(Visual FoxPro) CAdES BES Attached (Opaque) Signature

Demonstrates how to create a CAdES BES attached signature file (.p7m). This is a PKCS7 signature format (known as an opaque, or "attached" signature) where the file data is embedded within the signature file. The signature verification both verifies the signature and extracts the original data.

(A "detached" signature is where the original data is NOT included within the PKCS7 signature format.)

Chilkat ActiveX Downloads ActiveX for 32-bit and 64-bit Windows

LOCAL loCrypt
LOCAL lcPfxPath
LOCAL lcPfxPassword
LOCAL loCert
LOCAL lnSuccess
LOCAL lcInFile
LOCAL lcSigFile
LOCAL lcExtractedToFilePath

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

* For versions of Chilkat < 10.0.0, use CreateObject('Chilkat_9_5_0.Crypt2')
loCrypt = CreateObject('Chilkat.Crypt2')

* Use a digital certificate and private key from a PFX file (.pfx or .p12).
lcPfxPath = "qa_data/pfx/myCertAndPrivateKey.p12"
lcPfxPassword = "password"

* For versions of Chilkat < 10.0.0, use CreateObject('Chilkat_9_5_0.Cert')
loCert = CreateObject('Chilkat.Cert')
lnSuccess = loCert.LoadPfxFile(lcPfxPath,lcPfxPassword)
IF (lnSuccess <> 1) THEN
    ? loCert.LastErrorText
    RELEASE loCrypt
    RELEASE loCert
    CANCEL
ENDIF

* Tell the crypt component to use this cert.
lnSuccess = loCrypt.SetSigningCert(loCert)
IF (lnSuccess <> 1) THEN
    ? loCrypt.LastErrorText
    RELEASE loCrypt
    RELEASE loCert
    CANCEL
ENDIF

* The CadesEnabled property applies to all methods that create PKCS7 signatures. 
* To create a CAdES-BES signature, set this property equal to true. 
loCrypt.CadesEnabled = 1

* To sign with SHA1, set the HashAlgorithm property to "sha1"
loCrypt.HashAlgorithm = "sha1"

* To sign with SHA256, set the HashAlgorithm property to "SHA256".
loCrypt.HashAlgorithm = "sha256"

* Other hash algorithm choices are "md5", "md2", "sha384", and "sha512"

* We can sign any type of file, creating a .p7m as output.
* The .p7m contains the signature and also embeds the data of the file that is signed.
lcInFile = "qa_data/json/sample.json"
lcSigFile = "qa_output/signature.p7m"

* -----------------------------------------------------------------------------------------
* Also see Chilkat's online tool to examine a .p7m and generate code to duplicate the .p7m
* -----------------------------------------------------------------------------------------

* Create the CAdES-BES attached signature, which contains the original data.
lnSuccess = loCrypt.CreateP7M(lcInFile,lcSigFile)
IF (lnSuccess = 0) THEN
    ? loCrypt.LastErrorText
    RELEASE loCrypt
    RELEASE loCert
    CANCEL
ENDIF

* Verify the .p7m file and extract the original file from the .p7m. 
lcExtractedToFilePath = "qa_output/sample.json"
lnSuccess = loCrypt.VerifyP7M(lcSigFile,lcExtractedToFilePath)
IF (lnSuccess = 0) THEN
    ? loCrypt.LastErrorText
    RELEASE loCrypt
    RELEASE loCert
    CANCEL
ENDIF

? "Success!"

RELEASE loCrypt
RELEASE loCert