Create PKCS1 RSA Signature with PEM Private Key

Demonstrates how to load a private key from a PEM file and create a PKCS1 RSA digital signature.

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Dim pkey As New Chilkat.PrivateKey()

'  Load the private key from an RSA PEM file:
pkey.LoadPemFile("pvkey2_rsa.pem")

Dim success As Boolean

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

Dim rsa As New Chilkat.Rsa()

'  Any string argument automatically begins the 30-day trial.

success = rsa.UnlockComponent("30-day trial")
If (success <> true) Then
    MsgBox("RSA component unlock failed")
    Exit Sub
End If


'  Import the private key into the RSA component:
success = rsa.ImportPrivateKey(pkeyXml)
If (success <> true) Then
    MsgBox(rsa.LastErrorText)
    Exit Sub
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")

TextBox1.Text = TextBox1.Text & hexSig & vbCrLf
TextBox1.Refresh()

MsgBox("Success!")