说明：  Secure Socket Layer (SSL) and Transport Layer Security (TLS) are the current standards for communicating information securely over the internet. With TLS, all data being transmitted from point A to point B is encrypted. What if we only want some of our data to be encrypted as it is transmitted? We can use XML Encryption. 2. Each time something is encrypted, it must have the <EncryptedData > tags around it along with information as to what is being encrpted (text, an XML element, content of an element, etc). It also needs to have the <CipherData> tags and the <CipherValue> tags to indicate the actual encrypted data.