(Go) JWE with DEFLATE Compression

Demonstrates how to DEFLATE ("zip") compress the JWE payload prior to encryption.

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

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    // 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.

    var success bool
    // Create some plaintext to be encrypted.
    // This example will demonstrate with and without DEFLATE (zip) compression.
    sbPlainText := chilkat.NewStringBuilder()
    bCrLf := true
    line := "Live long and prosper."
    sbPlainText.AppendLine(line,bCrLf)
    sbPlainText.AppendLine(line,bCrLf)
    sbPlainText.AppendLine(line,bCrLf)
    sbPlainText.AppendLine(line,bCrLf)

    // The text to be encrypted:
    fmt.Println(*sbPlainText.GetAsString())

    jwe := chilkat.NewJwe()

    // Build the JWE Protected Header: {"alg":"A128KW","enc":"A128CBC-HS256","zip":"DEF"}
    // The "zip":"DEF" parameter indicates that the plaintext payload should
    // be compressed prior to encryption.
    jweProtHdr := chilkat.NewJsonObject()
    jweProtHdr.AppendString("alg","A128KW")
    jweProtHdr.AppendString("enc","A128CBC-HS256")
    jweProtHdr.AppendString("zip","DEF")
    jwe.SetProtectedHeader(jweProtHdr)

    // Set the AES key wrap key:
    aesWrappingKey := "GawgguFyGrWKav7AX4VKUg"
    jwe.SetWrappingKey(0,aesWrappingKey,"base64url")

    // Encrypt and return the JWE in sbJweCompressed:
    sbJweCompressed := chilkat.NewStringBuilder()
    success = jwe.EncryptSb(sbPlainText,"utf-8",sbJweCompressed)
    if success != true {
        fmt.Println(jwe.LastErrorText())
        sbPlainText.DisposeStringBuilder()
        jwe.DisposeJwe()
        jweProtHdr.DisposeJsonObject()
        sbJweCompressed.DisposeStringBuilder()
        return
    }

    // Show the compressed JWE:
    fmt.Println(*sbJweCompressed.GetAsString())
    fmt.Println("size of compressed JWE: ", sbJweCompressed.Length())

    // Now create a JWE without compression.
    jweProtHdr.Delete("zip")
    // Make sure to update the shared protected header:
    jwe.SetProtectedHeader(jweProtHdr)

    sbJweUncompressed := chilkat.NewStringBuilder()
    success = jwe.EncryptSb(sbPlainText,"utf-8",sbJweUncompressed)
    if success != true {
        fmt.Println(jwe.LastErrorText())
        sbPlainText.DisposeStringBuilder()
        jwe.DisposeJwe()
        jweProtHdr.DisposeJsonObject()
        sbJweCompressed.DisposeStringBuilder()
        sbJweUncompressed.DisposeStringBuilder()
        return
    }

    // Show the uncompressed JWE:
    fmt.Println(*sbJweUncompressed.GetAsString())
    fmt.Println("size of uncompressed JWE: ", sbJweUncompressed.Length())

    // Decrypting is the same whether compression is used or not.
    // The "zip" header in the JWE indicates that the payload should be 
    // automatically decompressed (inflated) after decrypting.
    jwe2 := chilkat.NewJwe()
    success = jwe2.LoadJweSb(sbJweCompressed)
    if success != true {
        fmt.Println(jwe2.LastErrorText())
        sbPlainText.DisposeStringBuilder()
        jwe.DisposeJwe()
        jweProtHdr.DisposeJsonObject()
        sbJweCompressed.DisposeStringBuilder()
        sbJweUncompressed.DisposeStringBuilder()
        jwe2.DisposeJwe()
        return
    }

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

    // Decrypt (also automatically decompresses).
    sbOriginalText := chilkat.NewStringBuilder()
    success = jwe2.DecryptSb(0,"utf-8",sbOriginalText)
    if success != true {
        fmt.Println(jwe2.LastErrorText())
        sbPlainText.DisposeStringBuilder()
        jwe.DisposeJwe()
        jweProtHdr.DisposeJsonObject()
        sbJweCompressed.DisposeStringBuilder()
        sbJweUncompressed.DisposeStringBuilder()
        jwe2.DisposeJwe()
        sbOriginalText.DisposeStringBuilder()
        return
    }

    fmt.Println("original text from compressed JWE: ")
    fmt.Println(*sbOriginalText.GetAsString())

    // -----------------------------------------------------------
    // Do the same with the uncompressed JWE

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

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

    // Decrypt.
    sbOriginalText.Clear()
    success = jwe2.DecryptSb(0,"utf-8",sbOriginalText)
    if success != true {
        fmt.Println(jwe2.LastErrorText())
        sbPlainText.DisposeStringBuilder()
        jwe.DisposeJwe()
        jweProtHdr.DisposeJsonObject()
        sbJweCompressed.DisposeStringBuilder()
        sbJweUncompressed.DisposeStringBuilder()
        jwe2.DisposeJwe()
        sbOriginalText.DisposeStringBuilder()
        return
    }

    fmt.Println("original text from uncompressed JWE: ")
    fmt.Println(*sbOriginalText.GetAsString())

    // ------------------------------------------------
    // The output of this example is:
    // (Note: Your output data will be different because the content encryption key is randomly generated.)

    // eyJhbGciOiJBMTI4S1ciLCJlbmMiOiJBMTI4Q0JDLUhTMjU2IiwiemlwIjoiREVGIn0.xuW-pEAIdEUFnk10m8ocursvktO8Of9ByCCAt6LgKkkOtCWCUn1kQw.zpGj-9WVni3cQxyOuZbcGA.0hzP1myua3oYpUHwCIY_3edBUREbUpLaX6wYuJduOdI.Ppc6aEO3y3B8BJ1FKMPjlA
    // size of compressed JWE: 212
    // eyJhbGciOiJBMTI4S1ciLCJlbmMiOiJBMTI4Q0JDLUhTMjU2In0.N4KeyC7nnSFkieJOyE24_zKeuV_m7v5UKoJb1TgV4Yc_r2RzUPNvyA.6AEdyXSCKx-iMmUJyypSLg.QpixfyrwhGpmwUDp623viik4smPav7vwPLiC2r-V-jwnSfEH3mxWu6DbrIz3mixaqATwynmEBzVPxvS9jTXpSAGCnniib4_0WoPl3r_wF5tlsKOEe--jpNso-DKd1Tp8jJxj3JkFWt3IRnUUKGj17g.sBfDwFc5fzpaI-UW8-SW4g
    // size of uncompressed JWE: 303
    // original text from compressed JWE: 
    // Live long and prosper.
    // Live long and prosper.
    // Live long and prosper.
    // Live long and prosper.
    // 
    // original text from uncompressed JWE: 
    // Live long and prosper.
    // Live long and prosper.
    // Live long and prosper.
    // Live long and prosper.
    // 

    sbPlainText.DisposeStringBuilder()
    jwe.DisposeJwe()
    jweProtHdr.DisposeJsonObject()
    sbJweCompressed.DisposeStringBuilder()
    sbJweUncompressed.DisposeStringBuilder()
    jwe2.DisposeJwe()
    sbOriginalText.DisposeStringBuilder()