Go

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.

Go

    success := false

    // 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.

    plaintext := "Live long and prosper."

    jwe := chilkat.NewJwe()

    // First build the JWE Protected Header..
    jweProtHdr := chilkat.NewJsonObject()
    jweProtHdr.AppendString("alg","dir")
    jweProtHdr.AppendString("enc","A128GCM")

    // Don't forget to actually provide the protected header to the JWE object:
    jwe.SetProtectedHeader(jweProtHdr)

    // 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.

    recipientIndex := 0
    jwe.SetWrappingKey(recipientIndex,"000102030405060708090A0B0C0D0E0F","hex")

    // Encrypt and return the JWE:
    strJwe := jwe.Encrypt(plaintext,"utf-8")
    if jwe.LastMethodSuccess() != true {
        fmt.Println(jwe.LastErrorText())
        jwe.DisposeJwe()
        jweProtHdr.DisposeJsonObject()
        return
    }

    // Show the JWE we just created:
    fmt.Println(*strJwe)

    // Decrypt the JWE.
    jwe2 := chilkat.NewJwe()
    success = jwe2.LoadJwe(*strJwe)
    if success != true {
        fmt.Println(jwe2.LastErrorText())
        jwe.DisposeJwe()
        jweProtHdr.DisposeJsonObject()
        jwe2.DisposeJwe()
        return
    }

    jwe2.SetWrappingKey(0,"000102030405060708090A0B0C0D0E0F","hex")

    // Decrypt.
    originalPlaintext := jwe2.Decrypt(0,"utf-8")
    if jwe2.LastMethodSuccess() != true {
        fmt.Println(jwe2.LastErrorText())
        jwe.DisposeJwe()
        jweProtHdr.DisposeJsonObject()
        jwe2.DisposeJwe()
        return
    }

    fmt.Println("original text: ")
    fmt.Println(*originalPlaintext)

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

    jwe.DisposeJwe()
    jweProtHdr.DisposeJsonObject()
    jwe2.DisposeJwe()