Classic ASP
RSA Encrypt Bytes to Base64 and Reverse

Demonstrates how to RSA encrypt bytes to base64 and the reverse.
Chilkat Classic ASP Downloads

Classic ASP
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success = 0

' 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.
set pubKey = Server.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
    Response.Write "<pre>" & Server.HTMLEncode( pubKey.LastErrorText) & "</pre>"
    Response.End
End If

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

' Tell RSA to use the public key.
success = rsa.UsePublicKey(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

' A typical use for RSA is to encrypt symmetric encryption keys, such as an AES key.
set prng = Server.CreateObject("Chilkat.Prng")

keyBytes = prng.GenRandomBytes(32)

rsa.EncodingMode = "base64"
encryptedB64 = rsa.EncryptBytesENC(keyBytes,0)

Response.Write "<pre>" & Server.HTMLEncode( "Result:") & "</pre>"
Response.Write "<pre>" & Server.HTMLEncode( encryptedB64) & "</pre>"

' Sample output:
' hTTV4Lbmm2V7NCw/HaoJL8Aq/MM/HXblQnjitrF9HY1zBlISwui2jGVVZDtZcZ/rICOpPw44w8Qb8AswFVE1sryydmNEvcIfYAp/xgdBPXBERAS0y4AoEzUfuC5TJmJFvnFkl2lX8GAclANfcTik38V+k3EXu5wPzHKNFb07c6jnwh3Jm4f3PRUhmmB2NO5kSWqHsx0dNglOTq5BUZx34nxlXL5G8d7mXqITsUtrOHXAO/Gb7IrvB81Xk2vc5p4yHhiY/rFTHTTmZyzte2qHGm7V6xPRNURjiivnMY2jQU0Um1JKQcAiSe8Suwvd2LXP5PIhl71VLgO+fokjnynfRg==

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

' Load the matching 2048-bit RSA private key.
set privKey = Server.CreateObject("Chilkat.PrivateKey")
password = "secret"
success = privKey.LoadAnyFormatFile("qa_data/rsaKeys/myTestRsaPrivate.pem",password)
If (success = 0) Then
    Response.Write "<pre>" & Server.HTMLEncode( privKey.LastErrorText) & "</pre>"
    Response.End
End If

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

decBytes = rsa.DecryptBytesENC(encryptedB64,1)
If (success = 0) Then
    Response.Write "<pre>" & Server.HTMLEncode( rsa.LastErrorText) & "</pre>"
    Response.End
End If

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

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