(AutoIt) RSA-OAEP with SHA256 hashing

RSA encrypt a SHA256 hash with OAEP padding.

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

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

$oPubkey = ObjCreate("Chilkat.PublicKey")

$oSbPem = ObjCreate("Chilkat.StringBuilder")
Local $bCrlf = True
$oSbPem.AppendLine("-----BEGIN PUBLIC KEY-----",$bCrlf)
$oSbPem.AppendLine("MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEA33TqqLR3eeUmDtHS89qF",$bCrlf)
$oSbPem.AppendLine("3p4MP7Wfqt2Zjj3lZjLjjCGDvwr9cJNlNDiuKboODgUiT4ZdPWbOiMAfDcDzlOxA",$bCrlf)
$oSbPem.AppendLine("04DDnEFGAf+kDQiNSe2ZtqC7bnIc8+KSG/qOGQIVaay4Ucr6ovDkykO5Hxn7OU7s",$bCrlf)
$oSbPem.AppendLine("Jp9TP9H0JH8zMQA6YzijYH9LsupTerrY3U6zyihVEDXXOv08vBHk50BMFJbE9iwF",$bCrlf)
$oSbPem.AppendLine("wnxCsU5+UZUZYw87Uu0n4LPFS9BT8tUIvAfnRXIEWCha3KbFWmdZQZlyrFw0buUE",$bCrlf)
$oSbPem.AppendLine("f0YN3/Q0auBkdbDR/ES2PbgKTJdkjc/rEeM0TxvOUf7HuUNOhrtAVEN1D5uuxE1W",$bCrlf)
$oSbPem.AppendLine("SwIDAQAB",$bCrlf)
$oSbPem.AppendLine("-----END PUBLIC KEY-----",$bCrlf)

; Load the public key object from the PEM. 
Local $bSuccess = $oPubkey.LoadFromString($oSbPem.GetAsString())
If ($bSuccess <> True) Then
    ConsoleWrite($oPubkey.LastErrorText & @CRLF)
    Exit
EndIf

; Build a small string to encrypt
$oJson = ObjCreate("Chilkat.JsonObject")
$oJson.UpdateString("example","123")
$oJson.UpdateString("hello","world")
ConsoleWrite($oJson.Emit() & @CRLF)

; This is the JSON to be RSA encrypted:  {"example":"123","hello":"world"}

; IMPORTANT: RSA encryption is only used to encrypt small amounts of data.
; RSA is only able to encrypt data to a maximum amount of your key size (2048 bits = 256 bytes) 
; minus padding / header data (11 bytes for PKCS#1 v1.5 padding, 42 bytes for OAEP).
; As a result it is often not possible to encrypt files with RSA directly. 
; RSA is also not meant for this purpose. 
; 
; If you want to encrypt more data, you can use something like:
; 1) Generate a 256-bit random keystring K
; 2) Encrypt your data with AES-CBC with K
; 3) Encrypt K with RSA
; 4) Send both to the other side 

$oRsa = ObjCreate("Chilkat.Rsa")
$oRsa.OaepPadding = True
$oRsa.OaepHash = "SHA-256"
$oRsa.ImportPublicKeyObj($oPubkey)
$oRsa.EncodingMode = "base64"

; Note: The OAEP padding uses random bytes in the padding, and therefore each time encryption happens,
; even using the same data and key, the result will be different --  but still valid.  One should not expect
; to get the same output.
Local $bUsePrivateKey = False
Local $sEncryptedStr = $oRsa.EncryptStringENC($oJson.Emit(),$bUsePrivateKey)
If ($oRsa.LastMethodSuccess <> True) Then
    ConsoleWrite($oRsa.LastErrorText & @CRLF)
    Exit
EndIf

ConsoleWrite("Result: " & $sEncryptedStr & @CRLF)