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

See more JSON Web Signatures (JWS) Examples

Creates and validates a JSON Web Signature (JWS) using the private key associated with a certificate on a smart card.

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

Use ChilkatAx-win32.pkg

Procedure Test
    Handle hoCert
    Boolean iSuccess
    Variant vPrivKey
    Handle hoPrivKey
ProtHdr    Handle hoJwsProtHdr
    Handle hoJws
    Integer iSignatureIndex
    Boolean iBIncludeBom
    String sPayloadStr
    String sJwsCompact
    Handle hoJws2
    Variant vRsaPubKey
    Handle hoRsaPubKey
    Integer v
    Variant vJoseHeader
    Handle hoJoseHeader
    String sTemp1
    Boolean bTemp1

    // 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
    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).

    // If the associated private key was present on the smartcard, then you can simply
    // get it from the Chilkat cert object:
    Get ComExportPrivateKey Of hoCert To vPrivKey
    If (IsComObject(vPrivKey)) Begin
        Get Create (RefClass(cComChilkatPrivateKey)) To hoPrivKey
        Set pvComObject Of hoPrivKey To vPrivKey
    End
    Get ComLastMethodSuccess Of hoCert To bTemp1
    If (bTemp1 = False) Begin
        Get ComLastErrorText Of hoCert To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    // You can check the key type to make sure it's RSA.
    // This will output "rsa" if the key is RSA.
    Get ComKeyType Of hoPrivKey To sTemp1
    Showln "Key type = " sTemp1

    // Create the JWS Protected Header
    Get Create (RefClass(cComChilkatJsonObject)) To hoJwsProtHdr
    If (Not(IsComObjectCreated(hoJwsProtHdr))) Begin
        Send CreateComObject of hoJwsProtHdr
    End
    Get ComAppendString Of hoJwsProtHdr "alg" "RS256" To iSuccess

    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

    // Set the RSA key:
    Get ComSetPrivateKey Of hoJws iSignatureIndex vPrivKey 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 <> True) Begin
        Get ComLastErrorText Of hoJws To sTemp1
        Showln sTemp1
        Send Destroy of hoPrivKey
        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 ComGetPublicKey Of hoPrivKey To vRsaPubKey
    If (IsComObject(vRsaPubKey)) Begin
        Get Create (RefClass(cComChilkatPublicKey)) To hoRsaPubKey
        Set pvComObject Of hoRsaPubKey To vRsaPubKey
    End
    Send Destroy of hoPrivKey

    // Set the RSA public key used for validation.
    Move 0 To iSignatureIndex
    Get ComSetPublicKey Of hoJws2 iSignatureIndex vRsaPubKey To iSuccess
    Send Destroy of hoRsaPubKey

    // 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 RSA 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 ComGetProtectedHeader Of hoJws2 iSignatureIndex To vJoseHeader
    If (IsComObject(vJoseHeader)) Begin
        Get Create (RefClass(cComChilkatJsonObject)) To hoJoseHeader
        Set pvComObject Of hoJoseHeader To vJoseHeader
    End
    Get ComLastMethodSuccess Of hoJws2 To bTemp1
    If (bTemp1 <> True) Begin
        Showln "No protected header found at the given index."
        Procedure_Return
    End

    Set ComEmitCompact Of hoJoseHeader To False

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

    // Output:

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


End_Procedure