(DataFlex) Create JWS Using Private Key on a Smart Card

See more JSON Web Signatures (JWS) Examples

Note: This example requires Chilkat v11.5.0 or greater.

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

Use ChilkatAx-win32.pkg

Procedure Test
    Boolean iSuccess
    Variant vCert
    Handle hoCert
ProtHdr    Handle hoJwsProtHdr
    Handle hoJws
    Integer iSignatureIndex
    Boolean iBIncludeBom
    String sPayloadStr
    String sJwsCompact
2    Handle hoJws2
    Variant vPubKey
    Handle hoPubKey
    Integer v
    Variant vJoseHeader
    Handle hoJoseHeader
    String sTemp1
    Boolean bTemp1

    Move False To iSuccess

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

    // Load the certificate from a smart card.
    Get Create (RefClass(cComChilkatCert)) To hoCert
    If (Not(IsComObjectCreated(hoCert))) Begin
        Send CreateComObject of hoCert
    End

    // Set the smarcard PIN prior to loading.
    Set ComSmartCardPin Of hoCert To "123456"

    // Detect the connected smartcard or USB security token and load the default certificate.
    Get ComLoadFromSmartcard Of hoCert "" To iSuccess
    If (iSuccess = False) Begin
        Get ComLastErrorText Of hoCert To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    // Note: Chilkat provides many different ways to load a certificate from a smartcard or USB token,
    // such as selecting a certificate if the card contains multiple certificates with private keys,
    // or working with lower-level PKCS11 or ScMinidriver API's (both of which Chilkat provides).

    // Create the JWS Protected Header
    Get Create (RefClass(cComChilkatJsonObject)) To hoJwsProtHdr
    If (Not(IsComObjectCreated(hoJwsProtHdr))) Begin
        Send CreateComObject of hoJwsProtHdr
    End

    Get ComIsEcdsa Of hoCert To bTemp1
    If (bTemp1 = True) Begin
        Get ComAppendString Of hoJwsProtHdr "alg" "ES256" To iSuccess
    End
    Else Begin
        Get ComAppendString Of hoJwsProtHdr "alg" "RS256" To iSuccess
    End

    Get Create (RefClass(cComChilkatJws)) To hoJws
    If (Not(IsComObjectCreated(hoJws))) Begin
        Send CreateComObject of hoJws
    End

    // Set the protected header:
    Move 0 To iSignatureIndex
    Get pvComObject of hoJwsProtHdr to vJwsProtHdr
    Get ComSetProtectedHeader Of hoJws iSignatureIndex vJwsProtHdr To iSuccess

    // Provide the private key via the certificate.
    // This requires Chilkat v11.5.0 or greater.
    Get pvComObject of hoCert to vCert
    Get ComSetSigningCert Of hoJws iSignatureIndex vCert To iSuccess

    // Set the payload.
    Move False To iBIncludeBom
    Move "In our village, folks say God crumbles up the old moon into stars." To sPayloadStr
    Get ComSetPayload Of hoJws sPayloadStr "utf-8" iBIncludeBom To iSuccess

    // Create the JWS
    // By default, the compact serialization is used.
    Get ComCreateJws Of hoJws To sJwsCompact
    Get ComLastMethodSuccess Of hoJws To bTemp1
    If (bTemp1 = False) Begin
        Get ComLastErrorText Of hoJws To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    Showln "JWS: " sJwsCompact

    // sample output:
    // JWS: eyJhbGciOiJQUzI1NiJ9.SW4gb3VyIHZpbGxhZ2UsIGZvbGtzIHNheSBHb2QgY3J1bWJsZXMgdXAgdGhlIG9sZCBtb29uIGludG8gc3RhcnMu.TRWhwRo5dMv9-8OzrInfJTwmUGYgjLfHk8lqF072ND-FmLWEBnUTOpY8oJXp8FdWw2SalbdOeNlrtlJjwk4XK8Ql2iJ_2qMCtxsvLPhKBOqFoAF4aBvTOEDVJDxf0DaBSiydEEtfTVV2iwBcjWabu5J2XieR5y7QZQtuHsn7T3qKBvCcCejN3Y2oqAT3qMHvu1fTms1r_91wBn_K7Wjd9UkZ1n02qQcUHJznR_OF2BgN7_KWIDAF9ZS9keoju2NPpPelO4yxa2XUPnehY3G7dHKoCxUEQR4d2Xc5voqDASTVCDqQS4PVOZdvT3Ein6-SanAlCwbWBbkvT8g6-5PImQ

    // Now load the JWS, validate, and recover the original text.
    Get Create (RefClass(cComChilkatJws)) To hoJws2
    If (Not(IsComObjectCreated(hoJws2))) Begin
        Send CreateComObject of hoJws2
    End

    // Load the JWS.
    Get ComLoadJws Of hoJws2 sJwsCompact To iSuccess

    Get Create (RefClass(cComChilkatPublicKey)) To hoPubKey
    If (Not(IsComObjectCreated(hoPubKey))) Begin
        Send CreateComObject of hoPubKey
    End
    Get pvComObject of hoPubKey to vPubKey
    Get ComGetPublicKey Of hoCert vPubKey To iSuccess

    // Set the public key used for validation.
    Move 0 To iSignatureIndex
    Get pvComObject of hoPubKey to vPubKey
    Get ComSetPublicKey Of hoJws2 iSignatureIndex vPubKey To iSuccess

    // Validate the 1st (and only) signature at index 0..
    Get ComValidate Of hoJws2 iSignatureIndex To v
    If (v < 0) Begin
        // Perhaps Chilkat was not unlocked or the trial expired..
        Showln "Method call failed for some other reason."
        Get ComLastErrorText Of hoJws2 To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    If (v = 0) Begin
        Showln "Invalid signature.  The key was incorrect, the JWS was invalid, or both."
        Procedure_Return
    End

    // If we get here, the signature was validated..
    Showln "Signature validated."

    // Recover the original content:
    Get ComGetPayload Of hoJws2 "utf-8" To sTemp1
    Showln sTemp1

    // Examine the protected header:

    Get Create (RefClass(cComChilkatJsonObject)) To hoJoseHeader
    If (Not(IsComObjectCreated(hoJoseHeader))) Begin
        Send CreateComObject of hoJoseHeader
    End
    Get pvComObject of hoJoseHeader to vJoseHeader
    Get ComGetProtectedH Of hoJws2 iSignatureIndex vJoseHeader To iSuccess
    If (iSuccess = False) Begin
        Get ComLastErrorText Of hoJws2 To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    Set ComEmitCompact Of hoJoseHeader To False

    Showln "Protected (JOSE) header:"
    Get ComEmit Of hoJoseHeader To sTemp1
    Showln sTemp1

    // Output:

    // 	Signature validated.
    // 	In our village, folks say God crumbles up the old moon into stars.
    // 	Protected (JOSE) header:
    // 	{ 
    // 	  "alg": "RS256"
    // 	}


End_Procedure