Database encryption and decryption

You can use database encryption to make it more difficult for someone to decipher the data in your database. You can choose to secure your database either with simple or with strong encryption.

• Simple encryption and strong encryption
  
• Database encryption methods
  
• Comparison of CREATE ENCRYPTED DATABASE and CREATE ENCRYPTED FILE statements
  You should use the CREATE ENCRYPTED DATABASE statement when you have an existing database that you want to encrypt. Use CREATE ENCRYPTED FILE statement only in the case where you have a database you want to encrypt that requires recovery.
• Creating an encrypted database (SQL)
  You can encrypt a database during creation by using the ENCRYPTED clause with the CREATE DATABASE statement.
• Creating an encrypted database (iqinit utility)
  You can create an encrypted database using the iqinit utility.
• Creating an encrypted copy of an existing database (SQL)
  You can create an encrypted copy of a database by using the CREATE ENCRYPTED DATABASE statement. This statement creates a copy of the file (in this case, in encrypted form), and does not overwrite the original database file.
• Decrypting a database (SQL)
  You can decrypt a database using the CREATE DECRYPTED DATABASE statement. This statement creates a copy of the file (in decrypted form) and does not overwrite the original database file.
• Encryption keys
  It is best to choose an encryption key value that cannot be easily guessed. The key can be of arbitrary length, but generally the longer the key, the better because a shorter key is easier to guess than a longer one. As well, including a combination of numbers, letters, and special characters decreases the chances of someone guessing the key.
• Security and performance issues
  Performance of SAP Sybase IQ is slower when the database is encrypted. The performance impact depends on how often pages are read from or written to disk, and can be minimized by ensuring that the server is using an adequate cache size.
• Column and table encryption
  If you only want to encrypt portions of your database, you can choose to encrypt columns or tables.