(VBScript) RSA Encrypt RSA/ECB/OAEPWithSHA1AndMGF1Padding

Demonstrates how to RSA encrypt using RSA/ECB/OAEPWithSHA1AndMGF1Padding. Also demonstrates RSA/ECB/OAEPWithSHA-256AndMGF1Padding. Both of these terms are from Java's JCE. Note: In this context, "ECB" doesn't actually mean anything. It's a symmetric cipher mode that doesn't apply (or make sense) in this context.

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

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)

success = 0

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

set rsa = CreateObject("Chilkat.Rsa")

' First load a public key object with a public key.
' In this case, we'll load it from a file.
set pubkey = CreateObject("Chilkat.PublicKey")
success = pubkey.LoadFromFile("qa_data/pem/rsa_public.pem")
If (success = 0) Then
    outFile.WriteLine(pubkey.LastErrorText)
    WScript.Quit
End If

' RSA encryption is limited to small amounts of data. The limit
' is typically a few hundred bytes and is based on the key size and
' padding (OAEP vs. PKCS1_5).  RSA encryption is typically used for
' encrypting hashes or symmetric (bulk encryption algorithm) secret keys.
plainText = "Time is an illusion. Lunchtime doubly so."

' Import the public key to be used for encrypting.
success = rsa.UsePublicKey(pubkey)

' To get OAEP padding, set the PkcsPadding property equal to 0
rsa.PkcsPadding = 0
rsa.OaepHash = "sha256"

' Indicate we'll want hex output
rsa.EncodingMode = "hex"

' Encrypt..
usePrivateKey = 0
encryptedStr = rsa.EncryptStringENC(plainText,usePrivateKey)
outFile.WriteLine(encryptedStr)

' -------------------------------------------------
' Now decrypt with the matching private key.
set rsa2 = CreateObject("Chilkat.Rsa")

set privKey = CreateObject("Chilkat.PrivateKey")
success = privKey.LoadEncryptedPem("qa_data/pem/rsa_passwd.pem","passwd")
If (success = 0) Then
    outFile.WriteLine(privKey.LastErrorText)
    WScript.Quit
End If

success = rsa2.UsePrivateKey(privKey)

' Make sure we have the same settings used for encryption.
rsa2.PkcsPadding = 0
rsa2.EncodingMode = "hex"
rsa2.OaepHash = "sha256"

originalStr = rsa2.DecryptStringENC(encryptedStr,1)

outFile.WriteLine(originalStr)

outFile.Close