I am planning to build a password manager in dart / flutter. For in app search reasons I would need to decrypt any data and store that and the master password in memory for the duration of the user session (they will be cleared as soon as the user is no longer on the app). Is that safe? the only issue would be the third party accessing the memory while the user is on the application, but I'm not sure how possible and easy that is.
I could use keystore/keychain and request the data when I need to access it (for search that would not make a huge difference). The only issue with this is the efficiency and the numerous number of keychain requests
Target OS: iOS, Android and maybe Mac and Windows and Web in the future
Any thoughts about this?