Sign a File to Create a .p7s File (Detached Signature)

Visual FoxPro example to create a detached signature file (.p7s) for any type file. The signature can be verified by calling VerifyP7S and passing the original filename and the .p7s filename.

Download Chilkat Crypt ActiveX

LOCAL loCrypt
LOCAL lnSuccess
LOCAL loCcs
LOCAL loCertStore
LOCAL loCert

loCrypt = CreateObject('Chilkat.Crypt2')

*  Any string argument automatically begins the 30-day trial.

lnSuccess = loCrypt.UnlockComponent("30-day trial")
IF (lnSuccess <> 1) THEN
    =MESSAGEBOX("Crypt component unlock failed")
    QUIT
ENDIF

*  Find our digital certificate from the Current User certificate store.
loCcs = CreateObject('Chilkat.CreateCS')

loCertStore = loCcs.OpenCurrentUserStore()

loCert = loCertStore.FindCertBySubjectCN("Chilkat Software, Inc.")
IF (loCert = NULL ) THEN
    =MESSAGEBOX(loCert.LastErrorText)
    RELEASE loCertStore
    QUIT
ENDIF

*  Tell the crypt component to use this cert.
loCrypt.SetSigningCert(loCert)

RELEASE loCertStore

*  We can sign any type of file, creating a .p7s as output:
lnSuccess = loCrypt.CreateP7S("license.rtf","license.p7s")
IF (lnSuccess = 0) THEN
    =MESSAGEBOX(loCrypt.LastErrorText)
    RELEASE loCert
    QUIT
ENDIF

*  Verify the signature:
loCrypt.SetVerifyCert(loCert)

lnSuccess = loCrypt.VerifyP7S("license.rtf","license.p7s")
IF (lnSuccess = 0) THEN
    =MESSAGEBOX(loCrypt.LastErrorText)
    RELEASE loCert
    QUIT
ENDIF

RELEASE loCert

=MESSAGEBOX("Success!")