refactor(core): Migrate from crypto-js to native crypto (#7556)

[`crypto-js` has been
discontinued](1da3dabf93)

PS: We'll remove `crypto-js` usage from `n8n-workflow` and
`@n8n_io/license-sdk` in separate PRs.

packages/core/src/Cipher.ts

@@ -1,21 +1,43 @@
 import { Service } from 'typedi';
-import { AES, enc } from 'crypto-js';
+import { createHash, createCipheriv, createDecipheriv, randomBytes } from 'crypto';
 import { InstanceSettings } from './InstanceSettings';
 
+// Data encrypted by CryptoJS always starts with these bytes
+const RANDOM_BYTES = Buffer.from('53616c7465645f5f', 'hex');
+
 @Service()
 export class Cipher {
 	constructor(private readonly instanceSettings: InstanceSettings) {}
 
 	encrypt(data: string | object) {
-		const { encryptionKey } = this.instanceSettings;
-		return AES.encrypt(
-			typeof data === 'string' ? data : JSON.stringify(data),
-			encryptionKey,
-		).toString();
+		const salt = randomBytes(8);
+		const [key, iv] = this.getKeyAndIv(salt);
+		const cipher = createCipheriv('aes-256-cbc', key, iv);
+		const encrypted = cipher.update(typeof data === 'string' ? data : JSON.stringify(data));
+		return Buffer.concat([RANDOM_BYTES, salt, encrypted, cipher.final()]).toString('base64');
 	}
 
 	decrypt(data: string) {
+		const input = Buffer.from(data, 'base64');
+		if (input.length < 16) return '';
+		const salt = input.subarray(8, 16);
+		const [key, iv] = this.getKeyAndIv(salt);
+		const contents = input.subarray(16);
+		const decipher = createDecipheriv('aes-256-cbc', key, iv);
+		return Buffer.concat([decipher.update(contents), decipher.final()]).toString('utf-8');
+	}
+
+	private getKeyAndIv(salt: Buffer): [Buffer, Buffer] {
 		const { encryptionKey } = this.instanceSettings;
-		return AES.decrypt(data, encryptionKey).toString(enc.Utf8);
+		const password = Buffer.concat([Buffer.from(encryptionKey, 'binary'), salt]);
+		const hash1 = createHash('md5').update(password).digest();
+		const hash2 = createHash('md5')
+			.update(Buffer.concat([hash1, password]))
+			.digest();
+		const iv = createHash('md5')
+			.update(Buffer.concat([hash2, password]))
+			.digest();
+		const key = Buffer.concat([hash1, hash2]);
+		return [key, iv];
 	}
 }