(DataFlex) JWS Using HMAC SHA-256

Creates a JSON Web Signatures (JWS) using HMAC SHA-256.

Note: This example requires Chilkat v9.5.0.66 or greater.

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

Use ChilkatAx-win32.pkg

Procedure Test
    Boolean iSuccess
ProtHdr    Handle hoJwsProtHdr
    Handle hoJws
    String sHmacKey
    Integer iSignatureIndex
    Boolean iBIncludeBom
    String sPayloadStr
    String sJwsCompact
    Handle hoJws2
    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.

    // Note: This example requires Chilkat v9.5.0.66 or greater.

    // First 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 "typ" "JWT" To iSuccess
    Get ComAppendString Of hoJwsProtHdr "alg" "HS256" To iSuccess
    Get ComEmit Of hoJwsProtHdr To sTemp1
    Showln "JWS Protected Header: " sTemp1

    // Output:
    // JWS Protected Header: {"typ":"JWT","alg":"HS256"}

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

    // Set the HMAC key:
    Move "AyM1SysPpbyDfgZld3umj1qzKObwVMkoqQ-EstJQLr_T-1qS0gZH75aKtMN3Yj0iPS4hcgUuTwjAzZr1Z9CAow" To sHmacKey
    Move 0 To iSignatureIndex
    Get ComSetMacKey Of hoJws iSignatureIndex sHmacKey "base64url" To iSuccess

    // Set the protected header:
    Get pvComObject of hoJwsProtHdr to vJwsProtHdr
    Get ComSetProtectedHeader Of hoJws iSignatureIndex vJwsProtHdr 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
        Procedure_Return
    End

    Showln "JWS: " sJwsCompact

    // sample output:
    // JWS: eyJ0eXAiOiJKV1QiLCJhbGciOiJIUzI1NiJ9.SW4gb3VyIHZpbGxhZ2UsIGZvbGtzIHNheSBHb2QgY3J1bWJsZXMgdXAgdGhlIG9sZCBtb29uIGludG8gc3RhcnMu.bsYsi8HJ0N6OqGI1hKQ9QQRNPxxA5qMpcHLtOvXatk8

    // 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

    // Set the MAC key used for validation.
    Move 0 To iSignatureIndex
    Get ComSetMacKey Of hoJws2 iSignatureIndex sHmacKey "base64url" 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 MAC 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:
    // 	{ 
    // 	  "typ": "JWT",
    // 	  "alg": "HS256"
    // 	} 


End_Procedure