B4X

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. B4X

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 ChilkatCert
cert.Initialize("cert")

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


Dim crypt As ChilkatCrypt2
crypt.Initialize("crypt")

success = crypt.SetSigningCert(cert)
If success <> True Then
    Log(crypt.LastErrorText)
    Return
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
    Log(crypt.LastErrorText)
    Return
End If


Log(sigBase64)

'  The result:

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

'  If we want it in PEM format with just LF line-endings:
Dim sb As ChilkatStringBuilder
sb.Initialize
'  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..
Log(sb.GetAsString)

'  Result is:

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