58 lines
1.8 KiB
JavaScript
58 lines
1.8 KiB
JavaScript
"use strict";
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import tweetnacl from 'tweetnacl';
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const { randomBytes, secretbox } = tweetnacl;
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/**
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* Creates a new key ready for encryption.
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* @return {string} A new base64-encoded key.
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*/
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function make_key() {
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return Buffer.from(randomBytes(secretbox.keyLength)).toString("base64");
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}
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/**
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* Encrypts the given data with the given key.
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* @param {string} key The base64-encoded key to use to encrypt the data.
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* @param {string} data The data to encrypt.
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* @return {string} The encrypted data, base64 encoded.
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*/
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function encrypt(key, data) {
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const key_bytes = Buffer.from(key, "base64");
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const nonce = randomBytes(secretbox.nonceLength);
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const data_bytes = Buffer.from(data, "utf-8");
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const cipher_bytes = secretbox(data_bytes, nonce, key_bytes);
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const concat_bytes = Buffer.concat([nonce, cipher_bytes]);
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key_bytes.fill(0);
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nonce.fill(0);
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return Buffer.from(concat_bytes).toString("base64");
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}
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/**
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* Decrypts the given data with the given key.
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* @param {string} key The base64-encoded keyto use to decrypt the data.
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* @param {string} cipher_text The base64-encoded ciphertext to decrypt.
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* @return {string} The decoded data, utf-8 encoded.
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*/
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function decrypt(key, cipher_text) {
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const concat_bytes = Buffer.from(cipher_text, "base64");
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const key_bytes = Buffer.from(key, "base64");
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const nonce = concat_bytes.slice(0, secretbox.nonceLength);
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const cipher_bytes = concat_bytes.slice(secretbox.nonceLength);
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const data_bytes = secretbox.open(cipher_bytes, nonce, key_bytes);
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// Failed to decrypt message. Could be because the nonce, key, or ciphertext is invalid
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// Ref https://github.com/dchest/tweetnacl-js/blob/master/test/04-secretbox.quick.js
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// Ref https://github.com/dchest/tweetnacl-js/wiki/Examples#secretbox
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if(!data_bytes) return null;
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return Buffer.from(data_bytes).toString("utf-8");
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}
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export { make_key, encrypt, decrypt };
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