DataFlex

JWE with Binary Data

See more JSON Web Encryption (JWE) Examples

Demonstrates how to create a JWE that contains a binary payload (such as a JPG image).

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

DataFlex

Use ChilkatAx-win32.pkg

Procedure Test
    Boolean iSuccess
    Variant vJpgBytes
    Handle hoJpgBytes
    Handle hoJwe
ProtHdr    Handle hoJweProtHdr
    String sAesWrappingKey
    Variant vSbJwe
    Handle hoSbJwe
2    Handle hoJwe2
    Variant vJpgOriginal
    Handle hoJpgOriginal
    String sTemp1
    Integer iTemp1

    Move False To iSuccess

    // 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.

    // Load a JPG file that will be the JWE payload.
    Get Create (RefClass(cComChilkatBinData)) To hoJpgBytes
    If (Not(IsComObjectCreated(hoJpgBytes))) Begin
        Send CreateComObject of hoJpgBytes
    End
    Get ComLoadFile Of hoJpgBytes "qa_data/jpg/starfish.jpg" To iSuccess
    // Make sure your app checks the success/failure of the call to LoadFile..
    Get ComNumBytes Of hoJpgBytes To iTemp1
    Showln "Original JPG size = " iTemp1

    Get Create (RefClass(cComChilkatJwe)) To hoJwe
    If (Not(IsComObjectCreated(hoJwe))) Begin
        Send CreateComObject of hoJwe
    End

    Get Create (RefClass(cComChilkatJsonObject)) To hoJweProtHdr
    If (Not(IsComObjectCreated(hoJweProtHdr))) Begin
        Send CreateComObject of hoJweProtHdr
    End
    Get ComAppendString Of hoJweProtHdr "alg" "A128KW" To iSuccess
    Get ComAppendString Of hoJweProtHdr "enc" "A128CBC-HS256" To iSuccess
    Get pvComObject of hoJweProtHdr to vJweProtHdr
    Get ComSetProtectedHeader Of hoJwe vJweProtHdr To iSuccess

    Move "GawgguFyGrWKav7AX4VKUg" To sAesWrappingKey
    Get ComSetWrappingKey Of hoJwe 0 sAesWrappingKey "base64url" To iSuccess

    // Encrypt and return the JWE in sbJwe:
    Get Create (RefClass(cComChilkatStringBuilder)) To hoSbJwe
    If (Not(IsComObjectCreated(hoSbJwe))) Begin
        Send CreateComObject of hoSbJwe
    End
    Get pvComObject of hoJpgBytes to vJpgBytes
    Get pvComObject of hoSbJwe to vSbJwe
    Get ComEncryptBd Of hoJwe vJpgBytes vSbJwe To iSuccess
    If (iSuccess <> True) Begin
        Get ComLastErrorText Of hoJwe To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    // Show the JWE:
    Get ComGetAsString Of hoSbJwe To sTemp1
    Showln sTemp1
    Get ComLength Of hoSbJwe To iTemp1
    Showln "size of JWE: " iTemp1

    // ---------------------------------------------------------
    // Decrypt to get the original JPG file..

    Get Create (RefClass(cComChilkatJwe)) To hoJwe2
    If (Not(IsComObjectCreated(hoJwe2))) Begin
        Send CreateComObject of hoJwe2
    End
    Get pvComObject of hoSbJwe to vSbJwe
    Get ComLoadJweSb Of hoJwe2 vSbJwe To iSuccess
    If (iSuccess <> True) Begin
        Get ComLastErrorText Of hoJwe2 To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    // Set the AES wrap key.
    Get ComSetWrappingKey Of hoJwe2 0 sAesWrappingKey "base64url" To iSuccess

    // Decrypt.
    Get Create (RefClass(cComChilkatBinData)) To hoJpgOriginal
    If (Not(IsComObjectCreated(hoJpgOriginal))) Begin
        Send CreateComObject of hoJpgOriginal
    End
    Get pvComObject of hoJpgOriginal to vJpgOriginal
    Get ComDecryptBd Of hoJwe2 0 vJpgOriginal To iSuccess
    If (iSuccess <> True) Begin
        Get ComLastErrorText Of hoJwe2 To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    Get ComNumBytes Of hoJpgOriginal To iTemp1
    Showln "Decrypted JPG size = " iTemp1

    // Save the decrypted JPG to a file.
    Get ComWriteFile Of hoJpgOriginal "qa_output/jwe_decrypted_starfish.jpg" To iSuccess

    Showln "success = " iSuccess

    // The output of this program, when tested, was:
    // Original JPG size = 6229
    // eyJhbGciOiJBMTI4S1ciLCJlbmMiOiJBMTI4Q0JDLUhTMjU2In0.9YFz_wteV ... 7Et3hKhpxnKEXw
    // size of JWE: 8473
    // Decrypted JPG size = 6229
    // success = True


End_Procedure