Highlights on Java Script Encryption Technique

Javascript Web Encryption Technique is one of the ways how to show encrypted data in the form of JSON data structures. It provides the data structure to encrypt a plain text. The structure consists of mainly three things. Before going into detail, firstly we must have a knowledge of what is Plain Text and what is Cipher Text?

So, Plaintext is bytes to be encrypted and CipherText is the encrypted version of the plain text.  Content Encryption Key is the symmetric key generated to encrypt the plaintext for the user to produce the Ciphertext, which is encrypted to the user as the JWE Encrypted Key.

1) JWE Header:- This represents JSON object that describes the encryption operations which are applied to create JWE Ciphertext, which is return to the user as an encrypted text.

2) JWE Encrypted Key:-  It is encrypted with a key and the output is recorded as the byte array, which is called as the Javascript Web Encryption.

3) JWE CipherText:-   A byte array containing the ciphertext.

JWE represents encrypted content using data JSON structures and base64. The three parts which JWE contains are base64url-encoded and are enclosed in order separated by period ( . ) character.

{"alg":"RSA1_5",
 "enc":"A256GCM",
 "iv":"__79_Pv6-fg",
 "x5t":"7noOPq-hJ1_hCnvWh6IeYI2w9Q0"}

In above example is:- 

a) The Content Encryption Key is encrypted using RSA-PKCS1_1.5 algorithm to produce Encrypted Key.

b) The Plaintext is encrypted using the AES-256-GCM algorithm.

c) The specified 64-bit initialization Vector with the base64.

With all the conversion it will lead to some alphanumeric code key 

eyJhbGciOiJSU0ExXzUiLA0KICJlbmMiOiJBMjU2R0NNIiwNCiAiaXYiOiJfXzc5
X1B2Ni1mZyIsDQogIng1dCI6Ijdub09QcS1oSjFfaENudldoNkllWUkydzlRMCJ9

With this Content Encryption Key, we will convert a plain text to cipher text and using the recepient's key to encrypt the CEK (Content Encryption Key) to produce the JWE (Javascript Web Encryption). 

To conclude, we can use this technique to encrypt our crucial data being expose over the network.