(Classic ASP) 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

The in.dat file contains the original data that was signed, and can contain text or binary data of any type. The above OpenSSL command does the following:

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

Note: This example requires Chilkat v11.0.0 or greater.

Chilkat ActiveX Downloads

ActiveX for 32-bit and 64-bit Windows

<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
</head>
<body>
<%
success = 0

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

set pubKey = Server.CreateObject("Chilkat.PublicKey")

' Load the public key from an PEM file:
success = pubKey.LoadFromFile("pubKey.pem")
If (success = 0) Then
    Response.Write "<pre>" & Server.HTMLEncode( pubKey.LastErrorText) & "</pre>"
    Response.End
End If

' Load the data of the original file that was signed.
set bdFileData = Server.CreateObject("Chilkat.BinData")
success = bdFileData.LoadFile("in.dat")

' Load the signature.
set bdSig = Server.CreateObject("Chilkat.BinData")
success = bdSig.LoadFile("signature.sig")

set rsa = Server.CreateObject("Chilkat.Rsa")

' Import the public key into the RSA component:
success = rsa.UsePublicKey(pubKey)
If (success = 0) Then
    Response.Write "<pre>" & Server.HTMLEncode( rsa.LastErrorText) & "</pre>"
    Response.End
End If

' OpenSSL uses big-endian.
rsa.LittleEndian = 0

success = rsa.VerifyBd(bdFileData,"sha256",bdSig)
If (success <> 1) Then
    Response.Write "<pre>" & Server.HTMLEncode( rsa.LastErrorText) & "</pre>"
    Response.Write "<pre>" & Server.HTMLEncode( "The signature was invalid.") & "</pre>"
    Response.End
End If

Response.Write "<pre>" & Server.HTMLEncode( "The signature was verified.") & "</pre>"

%>
</body>
</html>