Embed confidential information in items that you store in a keychain.
When you want to store a secret such as a password or cryptographic key, you package it as a keychain item. Along with the data itself, you provide a set of publicly visible attributes both to control the item’s accessibility and to make it searchable. As shown in Figure 1, keychain services handles data encryption and storage (including data attributes) in a keychain, which is an encrypted database stored on disk. Later, authorized processes use keychain services to find the item and decrypt its data.