VB.NET

Duplicate PHP RSA Encryption

See more RSA Examples

Demonstrates how to duplicate the following PHP function. VB.NET

Dim success As Boolean = False

' This example requires the Chilkat API to have been previously unlocked.
' See Global Unlock Sample for sample code.

' Duplicate the following PHP code:
' 
'    public function encryptRSA($plainText,$rsaMOD,$pubKEY){
'         $rsa  = new RSA();
'         $rsa->setEncryptionMode(RSA::ENCRYPTION_PKCS1);
'         $publicKey = [
'             'e' => new BigInteger($pubKEY,16),
'             'n' => new BigInteger($rsaMOD,16)
'         ];
' 		
'         $rsa->loadKey($publicKey);
'         $ciphertext = $rsa->encrypt($plainText);
'         return bin2hex($ciphertext);
'     }
' 
'     $plainText="key=abcdefghijkmnopq&iv=abcdefghijkmnopq&h=12345678&s=12345678"
'     $rsaMOD="F0946D8F05604809E24B8CFFD30349CEA9E5F4D320BFD9E9AA1B088863F02C43E7997D37A3E27B4F8F359F1744DB6B20A437067C0D325A80660D12FF56A57673"
'     $pubKEY="010001"

' We have the RSA modulus in hex
Dim rsaMOD As String = "F0946D8F05604809E24B8CFFD30349CEA9E5F4D320BFD9E9AA1B088863F02C43E7997D37A3E27B4F8F359F1744DB6B20A437067C0D325A80660D12FF56A57673"

' The RSA exponent in hex is "010001", which is 65537 in decimal.  It's typically the exponent that is always used.
Dim rsaEXP As String = "010001"

' Get the RSA modulus and exponent in base64.
Dim bdMod As New Chilkat.BinData
Dim bdExp As New Chilkat.BinData
success = bdMod.AppendEncoded(rsaMOD,"hex")
success = bdExp.AppendEncoded(rsaEXP,"hex")

' Build the XML representation of the RSA public key
Dim xml As New Chilkat.Xml
xml.Tag = "RSAPublicKey"
xml.UpdateChildContent("Modulus",bdMod.GetEncoded("base64"))
xml.UpdateChildContent("Exponent",bdExp.GetEncoded("base64"))

' Load the RSA public key into a Chilkat public key object.
Dim pubkey As New Chilkat.PublicKey
success = pubkey.LoadFromString(xml.GetXml())

' Setup the RSA object for encryption and do it..
Dim rsa As New Chilkat.Rsa
rsa.VerboseLogging = True
success = rsa.UsePublicKey(pubkey)

' Use PKCSv1.5 padding
rsa.PkcsPadding = True

' Encrypt and return the string as hex.
rsa.EncodingMode = "hex"
Dim plainText As String = "key=abcdefghijkmnopq&iv=abcdefghijkmnopq&h=12345678&s=12345678"
Dim cipherText As String = rsa.EncryptStringENC(plainText,False)
If (rsa.LastMethodSuccess = False) Then
    Debug.WriteLine(rsa.LastErrorText)
    Exit Sub
End If


' Note: The PKCSv1_5 padding incorporates random bytes.  Therefore, the RSA encryption will produce different results each time -- all of which are valid 
' and decrypt correctly to the same original text.
Debug.WriteLine(cipherText)