Encryption is a CPU-intensive operation that may introduce a performance overhead to your application in terms of CPU usage and the elapsed time of commands that use encrypted columns. The amount of overhead depends on the number of CPUs and Adaptive Server engines, the load on the system, the number of concurrent sessions accessing the encrypted data, and the number of encrypted columns referenced in a query. The encryption key size and the length of the encrypted data are also factors. In general, the larger the key size and the wider the data, the higher the CPU usage in the encryption operation.
The elapsed time depends on whether the Adaptive Server optimizer can make use of an encrypted column.
