B4X

Trust Specific Root CA Certificates

See more Certificates Examples

Demonstrates how to trust specific root CA certificates and none others. B4X

Dim success As Boolean = False

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

'  This example will trust the Amazon root CA certificates provided at 
'  https://www.amazontrust.com/repository/

'  I've previously downloaded the root CA certificates to DER format.
'  Add each to the Chilkat TrustedRoots singleton object.

Dim tRoots As ChilkatTrustedRoots
tRoots.Initialize("tRoots")

Dim caCert As ChilkatCert
caCert.Initialize("caCert")
success = caCert.LoadFromFile("qa_data/certs/aws_root_ca/AmazonRootCA1.cer")
If success = False Then
    Log(caCert.LastErrorText)
    Return
End If

success = tRoots.AddCert(caCert)

'  Continue with the others.
'  For brevity, we're not checking return values for success/failure.
success = caCert.LoadFromFile("qa_data/certs/aws_root_ca/AmazonRootCA2.cer")
success = tRoots.AddCert(caCert)

success = caCert.LoadFromFile("qa_data/certs/aws_root_ca/AmazonRootCA3.cer")
success = tRoots.AddCert(caCert)

success = caCert.LoadFromFile("qa_data/certs/aws_root_ca/AmazonRootCA4.cer")
success = tRoots.AddCert(caCert)

success = caCert.LoadFromFile("qa_data/certs/aws_root_ca/SFSRootCAG2.cer")
success = tRoots.AddCert(caCert)

'  Indicate we don't want to automatically trust the operating system's installed root CA certificates.
'  On a Windows operating system, this would be the registry-based CA certificate stores. 
'  On a Linux system, this could be /etc/ssl/certs/ca-certificates.crt, if it exists.
tRoots.TrustSystemCaRoots = False

'  Activate the trusted roots object.
'  Once activated, all Chilkat objects that use TLS connections (HTTP, REST, Socket, MailMan, IMAP, FTP, etc.)
'  will fail the TLS handshake if the server certificate is not verified and rooted with one of our explicitly trusted root certificates.
success = tRoots.Activate

Dim http As ChilkatHttp
http.Initialize("http")

'  Note: We also need to explicitly indicate that server certificates are to be verified.
http.RequireSslCertVerify = True

'  For example, the following should fail because www.chilkatsoft.com's server certificate is not rooted in one of the explicitly trusted root CA certs.
success = http.Download("https://www.chilkatsoft.com/helloWorld.txt", "qa_output/helloWorld.txt")
If success <> True Then
    '  The above Download should fail.
    Log(http.LastErrorText)

    '  There should be a message in the LastErrorText indicating that we were "Unable to build certificate chain to root.."
End If


'  However, we should be able to make TLS connections to good.sca1a.amazontrust.com
success = http.Download("https://good.sca1a.amazontrust.com/", "qa_output/valid.html")
If success <> True Then
    Log(http.LastErrorText)
    Return
End If


'  We can still examine the LastErrorText and we'll find this message within:  
'  "The public key was successfully validated against the public key of the explicitly trusted root cert."
Log(http.LastErrorText)

Log("Success!")