multi-layers-encryption/src/index.ts

Encryption and decryption with multiple configurable layers

import crypto from "crypto";

export type LayerConfig = {
  algorithm: string; // เช่น 'aes-256-cbc', 'aes-192-cbc', 'des-ede3-cbc'
  key: string;
  salt?: string;
};

export class MultiLayerEncryption {
  private layers: LayerConfig[];

  constructor(layers: LayerConfig[]) {
    this.layers = layers;
  }

  encrypt(content: string): string {
    let result = content;

    for (const layer of this.layers) {
      const iv = layer.salt
        ? Buffer.from(layer.salt.padEnd(16, "0").slice(0, 16))
        : crypto.randomBytes(16);

      const key = crypto
        .createHash("sha256")
        .update(layer.key)
        .digest()
        .subarray(0, this.getKeyLength(layer.algorithm));

      const cipher = crypto.createCipheriv(layer.algorithm, key, iv);
      let encrypted = cipher.update(result, "utf8", "base64");
      encrypted += cipher.final("base64");

      result = JSON.stringify({
        algorithm: layer.algorithm,
        iv: iv.toString("base64"),
        data: encrypted,
      });
    }

    return result;
  }

  decrypt(content: string): string {
    let result = content;

    for (let i = this.layers.length - 1; i >= 0; i--) {
      const layer = this.layers[i];
      const parsed = JSON.parse(result);

      const iv = Buffer.from(parsed.iv, "base64");
      const key = crypto
        .createHash("sha256")
        .update(layer.key)
        .digest()
        .subarray(0, this.getKeyLength(layer.algorithm));

      const decipher = crypto.createDecipheriv(
        layer.algorithm,
        key,
        iv
      );
      let decrypted = decipher.update(parsed.data, "base64", "utf8");
      decrypted += decipher.final("utf8");

      result = decrypted;
    }

    return result;
  }

  private getKeyLength(algorithm: string): number {
    if (algorithm.includes("256")) return 32;
    if (algorithm.includes("192")) return 24;
    if (algorithm.includes("128")) return 16;
    if (algorithm.includes("des-ede3")) return 24; // 3DES
    return 16; // default
  }
}

export default MultiLayerEncryption;