Go

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.

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: {"alg":"A128KW","enc":"A128CBC-HS256"}
    jweProtHdr := chilkat.NewJsonObject()
    jweProtHdr.AppendString("alg","A128KW")
    jweProtHdr.AppendString("enc","A128CBC-HS256")
    jwe.SetProtectedHeader(jweProtHdr)

    fmt.Println("JWE Protected Header: ", *jweProtHdr.Emit())
    fmt.Println("--")

    // 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:
    aesWrappingKey := "GawgguFyGrWKav7AX4VKUg"
    jwe.SetWrappingKey(0,aesWrappingKey,"base64url")

    // 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 that was just produced.
    // 1) Load the JWE.
    // 2) Set the AES wrapping key.
    // 3) Decrypt.
    jwe2 := chilkat.NewJwe()
    success = jwe2.LoadJwe(*strJwe)
    if success != true {
        fmt.Println(jwe2.LastErrorText())
        jwe.DisposeJwe()
        jweProtHdr.DisposeJsonObject()
        jwe2.DisposeJwe()
        return
    }

    // Set the AES wrap key.
    jwe2.SetWrappingKey(0,aesWrappingKey,"base64url")

    // 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)

    // ---------------------------------------------------------------------------------
    // 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.

    sbJwe := chilkat.NewStringBuilder()
    sbJwe.Append("eyJhbGciOiJBMTI4S1ciLCJlbmMiOiJBMTI4Q0JDLUhTMjU2In0.")
    sbJwe.Append("6KB707dM9YTIgHtLvtgWQ8mKwboJW3of9locizkDTHzBC2IlrT1oOQ.")
    sbJwe.Append("AxY8DCtDaGlsbGljb3RoZQ.")
    sbJwe.Append("KDlTtXchhZTGufMYmOYGS4HffxPSUrfmqCHXaI9wOGY.")
    sbJwe.Append("U0m_YmjN04DJvceFICbCVQ")

    success = jwe2.LoadJweSb(sbJwe)
    if success != true {
        fmt.Println(jwe2.LastErrorText())
        jwe.DisposeJwe()
        jweProtHdr.DisposeJsonObject()
        jwe2.DisposeJwe()
        sbJwe.DisposeStringBuilder()
        return
    }

    jwe2.SetWrappingKey(0,aesWrappingKey,"base64url")

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

    fmt.Println(*originalPlaintext)

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