(VB.NET) Convert RSA Private Key to Public Key

Demonstrates how to get a public RSA key from a private RSA key.

Chilkat .NET Downloads Chilkat .NET Framework Chilkat for .NET Core

Dim key As New Chilkat.PrivateKey

' Step 1: Load the private key from a source.
' (Chilkat can load private keys from all types of formats, and from in-memory bytes or encoded strings.
' see the online reference documentation for more options.)
Dim success As Boolean = key.LoadPemFile("qa_data/pem/VP_Private.pem")
If (success <> True) Then
    Debug.WriteLine(key.LastErrorText)
    Exit Sub
End If


' Step 2: Get the public key object from the private key object.
Dim pubKey As Chilkat.PublicKey = key.GetPublicKey()
If (key.LastMethodSuccess <> True) Then
    Debug.WriteLine(key.LastErrorText)
    Exit Sub
End If


' Step 3: Save the public key in a desired format. 
' (Chilkat can load or save public and private keys in many different formats.  See
' the online reference documentation for more options.)

' Saves to a PKCS8 PEM file.
Dim bPreferPkcs1 As Boolean = False
success = pubKey.SavePemFile(bPreferPkcs1,"qa_data/pem/VP_Public.pem")
If (pubKey.LastMethodSuccess <> True) Then
    Debug.WriteLine(pubKey.LastErrorText)
    Exit Sub
End If




Debug.WriteLine("Extracted and saved public key from private key.")