(PureBasic) RSA Signature with Certificate's Private Key from PFX

See more RSA Examples

Demonstrates how to use a certificate's private key from a PFX file to create an RSA signature.

Chilkat PureBasic Module Download Chilkat PureBasic Module

IncludeFile "CkCertStore.pb"
IncludeFile "CkCert.pb"
IncludeFile "CkPrivateKey.pb"
IncludeFile "CkRsa.pb"

Procedure ChilkatExample()

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

    ; Create an instance of a certificate store object, load a PFX file,
    ; locate the certificate we need, and use it for signing.
    ; (a PFX file may contain more than one certificate.)
    certStore.i = CkCertStore::ckCreate()
    If certStore.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    ; The 1st argument is the filename, the 2nd arg is the 
    ; PFX file's password:
    success.i = CkCertStore::ckLoadPfxFile(certStore,"chilkat.pfx","test")
    If success <> 1
        Debug CkCertStore::ckLastErrorText(certStore)
        CkCertStore::ckDispose(certStore)
        ProcedureReturn
    EndIf

    cert.i = CkCertStore::ckFindCertBySubject(certStore,"Chilkat Software, Inc.")
    If CkCertStore::ckLastMethodSuccess(certStore) = 0
        Debug CkCertStore::ckLastErrorText(certStore)
        CkCertStore::ckDispose(certStore)
        ProcedureReturn
    EndIf

    pkey.i = CkCert::ckExportPrivateKey(cert)
    If CkCert::ckLastMethodSuccess(cert) = 0
        Debug CkCert::ckLastErrorText(cert)
        CkCert::ckDispose(cert)

        CkCertStore::ckDispose(certStore)
        ProcedureReturn
    EndIf

    CkCert::ckDispose(cert)

    ; Get the private key in XML format:
    pkeyXml.s = CkPrivateKey::ckGetXml(pkey)

    rsa.i = CkRsa::ckCreate()
    If rsa.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    ; Import the private key into the RSA component:
    success = CkRsa::ckImportPrivateKey(rsa,pkeyXml)
    If success <> 1
        Debug CkRsa::ckLastErrorText(rsa)
        CkPrivateKey::ckDispose(pkey)

        CkCertStore::ckDispose(certStore)
        CkRsa::ckDispose(rsa)
        ProcedureReturn
    EndIf

    ; Encode the signature as a hex string
    CkRsa::setCkEncodingMode(rsa, "hex")

    strData.s = "This is the string to be signed."

    ; Sign the string using the sha-1 hash algorithm.
    ; Other valid choices are "sha-256", "md2" and "md5".
    hexSig.s = CkRsa::ckSignStringENC(rsa,strData,"sha-1")

    Debug hexSig

    CkPrivateKey::ckDispose(pkey)

    Debug "Success!"


    CkCertStore::ckDispose(certStore)
    CkRsa::ckDispose(rsa)


    ProcedureReturn
EndProcedure