(Classic ASP) RSA Encrypt and Decrypt Credit Card Numbers

Classic ASP sample code to RSA public-key encrypt and decrypt credit card numbers. The RSA key is loaded from an unencrypted PKCS8 file. Chilkat provides many ways of setting the key -- loading from both encrypted and unencrypted PEM, PKCS8, DER, PVK, etc. Keys may be loaded from files or in-memory representations. (The RSA component also provides the ability to generate RSA keys.)

Note: This example requires Chilkat v11.0.0 or greater.

Chilkat ActiveX Downloads

ActiveX for 32-bit and 64-bit Windows

<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
</head>
<body>
<%
success = 0

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

set rsa = Server.CreateObject("Chilkat.Rsa")

set privKey = Server.CreateObject("Chilkat.PrivateKey")

' Load an RSA private key from a file:
success = privKey.LoadAnyFormatFile("rsaPrivateKey.key","")
If (success = 0) Then
    Response.Write "<pre>" & Server.HTMLEncode( privKey.LastErrorText) & "</pre>"
    Response.End
End If

' Get the public part of the private key.
set pubKey = Server.CreateObject("Chilkat.PublicKey")
success = privKey.ToPublicKey(pubKey)

success = rsa.UsePublicKey(pubKey)
If (success = 0) Then
    Response.Write "<pre>" & Server.HTMLEncode( rsa.LastErrorText) & "</pre>"
    Response.End
End If

' Encrypt a VISA credit card number:
' 1234-5678-0000-9999
ccNumber = "1234567800009999"

usePrivateKey = 0
rsa.EncodingMode = "base64"
encryptedStr = rsa.EncryptStringENC(ccNumber,usePrivateKey)
Response.Write "<pre>" & Server.HTMLEncode( "Encrypted:") & "</pre>"
Response.Write "<pre>" & Server.HTMLEncode( encryptedStr) & "</pre>"

' Now decrypt:
set rsaDecryptor = Server.CreateObject("Chilkat.Rsa")

rsaDecryptor.EncodingMode = "base64"
success = rsaDecryptor.UsePrivateKey(privKey)

usePrivateKey = 1
decryptedStr = rsaDecryptor.DecryptStringENC(encryptedStr,usePrivateKey)

Response.Write "<pre>" & Server.HTMLEncode( "Decrypted:") & "</pre>"
Response.Write "<pre>" & Server.HTMLEncode( decryptedStr) & "</pre>"

' Important: RSA encryption should only be used to encrypt small amounts of data.
' It is typically used for encrypting symmetric encryption
' keys such that a symmetric encryption algorithm, such as 
' AES is then used to encrypt/decrypt bulk data

%>
</body>
</html>