| KAuth | Abstraction to system policy and authentication features | Security, API | LGPLv2.1+ | |
| KDESU | Integration with su for elevated privileges | Security, Desktop | LGPLv2.1+ | |
| kQOAuth | OAuth 1.0 authentication | Security, API | LGPLv2.1+ | |
| KWallet Framework | Secure and unified container for user passwords | Security | LGPLv2.1+ | |
| LXQt Wallet | Secure storage of data in an internal storage system or in KDE KWallet or GNOME libsecret | Security | BSD | |
| O2 | A library encapsulating OAuth 1.0 and 2.0 client authentication flows | Security, Bindings | Simplified BSD License | |
| QCA | Qt Cryptographic Architecture | Security | LGPLv2.1+ | |
| QOAuth | Library for OAuth authorization scheme | Security, API | LGPL | |
| Qt Certificate Addon | Qt Certificate Addon | Security | LGPLv2.1 | |
| QtKeychain | Platform-independent Qt API for storing passwords securely | Security | BSD-2 |