurve.Size());
G = myEllipticCurve[n];
}
cout << "G = " << G << ", order(G) is " << G.Order() << "\n";
int a = irand(1,myEllipticCurve.Degree()-1);
ec_t::Point Pa = a*G;
cout << "Alice' public key Pa = " << a << "*" << G << " = " << Pa << endl;
int b = irand(1,myEllipticCurve.Degree()-1);;
ec_t::Point Pb = b*G;
cout << "Bob's public key Pb = " << b << "*" << G << " = " << Pb << endl;
int j = irand(1,myEllipticCurve.Degree()-1);;
ec_t::Point Pj = j*G;
cout << "Jane's public key Pj = " << j << "*" << G << " = " << Pj << endl;
cout << "\n\n";
int m1,m2;
cout << "Enter two message\n"<< endl;
cin >> m1;
cin >> m2;
cout << "Plain text message from Alice to Bob: (" << m1 << ", " << m2 << ")\n";
ec_t::Point Pk = a*Pb;
ec_t::ffe_t c1( m1*Pk.x() );
ec_t::ffe_t c2( m2*Pk.y() );
cout << "Encrypted message from Alice to Bob = {Pa,c1,c2} = {" << Pa << ", " << c1 << ", " << c2 << "}\n\n";
Pk = b*Pa;
ec_t::ffe_t m1d = c1/Pk.x();
ec_t::ffe_t m2d = c2/Pk.y();
cout << "\tBob's decrypted message from Alice = (" << m1d << ", " << m2d << ")" << endl;
Pk = j*Pa;
m1d = c1/Pk.x();
m2d = c2/Pk.y();
cout << "\nJane's decrypted message from Alice = (" << m1d << ", " << m2d << ")" << endl;
cout << endl;
}
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Without the declaration of the class FiniteFieldElement, and without the error messages, I can't help you. I've successfully compiled that code by using the following dummy declaration:
template <int P>
class FiniteFieldElement {
public:
FiniteFieldElement(){}
FiniteFieldElement(int){}
int i() const {return 0;}
operator int() const {return 0;}
};
This means that either there is a problem with the actual class declaration, or you are not using it correctly.
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The code is working fine. I need to return those three variables i.e. {Pa,c1,c2} from that program to another main program. What should i have to do. I have used structure for that but its not working. Please tell how to return a three user defined data type to the main function
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Manoj7390 wrote: The code is working fine.
Now, that is news!
From your original posting:
Manoj7390 wrote: <layer>I am getting so many errors
May be you should have been clearer from the start about this...
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There can only be one int main(). You have to separate the code that does the calculations from the code that inquires the input. You have plenty of functions that pass values around, so I don't see why there should be a problem passing these values via a function interface.
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how to return those values using structure or by declaring class
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Change the struct definition to
template<int P> struct encrypt_data_t {
typename Cryptography::EllipticCurve<P>::Point Pa;
FiniteFieldElement<P> c1;
FiniteFieldElement<P> c2;
} ;
Then call this function like this:
int main(...) {
const int MY_P = 263;
...
encrypt_data_t<MY_P> result = my_encrypt<MY_P>();
...
}
Of course, you also have to fix your function code - the code you posted does not declare half the variables it uses.
Or you could just skip that structure and instead pass these values back by reference[^]:
template <int P>
void my_encrypt(typename Cryptography::EllipticCurve<P>::Point& Pa,
FiniteFieldElement<P>& c1, FiniteFieldElement<P>& c2) {
...
}
int main(...) {
const int MY_P = 263;
typename Cryptography::EllipticCurve<MY_P>::Point Pa;
FiniteFieldElement<MY_P> c1;
FiniteFieldElement<MY_P> c2;
my_encrypt(Pa, c1, c2);
}
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I need to develop a tool which peroform all operation on USB drive attached on other computer.
Application needs to perform all operation which can be perform by local compter.
Please guide me how to start and wnat things I need to lookinto?
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Could you clarify which operation you have to perform?
What is USB drive on other computer/local computer?
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Once a USB drive is attached to another computer, the drivers will install on the other computer as well.
On this being done and said, you can then access the contents of the USB drive just like any other remote drive.
Not sure what do you mean by "all operation". the above is answered assuming you are querying for copy/paste and other basic functionalities.
You talk about Being HUMAN. I have it in my name
AnsHUMAN
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Hi
I am getting the following compiler error in that the compiler can't find filea.cpp
I am using visual studio 2010 professional
The file appear in my project -> source files
When I right click in each of the .cpp source files and compile them Separately they each compile
cleanly including filea.cpp
Is there anyway to tell where this compiler error is coming from
Thanks
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Why is it referring to the file with two elipses (i.e., parent folder) notation?
"One man's wage rise is another man's price increase." - Harold Wilson
"Fireproof doesn't mean the fire will never come. It means when the fire comes that you will be able to withstand it." - Michael Simmons
"Show me a community that obeys the Ten Commandments and I'll show you a less crowded prison system." - Anonymous
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Don't know here is the actual build output
1>------ Rebuild All started: Project: TunTap32, Configuration: Release x64 ------
1>Build started 6/19/2013 11:45:32 AM.
1>_PrepareForClean:
1> Deleting file "x64\Release\TunTap32.lastbuildstate".
1>InitializeBuildStatus:
1> Touching "x64\Release\TunTap32.unsuccessfulbuild".
1>ClCompile:
1> StdAfx.cpp
1> fishtrace.cpp
1> TT32api.cpp
1> TTAdapter.cpp
1> TunTap.cpp
1> TunTap32.cpp
1> fishtrace.cpp
1>c1xx : fatal error C1083: Cannot open source file: '..\fishtrace.cpp': No such file or directory
1> Generating Code...
1>
1>Build FAILED.
1>
1>Time Elapsed 00:00:03.20
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Try removing (but not deleting) the file from your project, and then adding it back in. You should familiarise yourself with rules of projects as this sort of issue can crop up unexpectedly. Open the project file in Notepad (but be careful not to corrupt it) and see how the rules are put together.
Use the best guess
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Look in the project's VCPROJ file for a reference to each of these files. See if you notice anything different about fishtrace.cpp.
"One man's wage rise is another man's price increase." - Harold Wilson
"Fireproof doesn't mean the fire will never come. It means when the fire comes that you will be able to withstand it." - Michael Simmons
"Show me a community that obeys the Ten Commandments and I'll show you a less crowded prison system." - Anonymous
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Hi,
I am using DirectShow to Play / Pause / Stop and Capture Video files. But Capturing and playing of video files is simple. I want to Implement HD Video recording in my project.
Anybody have any idea of how to Implement HD Video Capturing using DirectShow.?
Or Apart from DirectShow, is there any other method to Implement HD Video recording in MFC.
Regards,
Mbatra
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