(VB.NET) Duplicate openssl dgst -sha256 -verify pubKey.pem -signature signature.sig in.dat

Demonstrates how to duplicate this OpenSSL command:

openssl dgst -sha256 -verify pubKey.pem -signature signature.sig in.dat

1. Creates a SHA256 digest of the contents of the input file.
2. Verifies the SHA256 digest using the public key.

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

' This example requires the Chilkat API to have been previously unlocked.
' See Global Unlock Sample for sample code.

Dim pubKey As New Chilkat.PublicKey

' Load the public key from an PEM file:
Dim success As Boolean = pubKey.LoadFromFile("pubKey.pem")
If (success <> True) Then
    Debug.WriteLine(pubKey.LastErrorText)
    Exit Sub
End If



' Load the data of the original file that was signed.
Dim bdFileData As New Chilkat.BinData
success = bdFileData.LoadFile("in.dat")

' Load the signature.
Dim bdSig As New Chilkat.BinData
success = bdSig.LoadFile("signature.sig")


Dim rsa As New Chilkat.Rsa

' Import the public key into the RSA component:
success = rsa.ImportPublicKeyObj(pubKey)
If (success <> True) Then
    Debug.WriteLine(rsa.LastErrorText)
    Exit Sub
End If


' OpenSSL uses big-endian.
rsa.LittleEndian = False

success = rsa.VerifyBd(bdFileData,"sha256",bdSig)
If (success <> True) Then
    Debug.WriteLine(rsa.LastErrorText)
    Debug.WriteLine("The signature was invalid.")
    Exit Sub
End If


Debug.WriteLine("The signature was verified.")