DataFlex

JWE using A256GCMKW

See more JSON Web Encryption (JWE) Examples

This example demonstrates creating a JCE with AES GCM key wrap. DataFlex

Use ChilkatAx-win32.pkg

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

    Move "My text to enrypt" 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": "A256GCMKW",
    //             "kid": "18ec08e1-bfa9-4d95-b205-2b4dd1d4321d",
    //             "tag": "kfPduVQ3T3H6vnewt--ksw",
    //             "iv": "KkYT0GX_2jHlfqN_",
    //             "enc": "A128CBC-HS256"
    //         }

    Get Create (RefClass(cComChilkatJsonObject)) To hoJweProtHdr
    If (Not(IsComObjectCreated(hoJweProtHdr))) Begin
        Send CreateComObject of hoJweProtHdr
    End
    Get ComAppendString Of hoJweProtHdr "alg" "A256GCMKW" To iSuccess
    // kid is optional
    Get ComAppendString Of hoJweProtHdr "kid" "18ec08e1-bfa9-4d95-b205-2b4dd1d4321d" To iSuccess
    // tag is optional
    Get ComAppendString Of hoJweProtHdr "tag" "kfPduVQ3T3H6vnewt--ksw" To iSuccess
    Get ComAppendString Of hoJweProtHdr "enc" "A256GCM" To iSuccess
    // the iv should be 16 random chars.
    Get Create (RefClass(cComChilkatPrng)) To hoPrng
    If (Not(IsComObjectCreated(hoPrng))) Begin
        Send CreateComObject of hoPrng
    End
    Get ComRandomString Of hoPrng 16 True True True To sTemp1
    Get ComAppendString Of hoJweProtHdr "iv" sTemp1 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 "--"

    // Given that we have 256-bit AES, our key should be 32 bytes.
    // The ascii string here is 32 bytes, therefore the 2nd arg is "ascii" to use these
    // ascii chars directly as the key.
    Move "2baf4f730f5e4542b428593ef9cceb0e" To sAesWrappingKey
    Get ComSetWrappingKey Of hoJwe 0 sAesWrappingKey "ascii" 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.  Important to use "ascii"
    Get ComSetWrappingKey Of hoJwe2 0 sAesWrappingKey "ascii" 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


End_Procedure