Symmetric encryption is the type of encryption that uses the same key for encryption and decryption. SQL Server allows you to choose from several algorithms, including DES, Triple DES, TRIPLE_DES_3KEY, RC2, RC4, 128-bit RC4, DESX, 128-bit AES, 192-bit AES, and 256-bit AES.
No single algorithm is ideal for all situations. However, the following general principles apply:
- Strong encryption requires more CPU resources
- Long keys generally yield stronger encryption than short keys
- Asymmetric encryption is stronger than symmetric encryption if using the same key size; but performance is compromised
- Long and strong passwords are better than short and/or weak passwords
- If you are encrypting large amounts of data, you should encrypt using a symmetric key because of performance issues
- Encrypted data cannot be compressed, but compressed data can be encrypted
When a symmetric key is created, it must be encrypted by using at least one of the following:
- Certificate
- Password
- Symmetric key
- Asymmetric...