what's wrong in this RSA why the results of encryption/decryption are different?
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enter code herethis is p,q,n,phi,e,d and there is no any error in code and all the arthimitic operations are correct and I am sure, but what probably I mistake here?
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click 'encrypt
ee = Convert.ToDouble(txtE.Text)
n = Convert.ToDouble(txtN.Text)
m = Convert.ToDouble(txtMessage.Text)
txtCipher.Text = powermod(m, ee, n)
End Sub
Private Sub Button2_Click(sender As Object, e As EventArgs) Handles Button2.Click 'decrypt
dd = Convert.ToDouble(txtD.Text)
n = Convert.ToDouble(txtN.Text)
c = Convert.ToDouble(txtCipher.Text)
txtMessageRecovery.Text = powermod(c, dd, n)
End Sub
Public Function powermod(base As Double, exponent As Double, modulus As Double) As Double
If base < 1 Or exponent < 0 Or modulus < 1 Then Return -1
Dim result As Double = 1
While (exponent > 0)
If ((exponent Mod 2) = 1) Then
result = (result * base) Mod modulus
End If
base = (base * base) Mod modulus
exponent = Floor(exponent / 2)
End While
Return result
End Function
the numbers in this image
vb.net
asked Nov 23 '18 at 14:21
Burier EliaBurier Elia
61
add a comment |
0
enter code herethis is p,q,n,phi,e,d and there is no any error in code and all the arthimitic operations are correct and I am sure, but what probably I mistake here?
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click 'encrypt
ee = Convert.ToDouble(txtE.Text)
n = Convert.ToDouble(txtN.Text)
m = Convert.ToDouble(txtMessage.Text)
txtCipher.Text = powermod(m, ee, n)
End Sub
Private Sub Button2_Click(sender As Object, e As EventArgs) Handles Button2.Click 'decrypt
dd = Convert.ToDouble(txtD.Text)
n = Convert.ToDouble(txtN.Text)
c = Convert.ToDouble(txtCipher.Text)
txtMessageRecovery.Text = powermod(c, dd, n)
End Sub
Public Function powermod(base As Double, exponent As Double, modulus As Double) As Double
If base < 1 Or exponent < 0 Or modulus < 1 Then Return -1
Dim result As Double = 1
While (exponent > 0)
If ((exponent Mod 2) = 1) Then
result = (result * base) Mod modulus
End If
base = (base * base) Mod modulus
exponent = Floor(exponent / 2)
End While
Return result
End Function
the numbers in this image
vb.net
asked Nov 23 '18 at 14:21
Burier EliaBurier Elia
61
2
The double type is not accurate enough to do this correctly, integer math is required. Use the System.Security.Cryptography namespace.
– Hans Passant
Nov 23 '18 at 15:05
thanks hans, but what's mean by integer math?, do you mean Integer data type? @HansPassant
– Burier Elia
Nov 23 '18 at 16:08
2
Consider googling "floating point math vs integer math" to find stuff to help you understand the difference.
– Hans Passant
Nov 23 '18 at 16:10
@HansPassant I use double because it doesn't have maximum range
– Burier Elia
Nov 23 '18 at 16:14
2
It trades range for precision. Double has only 53 bits to represent the value, the simplest RSA encryption key needs 330 bits. System.Security.Cryptograph has the code that can manipulate that many bits.
– Hans Passant
Nov 23 '18 at 16:23
add a comment |
0
0
0
enter code herethis is p,q,n,phi,e,d and there is no any error in code and all the arthimitic operations are correct and I am sure, but what probably I mistake here?
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click 'encrypt
ee = Convert.ToDouble(txtE.Text)
n = Convert.ToDouble(txtN.Text)
m = Convert.ToDouble(txtMessage.Text)
txtCipher.Text = powermod(m, ee, n)
End Sub
Private Sub Button2_Click(sender As Object, e As EventArgs) Handles Button2.Click 'decrypt
dd = Convert.ToDouble(txtD.Text)
n = Convert.ToDouble(txtN.Text)
c = Convert.ToDouble(txtCipher.Text)
txtMessageRecovery.Text = powermod(c, dd, n)
End Sub
Public Function powermod(base As Double, exponent As Double, modulus As Double) As Double
If base < 1 Or exponent < 0 Or modulus < 1 Then Return -1
Dim result As Double = 1
While (exponent > 0)
If ((exponent Mod 2) = 1) Then
result = (result * base) Mod modulus
End If
base = (base * base) Mod modulus
exponent = Floor(exponent / 2)
End While
Return result
End Function
the numbers in this image
vb.net
asked Nov 23 '18 at 14:21
Burier EliaBurier Elia
61
enter code herethis is p,q,n,phi,e,d and there is no any error in code and all the arthimitic operations are correct and I am sure, but what probably I mistake here?
