RSA Sign with PKCS8 Encrypted Key

Demonstrates how to load a private key from an encrypted PKCS8 file and create an RSA digital signature.

Download Chilkat RSA ActiveX

Dim pkey As New PrivateKey

'  Load the private key from an RSA PEM file:
pkey.LoadPkcs8EncryptedFile "privateKey.key","myPassword"

Dim success As Long

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

Dim rsa As New ChilkatRsa

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

success = rsa.UnlockComponent("30-day trial")
If (success <> 1) Then
    MsgBox "RSA component unlock failed"
    Exit Sub
End If

'  Import the private key into the RSA component:
success = rsa.ImportPrivateKey(pkeyXml)
If (success <> 1) 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")

Text1.Text = Text1.Text & hexSig & vbCrLf