带有JSON帖子的Golang编码/解码base64不起作用

I build a client and a server in golang both are using this functions to encrypt/decrypt

func encrypt(text []byte) ([]byte, error) {
    block, err := aes.NewCipher(key)
    if err != nil {
        return nil, err
    }
    b := base64.StdEncoding.EncodeToString(text)
    ciphertext := make([]byte, aes.BlockSize+len(b))
    iv := ciphertext[:aes.BlockSize]
    if _, err := io.ReadFull(rand.Reader, iv); err != nil {
        return nil, err
    }
    cfb := cipher.NewCFBEncrypter(block, iv)
    cfb.XORKeyStream(ciphertext[aes.BlockSize:], []byte(b))
    return ciphertext, nil
}

func decrypt(text []byte) ([]byte, error) {
    block, err := aes.NewCipher(key)
    if err != nil {
        return nil, err
    }
    if len(text) < aes.BlockSize {
        return nil, errors.New("ciphertext too short")
    }
    iv := text[:aes.BlockSize]
    text = text[aes.BlockSize:]
    cfb := cipher.NewCFBDecrypter(block, iv)
    cfb.XORKeyStream(text, text)
    data, err := base64.StdEncoding.DecodeString(string(text))
    if err != nil {
        return nil, err
    }
    return data, nil
}

so yeah I make a normal post request

url := "https://"+configuration.Server+configuration.Port+"/get"

// TODO maybe bugs rest here
ciphertext, err := encrypt([]byte(*getUrl))
if err != nil {
    fmt.Println("Error: " + err.Error())
}
fmt.Println(string(ciphertext))

values := map[string]interface{}{"url": *getUrl, "urlCrypted": ciphertext}
jsonValue, _ := json.Marshal(values)
jsonStr := bytes.NewBuffer(jsonValue)

req, err := http.NewRequest("POST", url, jsonStr)

and the servercode is as following

requestContent := getRequestContentFromRequest(req)
url := requestContent["url"].(string)

undecryptedUrl := requestContent["urlCrypted"].(string)
decryptedurl, err := decrypt([]byte(undecryptedUrl))
if err != nil {
    fmt.Println("Error: " + err.Error())
}
fmt.Println(decryptedurl)

where getRequestContentFromRequest is as following

func getRequestContentFromRequest(req *http.Request)                 
    map[string]interface{} {
    buf := new(bytes.Buffer)
    buf.ReadFrom(req.Body)
    data := buf.Bytes()
    var requestContent map[string]interface{}
    err := json.Unmarshal(data, &requestContent)
    if err != nil {
        fmt.Println(err)
    }
    return requestContent
}

Now to the problem. If I encrypt my string in the client and decrypt it direct after that everything is fine.

But, when I send the encrypted string to the server and try to decrypt it with literrally the same function as in the client, the decrypt function throws an error.

Error: illegal base64 data at input byte 0

I think the Problem is the unmarshalling of the JSON.

Thanks for help.

P.S.

Repos are

github.com/BelphegorPrime/goSafeClient and github.com/BelphegorPrime/goSafe

UPDATE

Example JSON

{"url":"facebook2.com","urlCrypted":"/}\ufffd\ufffd\ufffdgP\ufffdN뼞\ufffd\u0016\ufffd)\ufffd\ufffd\ufffdy\u001c\u000f\ufffd\ufffd\ufffdep\ufffdY\ufffd\ufffd$\ufffd\ufffd"}

UPDATE2

I made a playground here