On iOS, a keychain is a sort of encrypted container where users can store their data and passwords. On OS X users can limit the access of the keychain to particular applications and users. On iOS every app has its keychain and only that particular application will have access. This ensures that the data is secure and inaccessible to others. Keychains should only be used to store small pieces of data for example passwords. On iOS, an app can use this through (Keychain services API) this will provide function numbers for data manipulation which is stored in the app keychain.
- Sec Item Add, this is the function which is used for item addition to app keychain
- Sec Item Copy Matching is the function to find an item of keychain owned by the application
- Sec Item Delete is the function that will delete an item from app keychain
- Sec Item Update will update an item in the app keychain
Check out this article too:How To Protect Your iOS Based Device
This API service is a C API and all the above mentioned functions accepts a dictionary that is CFDictionary that contains class key pair and also attribute key value pairs.
Encryption and decryption
There are two types of encryption, which are symmetric and other is asymmetric. Symmetric encryption only uses one shared key for both encryption and decryption. Asymmetric uses two different keys for encryption, but they are related for decryption. Symmetric encryption and keychain services API can be used for encryption on iOS. Users can also encrypt their data with RNCryptor. It is a library and also a very good choice for encrypting and decrypting data. This project is used by several developers and is also actively maintained by its developers. The main features of the library include CBC mode, AES-256 encryption, Random IV, password stretching, Encrypt –and then-hash HMAC. This is the way by which you can encrypt and decrypt data on iOS. By this way you can safely secure your credentials using app keychain. Whether the data is useful or not it is important that you keep it secure so that no other can take advantage of your data.