(VBScript) RSA Encrypt String to Binary Result and Reverse

See more RSA Examples

Demonstrates how to RSA encrypt a string to a binary result, and the reverse.

Chilkat ActiveX Downloads ActiveX for 32-bit and 64-bit Windows

Dim fso, outFile
Set fso = CreateObject("Scripting.FileSystemObject")
'Create a Unicode (utf-16) output text file.
Set outFile = fso.CreateTextFile("output.txt", True, True)

' The RSA public key is used for encryption, and the private key for decryption.

' The public key's role is to make encryption accessible to anyone while ensuring that
' only the private key holder can decrypt the messages.
' The public key is designed to be widely distributed so anyone can use it to encrypt messages
' intended for the owner of the private key.

' Load our 2048-bit RSA public key.
' For versions of Chilkat < 10.0.0, use CreateObject("Chilkat_9_5_0.PublicKey")
set pubKey = CreateObject("Chilkat.PublicKey")
' In all Chilkat methods expecting a path, you pass either absolute or relative paths.
success = pubKey.LoadFromFile("qa_data/rsaKeys/myTestRsaPublic.pem")
If (success = 0) Then
    outFile.WriteLine(pubKey.LastErrorText)
    WScript.Quit
End If

' For versions of Chilkat < 10.0.0, use CreateObject("Chilkat_9_5_0.Rsa")
set rsa = CreateObject("Chilkat.Rsa")

' Tell RSA to use the public key.
success = rsa.ImportPublicKeyObj(pubKey)

' RSA encryption is for small amounts of data, on the order of 200 bytes or less.
' The maximum number of bytes that can be RSA encrypted depends
' on the RSA key size and padding scheme (OAEP padding vs PKCS#1 v1.5 padding).
' For specific limits, see: RSA Encryption Maximum Number of Bytes

' Encrypt the utf-8 byte representation of the string.
rsa.Charset = "utf-8"

' Be Careful when Using non-us-ascii String Literals in Source Code

encBytes = rsa.EncryptString("Élève français dîne à côté d’un café où l’on sert déjà du gâteau au chocolat et des éclairs délicieux",0)

' ------------------------------------------------------------------------------------------------------------------------
' Let's decrypt, which requires the matching private key...

' Load the matching 2048-bit RSA private key.
' For versions of Chilkat < 10.0.0, use CreateObject("Chilkat_9_5_0.PrivateKey")
set privKey = CreateObject("Chilkat.PrivateKey")
password = "secret"
success = privKey.LoadAnyFormatFile("qa_data/rsaKeys/myTestRsaPrivate.pem",password)
If (success = 0) Then
    outFile.WriteLine(privKey.LastErrorText)
    WScript.Quit
End If

' Tell the RSA object to use the private key.
success = rsa.ImportPrivateKeyObj(privKey)

' Indicate that after decrypting the resultant decrypted bytes contains the utf-8 byte representation of the text.
rsa.Charset = "utf-8"
originalText = rsa.DecryptString(encBytes,1)
If (success = 0) Then
    outFile.WriteLine(rsa.LastErrorText)
    WScript.Quit
End If

outFile.WriteLine("Original text = " & originalText)
outFile.WriteLine("Success.")

outFile.Close