VB.NET

Create PEM-encoded PKCS#7 Detached Signature

See more Digital Signatures Examples

Demonstrates how to create a PKCS7 PEM-encoded object containing a detached signature. VB.NET

Dim success As Boolean = False

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

Dim cert As New Chilkat.Cert

' Load the cert and private key.
success = cert.LoadPfxFile("qa_data/pfx/myCertAndKey.p12","password")
If (success <> True) Then
    Debug.WriteLine(cert.LastErrorText)
    Exit Sub
End If


Dim crypt As New Chilkat.Crypt2

success = crypt.SetSigningCert(cert)
If (success <> True) Then
    Debug.WriteLine(crypt.LastErrorText)
    Exit Sub
End If


' Use SHA-256
crypt.HashAlgorithm = "sha256"

' Hash the utf-8 byte representation of the string
crypt.Charset = "utf-8"

' Return the result in base64
crypt.EncodingMode = "base64Mime"

' Sign some text to create a detached signature (i.e. a signature that does not include the signed data)
Dim textToSign As String = "This is the text to be hashed and signed."
Dim sigBase64 As String = crypt.SignStringENC(textToSign)
If (crypt.LastMethodSuccess <> True) Then
    Debug.WriteLine(crypt.LastErrorText)
    Exit Sub
End If


Debug.WriteLine(sigBase64)

' The result:

' MIIWbgYJKoZIhvcNAQcCoIIWXzCCFlsCAQExDzANBglghkgBZQMEAgEFADALBgkqhkiG9w0BBwGg
' ghMXMIIFuzCCA6OgAwIBAgIIVwoRl0LE48wwDQYJKoZIhvcNAQELBQAwazELMAkGA1UEBhMCSVQx
' ...
' ...

' If we want it in PEM format with just LF line-endings:
Dim sb As New Chilkat.StringBuilder
' Just LF line endings, not CRLF.
Dim crlf As Boolean = False
sb.AppendLine("-----BEGIN PKCS7-----",crlf)
sb.Append(sigBase64)
sb.AppendLine("-----END PKCS7-----",crlf)
sb.ToLF()

' Save to a file.
sb.WriteFile("c:/temp/qa_output/sig.pem","utf-8",False)

' Examine..
Debug.WriteLine(sb.GetAsString())

' Result is:

' -----BEGIN PKCS7-----
' MIIWbgYJKoZIhvcNAQcCoIIWXzCCFlsCAQExDzANBglghkgBZQMEAgEFADALBgkqhkiG9w0BBwGg
' ghMXMIIFuzCCA6OgAwIBAgIIVwoRl0LE48wwDQYJKoZIhvcNAQELBQAwazELMAkGA1UEBhMCSVQx
' DjAMBgNVBAcMBU1pbGFuMSMwIQYDVQQKDBpBY3RhbGlzIFMucC5BLi8wMzM1ODUyMDk2NzEnMCUG
' A1UEAwweQWN0YWxpcyBBdXRoZW50aWNhdGlvbiBSb290IENBMB4XDTExMDkyMjExMjIwMloXDTMw
' MDkyMjExMjIwMlowazELMAkGA1UEBhMCSVQxDjAMBgNVBAcMBU1pbGFuMSMwIQYDVQQKDBpBY3Rh
' bGlzIFMucC5BLi8wMzM1ODUyMDk2NzEnMCUGA1UEAwweQWN0YWxpcyBBdXRoZW50aWNhdGlvbiBS
' b290IENBMIICIjANBgkqhkiG9w0BAQEFAAOCAg8AMIICCgKCAgEAp8bEpSmkLO/lGMWwUKNvUTuf
' ClrJwkg4CsIcoBh/kbWHuUA/3R1oHwiD1S0eiKD4j1aPbZkCkpAW1V8IbInX4ay8IMKx4INRimlN
' AJZaby/ARH6jDuSRzVju3PvHHkVH3Se5CAGfpiEd9UEtL0z9KK3giq0itFZljoZUj5NDKd45Rnij
' MCO6zfB9E1fAXdKDa0hMxKufgFpbOr3JpyI/gCczWw63igxdBzcIy2zSekciRDXFzMwujt0q7bd9
' ...
' ...
' -----END PKCS7-----