Question: Does Memcached support encryption?

Answer

By default, Memcached doesn't support encryption natively. However, there are several ways to encrypt data stored in Memcached.

1. Encrypting data before storing it in Memcached

One way to encrypt data is by encrypting it using an encryption library like OpenSSL and then storing the encrypted data in Memcached. When retrieving the data, decrypt it using the same encryption library.

Here's an example of how to use OpenSSL to encrypt and decrypt data:

import OpenSSL
import memcache

key = b"my_secret_key"
value = b"My secret value"

# Encrypt the value
cipher = OpenSSL.crypto.Cipher(alg="aes_256_cbc", key=key, iv=b"0")
encrypted_value = cipher.update(value) + cipher.final()

# Store the encrypted value in Memcached
mc = memcache.Client(["127.0.0.1:11211"])
mc.set("my_key", encrypted_value)

# Retrieve the encrypted value from Memcached and decrypt it
encrypted_value = mc.get("my_key")
cipher = OpenSSL.crypto.Cipher(alg="aes_256_cbc", key=key, iv=b"0", op=OpenSSL.crypto.DECRYPT_MODE)
decrypted_value = cipher.update(encrypted_value) + cipher.final()

2. Using a proxy server

Another way to encrypt data is by using a proxy server like Stunnel or Nginx, which can act as an SSL/TLS termination point for Memcached clients. The proxy server can encrypt the data sent from the client to the server and vice versa.

Here's an example of how to set up Stunnel to encrypt data for Memcached:

1. Install Stunnel: apt-get install stunnel4

2. Create a new configuration file /etc/stunnel/memcached.conf with the following contents:

   [memcached]
   client = yes
   accept = 127.0.0.1:11212
   connect = 127.0.0.1:11211
   

3. Start Stunnel: service stunnel4 start

4. Configure your Memcached client to use the encrypted port 11212 instead of the default port 11211.

3. Using a specialized client library

There are some Memcached client libraries that support encryption natively, like python-memc-encryption and Spymemcached. These libraries allow you to encrypt data before sending it to the server and decrypt it when retrieving it.

Here's an example of how to use python-memc-encryption to encrypt and decrypt data:

from pymemcache.client.base import Client
from memcachecrypt import Encryptor, Decryptor

key = b"my_secret_key"
value = b"My secret value"

# Create an encryptor and a decryptor
encryptor = Encryptor(key)
decryptor = Decryptor(key)

# Create a Memcached client with encryption support
mc = Client(("localhost", 11211), serializer=encryptor, deserializer=decryptor)

# Store the encrypted value in Memcached
mc.set("my_key", value)

# Retrieve the encrypted value from Memcached and decrypt it
decrypted_value = mc.get("my_key")

Note that using encryption can increase the CPU overhead of your Memcached server and reduce performance. Therefore, it's important to benchmark your system and adjust your configuration accordingly.