Classic ASP Requires Chilkat v11.0.0+
RSA Encrypt and Decrypt Strings

_LANGUAGE_ sample code to RSA public-key encrypt and decrypt strings using public and private keys.
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Classic ASP
<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")

'  This example also generates the public and private
'  keys to be used in the RSA encryption.
'  Normally, you would generate a key pair once,
'  and distribute the public key to your partner.
'  Anything encrypted with the public key can be
'  decrypted with the private key.  The reverse is 
'  also true: anything encrypted using the private
'  key can be decrypted using the public key.

'  Generate a 2048-bit key.  Chilkat RSA supports
'  key sizes ranging from 512 bits to 4096 bits.
set privKey = Server.CreateObject("Chilkat.PrivateKey")
success = rsa.GenKey(2048,privKey)
If (success = 0) Then
    Response.Write "<pre>" & Server.HTMLEncode( rsa.LastErrorText) & "</pre>"
    Response.End
End If

set pubKey = Server.CreateObject("Chilkat.PublicKey")
success = privKey.ToPublicKey(pubKey)

plainText = "Encrypting and decrypting should be easy!"

'  Start with a new RSA object to demonstrate that all we
'  need are the keys previously exported:
set rsaEncryptor = Server.CreateObject("Chilkat.Rsa")

'  Encrypted output is always binary.  In this case, we want
'  to encode the encrypted bytes in a printable string.
'  Our choices are "hex", "base64", "url", "quoted-printable".
rsaEncryptor.EncodingMode = "hex"

'  We'll encrypt with the public key and decrypt with the private
'  key.
success = rsaEncryptor.UsePublicKey(pubKey)

usePrivateKey = 0
encryptedStr = rsaEncryptor.EncryptStringENC(plainText,usePrivateKey)
Response.Write "<pre>" & Server.HTMLEncode( encryptedStr) & "</pre>"

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

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

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

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

%>
</body>
</html>