Xojo Plugin

RSA Signature/Verify with .key and .cer

See more RSA Examples

Demonstrates how to use a .key file (private key) and digital certificate (.cer, public key) to create and verify an RSA signature. Xojo Plugin

Dim success As Boolean
success = False

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

Dim privKey As New Chilkat.PrivateKey

// Load the private key from an RSA .key file:
success = privKey.LoadPemFile("privateKey.key")
If (success = False) Then
    System.DebugLog(privKey.LastErrorText)
    Return
End If

Dim rsa As New Chilkat.Rsa

// Import the private key into the RSA component:
success = rsa.UsePrivateKey(privKey)
If (success = False) Then
    System.DebugLog(rsa.LastErrorText)
    Return
End If

// Create the signature as a hex string:
rsa.EncodingMode = "hex"

Dim strData As String
strData = "This is the string to be signed."

// Sign the string using the sha256 hash algorithm.
// Other valid choices are "md2", "sha1", "sha384",
// "sha512", and "md5".
Dim hexSig As String
hexSig = rsa.SignStringENC(strData,"sha256")

System.DebugLog(hexSig)

// Load a digital certificate from a .cer file:
Dim cert As New Chilkat.Cert

success = cert.LoadFromFile("myCert.cer")
If (success = False) Then
    System.DebugLog(cert.LastErrorText)
    Return
End If

Dim pubKey As New Chilkat.PublicKey
success = cert.GetPublicKey(pubKey)

// Now verify using a new instance of the RSA object:
Dim rsa2 As New Chilkat.Rsa

// Import the public key into the RSA object:
success = rsa2.UsePublicKey(pubKey)
If (success = False) Then
    System.DebugLog(rsa2.LastErrorText)
    Return
End If

// The signature is a hex string, so make sure the EncodingMode is correct:
rsa2.EncodingMode = "hex"

// Verify the signature:
success = rsa2.VerifyStringENC(strData,"sha256",hexSig)
If (success = False) Then
    System.DebugLog(rsa2.LastErrorText)
    Return
End If

System.DebugLog("Success.")