Visual FoxPro
Create PEM-encoded PKCS#7 Detached Signature

Demonstrates how to create a PKCS7 PEM-encoded object containing a detached signature.
Chilkat Visual FoxPro Downloads

Visual FoxPro
LOCAL lnSuccess
LOCAL loCert
LOCAL loCrypt
LOCAL lcTextToSign
LOCAL lcSigBase64
LOCAL loSb
LOCAL lnCrlf

lnSuccess = 0

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

loCert = CreateObject('Chilkat.Cert')

*  Load the cert and private key.
lnSuccess = loCert.LoadPfxFile("qa_data/pfx/myCertAndKey.p12","password")
IF (lnSuccess <> 1) THEN
    ? loCert.LastErrorText
    RELEASE loCert
    CANCEL
ENDIF

loCrypt = CreateObject('Chilkat.Crypt2')

lnSuccess = loCrypt.SetSigningCert(loCert)
IF (lnSuccess <> 1) THEN
    ? loCrypt.LastErrorText
    RELEASE loCert
    RELEASE loCrypt
    CANCEL
ENDIF

*  Use SHA-256
loCrypt.HashAlgorithm = "sha256"

*  Hash the utf-8 byte representation of the string
loCrypt.Charset = "utf-8"

*  Return the result in base64
loCrypt.EncodingMode = "base64Mime"

*  Sign some text to create a detached signature (i.e. a signature that does not include the signed data)
lcTextToSign = "This is the text to be hashed and signed."
lcSigBase64 = loCrypt.SignStringENC(lcTextToSign)
IF (loCrypt.LastMethodSuccess <> 1) THEN
    ? loCrypt.LastErrorText
    RELEASE loCert
    RELEASE loCrypt
    CANCEL
ENDIF

? lcSigBase64

*  The result:

*  MIIWbgYJKoZIhvcNAQcCoIIWXzCCFlsCAQExDzANBglghkgBZQMEAgEFADALBgkqhkiG9w0BBwGg
*  ghMXMIIFuzCCA6OgAwIBAgIIVwoRl0LE48wwDQYJKoZIhvcNAQELBQAwazELMAkGA1UEBhMCSVQx
*  ...
*  ...

*  If we want it in PEM format with just LF line-endings:
loSb = CreateObject('Chilkat.StringBuilder')
*  Just LF line endings, not CRLF.
lnCrlf = 0
loSb.AppendLine("-----BEGIN PKCS7-----",lnCrlf)
loSb.Append(lcSigBase64)
loSb.AppendLine("-----END PKCS7-----",lnCrlf)
loSb.ToLF()

*  Save to a file.
loSb.WriteFile("c:/temp/qa_output/sig.pem","utf-8",0)

*  Examine..
? loSb.GetAsString()

*  Result is:

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

RELEASE loCert
RELEASE loCrypt
RELEASE loSb