DataFlex

JWE using AES Key Wrap and AES_128_CBC_HMAC_SHA_256

See more JSON Web Encryption (JWE) Examples

This example duplicates the example A.3 in RFC 7516 for JSON Web Encryption (JWE).

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

DataFlex

Use ChilkatAx-win32.pkg

Procedure Test
    Boolean iSuccess
    String sPlaintext
    Handle hoJwe
    Variant vJweProtHdr
    Handle hoJweProtHdr
    String sAesWrappingKey
    String sStrJwe
    Handle hoJwe2
    String sOriginalPlaintext
    Variant vSbJwe
    Handle hoSbJwe
    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.

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

    Move "Live long and prosper." To sPlaintext

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

    // First build the JWE Protected Header: {"alg":"A128KW","enc":"A128CBC-HS256"}
    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

    Get ComEmit Of hoJweProtHdr To sTemp1
    Showln "JWE Protected Header: " sTemp1
    Showln "--"

    // The example A.3 in RFC 7516 uses the following 128-bit AES key,
    // specified in JWK (JSON Web Key) format:
    //      {"kty":"oct",
    //       "k":"GawgguFyGrWKav7AX4VKUg"
    //      }
    // This is just a way of saying: The key type ("kty") is 
    // a bunch of octets ("k") in base64url encoding.
    // We can simply set the AES wrapping key like this:
    Move "GawgguFyGrWKav7AX4VKUg" To sAesWrappingKey
    Get ComSetWrappingKey Of hoJwe 0 sAesWrappingKey "base64url" To iSuccess

    // Encrypt and return the JWE:
    Get ComEncrypt Of hoJwe sPlaintext "utf-8" To sStrJwe
    Get ComLastMethodSuccess Of hoJwe To bTemp1
    If (bTemp1 <> True) Begin
        Get ComLastErrorText Of hoJwe To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    // Show the JWE we just created:
    Showln sStrJwe

    // Decrypt the JWE that was just produced.
    // 1) Load the JWE.
    // 2) Set the AES wrapping key.
    // 3) Decrypt.
    Get Create (RefClass(cComChilkatJwe)) To hoJwe2
    If (Not(IsComObjectCreated(hoJwe2))) Begin
        Send CreateComObject of hoJwe2
    End
    Get ComLoadJwe Of hoJwe2 sStrJwe 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 ComDecrypt Of hoJwe2 0 "utf-8" To sOriginalPlaintext
    Get ComLastMethodSuccess Of hoJwe2 To bTemp1
    If (bTemp1 <> True) Begin
        Get ComLastErrorText Of hoJwe2 To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    Showln "original text: "
    Showln sOriginalPlaintext

    // ---------------------------------------------------------------------------------
    // It should also be possible to decrypt the JWE as shown in RFC 7516, Appendix A.3.7
    // because it was produced using the same AES Wrap key.

    Get Create (RefClass(cComChilkatStringBuilder)) To hoSbJwe
    If (Not(IsComObjectCreated(hoSbJwe))) Begin
        Send CreateComObject of hoSbJwe
    End
    Get ComAppend Of hoSbJwe "eyJhbGciOiJBMTI4S1ciLCJlbmMiOiJBMTI4Q0JDLUhTMjU2In0." To iSuccess
    Get ComAppend Of hoSbJwe "6KB707dM9YTIgHtLvtgWQ8mKwboJW3of9locizkDTHzBC2IlrT1oOQ." To iSuccess
    Get ComAppend Of hoSbJwe "AxY8DCtDaGlsbGljb3RoZQ." To iSuccess
    Get ComAppend Of hoSbJwe "KDlTtXchhZTGufMYmOYGS4HffxPSUrfmqCHXaI9wOGY." To iSuccess
    Get ComAppend Of hoSbJwe "U0m_YmjN04DJvceFICbCVQ" To iSuccess

    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

    Get ComSetWrappingKey Of hoJwe2 0 sAesWrappingKey "base64url" To iSuccess

    // Decrypt.
    Get ComDecrypt Of hoJwe2 0 "utf-8" To sOriginalPlaintext
    Get ComLastMethodSuccess Of hoJwe2 To bTemp1
    If (bTemp1 <> True) Begin
        Get ComLastErrorText Of hoJwe2 To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    Showln sOriginalPlaintext


End_Procedure