code: function aes(length) {
    const C = function(key) {
      const aes_ecb = new AES_ECB(key);
  
      this.encrypt = function(block) {
        return aes_ecb.encrypt(block);
      };
  
      this.decrypt = function(block) {
        return aes_ecb.decrypt(block);
      };
    };
  
    C.blockSize = C.prototype.blockSize = 16;
    C.keySize = C.prototype.keySize = length / 8;
  
    return C;
  }
docs: TODO use webCrypto or nodeCrypto when possible.