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click 'encrypt
ee = Convert.ToDouble(txtE.Text)
n = Convert.ToDouble(txtN.Text)
m = Convert.ToDouble(txtMessage.Text)
txtCipher.Text = powermod(m, ee, n)
End Sub
Private Sub Button2_Click(sender As Object, e As EventArgs) Handles Button2.Click 'decrypt
dd = Convert.ToDouble(txtD.Text)
n = Convert.ToDouble(txtN.Text)
c = Convert.ToDouble(txtCipher.Text)
txtMessageRecovery.Text = powermod(c, dd, n)
End Sub
Public Function powermod(base As Double, exponent As Double, modulus As Double) As Double
If base < 1 Or exponent < 0 Or modulus < 1 Then Return -1
Dim result As Double = 1
While (exponent > 0)
If ((exponent Mod 2) = 1) Then
result = (result * base) Mod modulus
End If
base = (base * base) Mod modulus
exponent = Floor(exponent / 2)
End While
Return result
End Function
the numbers in this image
vb.net
vb.net
asked Nov 23 '18 at 14:21
Burier EliaBurier Elia
61
asked Nov 23 '18 at 14:21
Burier EliaBurier Elia
61
edited Nov 23 '18 at 14:39
Burier Elia
asked Nov 23 '18 at 14:21
Burier EliaBurier Elia
61
asked Nov 23 '18 at 14:21
Burier EliaBurier Elia
61
asked Nov 23 '18 at 14:21
Burier EliaBurier Elia
61
61
2
The double type is not accurate enough to do this correctly, integer math is required. Use the System.Security.Cryptography namespace.
– Hans Passant
Nov 23 '18 at 15:05
thanks hans, but what's mean by integer math?, do you mean Integer data type? @HansPassant
– Burier Elia
Nov 23 '18 at 16:08
2
Consider googling "floating point math vs integer math" to find stuff to help you understand the difference.
– Hans Passant
Nov 23 '18 at 16:10
@HansPassant I use double because it doesn't have maximum range
– Burier Elia
Nov 23 '18 at 16:14
2
It trades range for precision. Double has only 53 bits to represent the value, the simplest RSA encryption key needs 330 bits. System.Security.Cryptograph has the code that can manipulate that many bits.
– Hans Passant
Nov 23 '18 at 16:23
add a comment |
2
The double type is not accurate enough to do this correctly, integer math is required. Use the System.Security.Cryptography namespace.
– Hans Passant
Nov 23 '18 at 15:05
thanks hans, but what's mean by integer math?, do you mean Integer data type? @HansPassant
– Burier Elia
Nov 23 '18 at 16:08
2
Consider googling "floating point math vs integer math" to find stuff to help you understand the difference.
– Hans Passant
Nov 23 '18 at 16:10
@HansPassant I use double because it doesn't have maximum range
– Burier Elia
Nov 23 '18 at 16:14
2
It trades range for precision. Double has only 53 bits to represent the value, the simplest RSA encryption key needs 330 bits. System.Security.Cryptograph has the code that can manipulate that many bits.
– Hans Passant
Nov 23 '18 at 16:23
2
2
The double type is not accurate enough to do this correctly, integer math is required. Use the System.Security.Cryptography namespace.
– Hans Passant
Nov 23 '18 at 15:05
The double type is not accurate enough to do this correctly, integer math is required. Use the System.Security.Cryptography namespace.
– Hans Passant
Nov 23 '18 at 15:05
thanks hans, but what's mean by integer math?, do you mean Integer data type? @HansPassant
– Burier Elia
Nov 23 '18 at 16:08
thanks hans, but what's mean by integer math?, do you mean Integer data type? @HansPassant
– Burier Elia
Nov 23 '18 at 16:08
2
2
Consider googling "floating point math vs integer math" to find stuff to help you understand the difference.
– Hans Passant
Nov 23 '18 at 16:10
Consider googling "floating point math vs integer math" to find stuff to help you understand the difference.
– Hans Passant
Nov 23 '18 at 16:10
@HansPassant I use double because it doesn't have maximum range
– Burier Elia
Nov 23 '18 at 16:14
@HansPassant I use double because it doesn't have maximum range
– Burier Elia
Nov 23 '18 at 16:14
2
2
It trades range for precision. Double has only 53 bits to represent the value, the simplest RSA encryption key needs 330 bits. System.Security.Cryptograph has the code that can manipulate that many bits.
– Hans Passant
Nov 23 '18 at 16:23
It trades range for precision. Double has only 53 bits to represent the value, the simplest RSA encryption key needs 330 bits. System.Security.Cryptograph has the code that can manipulate that many bits.
– Hans Passant
Nov 23 '18 at 16:23
add a comment |
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2
The double type is not accurate enough to do this correctly, integer math is required. Use the System.Security.Cryptography namespace.
– Hans Passant
Nov 23 '18 at 15:05
thanks hans, but what's mean by integer math?, do you mean Integer data type? @HansPassant
– Burier Elia
Nov 23 '18 at 16:08
2
Consider googling "floating point math vs integer math" to find stuff to help you understand the difference.
– Hans Passant
Nov 23 '18 at 16:10
@HansPassant I use double because it doesn't have maximum range
– Burier Elia
Nov 23 '18 at 16:14
2
It trades range for precision. Double has only 53 bits to represent the value, the simplest RSA encryption key needs 330 bits. System.Security.Cryptograph has the code that can manipulate that many bits.
– Hans Passant
Nov 23 '18 at 16:23