(Xojo Plugin) RSA Sign with PKCS8 Encrypted Key

Demonstrates how to load a private key from an encrypted PKCS8 file and create an RSA digital signature (and then verify it).

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 pkey As New Chilkat.PrivateKey

// Load the private key from an RSA PEM file:
Dim success As Boolean
success = pkey.LoadPkcs8EncryptedFile("raul_privateKey.key","a0123456789")

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

Dim rsa As New Chilkat.Rsa

// Import the private key into the RSA component:
success = rsa.ImportPrivateKey(pkeyXml)
If (success <> True) Then
    System.DebugLog(rsa.LastErrorText)
    Return
End If

// This example will sign a string, and receive the signature
// in a hex-encoded string.  Therefore, set the encoding mode
// to "hex":
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" and "md5".
Dim hexSig As String
hexSig = rsa.SignStringENC(strData,"sha-1")

System.DebugLog(hexSig)

// Now verify with the public key.
// This example shows how to use the public key from 
// a digital certificate (.cer file)
Dim cert As New Chilkat.Cert
success = cert.LoadFromFile("raul_publicKey.cer")
If (success <> True) Then
    System.DebugLog(cert.LastErrorText)
    Return
End If

Dim pubKey As Chilkat.PublicKey
pubKey = cert.ExportPublicKey()

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

Dim rsa2 As New Chilkat.Rsa
success = rsa2.ImportPublicKey(pubKeyXml)
If (success <> True) Then
    System.DebugLog(rsa2.LastErrorText)
    Return
End If

// Verify the signature against the original data:
rsa2.EncodingMode = "hex"
success = rsa2.VerifyStringENC(strData,"sha-1",hexSig)
If (success <> True) Then
    System.DebugLog(rsa2.LastErrorText)
    Return
End If

System.DebugLog("Signature verified!")

// Verify with incorrect data:
success = rsa2.VerifyStringENC("something else","sha-1",hexSig)
If (success <> True) Then
    System.DebugLog("Signature not verified! (which was expected in this case)")
Else
    System.DebugLog("Hmmm... that's not right...")
End If