(DataFlex) Create a JWS Using ECDSA P-256 SHA-256

Creates and validates a JSON Web Signature (JWS) that uses ECDSA P-256 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
    Handle hoSbJwk
    Boolean iSuccess
    Variant vEccKey
    Handle hoEccKey
    Boolean iSuccess
ProtHdr    Handle hoJwsProtHdr
    Handle hoJws
    Integer iSignatureIndex
    Boolean iBIncludeBom
    String sPayloadStr
    String sJwsCompact
    Handle hoJws2
    Variant vEccPubKey
    Handle hoEccPubKey
    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.

    // Use the following ECC key loaded from JWK format.
    Get Create (RefClass(cComChilkatStringBuilder)) To hoSbJwk
    If (Not(IsComObjectCreated(hoSbJwk))) Begin
        Send CreateComObject of hoSbJwk
    End
    Get ComAppend Of hoSbJwk '{"kty":"EC",' To iSuccess
    Get ComAppend Of hoSbJwk '"crv":"P-256",' To iSuccess
    Get ComAppend Of hoSbJwk '"x":"f83OJ3D2xF1Bg8vub9tLe1gHMzV76e8Tus9uPHvRVEU",' To iSuccess
    Get ComAppend Of hoSbJwk '"y":"x_FEzRu9m36HLN_tue659LNpXW6pCyStikYjKIWI5a0",' To iSuccess
    Get ComAppend Of hoSbJwk '"d":"jpsQnnGQmL-YBIffH1136cspYG6-0iY7X1fCE9-E9LI"' To iSuccess
    Get ComAppend Of hoSbJwk "}" To iSuccess

    Get Create (RefClass(cComChilkatPrivateKey)) To hoEccKey
    If (Not(IsComObjectCreated(hoEccKey))) Begin
        Send CreateComObject of hoEccKey
    End
    // Note: This example loads the ECDSA key from JWK format.  Any format can be loaded
    // into the private key object. (See the online reference documentation..)
    Get ComGetAsString Of hoSbJwk To sTemp1
    Get ComLoadJwk Of hoEccKey sTemp1 To iSuccess
    If (iSuccess <> True) Begin
        Get ComLastErrorText Of hoEccKey To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    // 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" "ES256" 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 ECC key:
    Get pvComObject of hoEccKey to vEccKey
    Get ComSetPrivateKey Of hoJws iSignatureIndex vEccKey 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

    // Note: ECC signatures use random values, so the output will be different each time a signature is produced.
    // sample output:
    // JWS: eyJhbGciOiJFUzI1NiJ9.SW4gb3VyIHZpbGxhZ2UsIGZvbGtzIHNheSBHb2QgY3J1bWJsZXMgdXAgdGhlIG9sZCBtb29uIGludG8gc3RhcnMu.J6EGTNkeuEjehHHBu0SOKzifm8r35wbx49A5964pxzB7gannyZZPMkK7vmlaPJ-K8Xmm8cZsQySAPC12Xd8avw

    // 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 hoEccKey To vEccPubKey
    If (IsComObject(vEccPubKey)) Begin
        Get Create (RefClass(cComChilkatPublicKey)) To hoEccPubKey
        Set pvComObject Of hoEccPubKey To vEccPubKey
    End

    // Set the ECC public key used for validation.
    Move 0 To iSignatureIndex
    Get ComSetPublicKey Of hoJws2 iSignatureIndex vEccPubKey To iSuccess
    Send Destroy of hoEccPubKey

    // 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 ECC 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": "ES256"
    // }


End_Procedure