Symmetric encryption
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...
