DataFlex

JWE using "dir" Direct use of Shared Symmetric Key

See more JSON Web Encryption (JWE) Examples

Demonstrates how to create a JWE using the "dir" alg -- which is to directly use a shared symmetric key.

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
    Integer iRecipientIndex
    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.

    // 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..
    Get Create (RefClass(cComChilkatJsonObject)) To hoJweProtHdr
    If (Not(IsComObjectCreated(hoJweProtHdr))) Begin
        Send CreateComObject of hoJweProtHdr
    End
    Get ComAppendString Of hoJweProtHdr "alg" "dir" To iSuccess
    Get ComAppendString Of hoJweProtHdr "enc" "A128GCM" To iSuccess

    // Don't forget to actually provide the protected header to the JWE object:
    Get pvComObject of hoJweProtHdr to vJweProtHdr
    Get ComSetProtectedHeader Of hoJwe vJweProtHdr To iSuccess

    // The JWE is to use 128-bit AES GCM encryption as specified by the "enc" parameter.
    // Given that the "alg" = "dir", we are to directly specify the AES GCM key.
    // (It is assumed that the decrypting side also has knowledge of the direct key to be used..)

    // Our key will be these 16 hex bytes: 000102030405060708090A0B0C0D0E0F

    // The SetWrappingKey method is also used for "dir" direct keys.
    // However, if there are multiple recipients, they must all share the same CEK (Content Encryption Key),
    // which is specified by calling SetWrappingKey with an index of 0.

    Move 0 To iRecipientIndex
    Get ComSetWrappingKey Of hoJwe iRecipientIndex "000102030405060708090A0B0C0D0E0F" "hex" 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.
    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

    Get ComSetWrappingKey Of hoJwe2 0 "000102030405060708090A0B0C0D0E0F" "hex" 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

    // Sample output:
    // eyJhbGciOiJkaXIiLCJlbmMiOiJBMTI4R0NNIn0..20HX5Huc7f1nQC4pBUtiCQ.axFZIxtZy5j0ifJQUzGXLKIpsBuxJA.eBrOC-NrsreN6JeGuOPk1g
    // original text: 
    // Live long and prosper.


End_Procedure