(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.

Chilkat Xojo Plugin Download

Xojo Plugin for Windows, Linux, Mac OS X, and ARM, ARM64

// 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:
Dim success As Boolean
success = privKey.LoadPemFile("privateKey.key")
If (success <> True) Then
    System.DebugLog(privKey.LastErrorText)
    Return
End If

Dim privKeyXml As String
// Get the private key in XML format:
privKeyXml = privKey.GetXml()

Dim rsa As New Chilkat.Rsa

// Import the private key into the RSA component:
success = rsa.ImportPrivateKey(privKeyXml)
If (success <> True) 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 sha-1 hash algorithm.
// Other valid choices are "md2", "sha256", "sha384",
// "sha512", and "md5".
Dim hexSig As String
hexSig = rsa.SignStringENC(strData,"sha-1")

System.DebugLog(hexSig)

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

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

Dim pubKey As Chilkat.PublicKey

pubKey = cert.ExportPublicKey()

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

// Import the public key into the RSA object:
success = rsa2.ImportPublicKey(pubKey.GetXml())
If (success <> True) 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,"sha-1",hexSig)
If (success <> True) Then
    System.DebugLog(rsa2.LastErrorText)
    Return
End If

System.DebugLog("Success.")