Encrypted Plain-Text Note Apps

Joplin is an open-source, cross-platform note-taking application designed for secure, private knowledge management. It functions as a local-first productivity platform, maintaining a complete relational database on the user's device to ensure offline availability and high-performance data retrieval. The application prioritizes data sovereignty by implementing an end-to-end encryption layer, which secures all information locally with a master key before any synchronization occurs. The platform distinguishes itself through a delta-based synchronization engine that transmits only specific file c

Laverna is an open-source note-taking application designed as a privacy-focused alternative to Evernote. It operates as a single-page application that runs entirely in the browser, combining Markdown editing with client-side encryption to ensure note content is encrypted on the device before it ever reaches a server or cloud storage. The application distinguishes itself through its offline-first architecture, storing notes locally using browser storage for full offline access and editing capabilities. It synchronizes notes across devices through a unified interface that connects to multiple b

Notable is a local-first markdown note taking application and document manager. It functions as a personal knowledge base that persists notes as plain text files on the local disk to ensure data portability and user ownership. The application provides a markdown editor featuring a split-pane live preview for real-time rendering of content, including mathematical expressions and diagrams. Information is organized through a hierarchical tagging system that allows for nested labels and multi-dimensional categorization. The software includes tools for bulk note management to apply operations acr

libsignal is a cryptographic library that implements the Signal Protocol, providing the core primitives for end-to-end encrypted messaging with forward secrecy and deniable authentication. It includes the Double Ratchet algorithm for iteratively deriving fresh encryption keys per message, and the X3DH key agreement protocol for establishing shared secrets between parties asynchronously. A session state machine maintains cryptographic state across message exchanges, supporting recovery and out-of-order delivery. The library extends beyond basic messaging encryption with capabilities such as ze

CryptPad is a self-hosted, zero-knowledge office suite designed for real-time collaborative editing and content management. It provides a privacy-centric infrastructure where documents, files, and notes are encrypted in the browser before transmission, ensuring that the server administrator cannot access the underlying data. The platform implements zero-knowledge user authentication, utilizing cryptographic keys to verify identities so that plain text passwords are never stored on the server. To further isolate sensitive operations, the system employs a security architecture that separates th

Linsa.io is an end-to-end encrypted cloud storage service and zero-knowledge data vault. It functions as a private content sharing platform that encrypts files and data on the client side, ensuring only the owner can access the stored content. The project employs a local-first approach, processing data updates and encryption on the local device before syncing encrypted blobs to a remote persistence layer. It uses a zero-knowledge architecture where the service provider cannot access decryption keys or view the plaintext content of stored files. The platform provides capabilities for private

OpenKeychain is a mobile OpenPGP key manager and identity provider used for storing, importing, and organizing encryption keys and digital certificates. It serves as an end-to-end encryption client and digital signature tool for encrypting and decrypting text and files. The application functions as a central vault that provides encryption and decryption services to third-party apps, such as email clients and password managers. It enables secure public key exchange through online directory retrieval and QR code scanning. The project covers cryptographic identity verification, including the ab

Seafile is a self-hosted file synchronization and sharing platform that provides a central server for maintaining file consistency across multiple devices. It functions as a cloud storage management system and a collaborative document suite, integrating tools for real-time teamwork and shared file management. The platform distinguishes itself through a metadata-driven file organizer that uses extensible properties and hierarchical tags instead of traditional folder structures. It includes client-side encrypted storage to protect private data using user-defined passwords before files leave the

Upspin is a decentralized naming and storage system that provides an end-to-end encrypted file system. It assigns every user a unique identity and organizes files within a global, permissioned namespace where data is encrypted on the client before transmission. The system separates identity resolution from data storage using a public-key identity provider and a key-server architecture. This allows for decentralized identity management and the resolution of usernames to specific directory and storage server addresses. The project includes a hierarchical access control system that manages read

Signal-Desktop is a cross-platform messaging application that provides end-to-end encrypted communication. It implements the Signal Protocol to secure messages and voice calls, ensuring that only intended recipients can access content. The application manages asynchronous key exchange and session initialization to maintain secure communication channels between parties who are not online simultaneously. The project distinguishes itself through advanced cryptographic protections, including hybrid post-quantum security that combines classical elliptic curve cryptography with lattice-based algori

anytype-ts is a TypeScript client library and offline-first knowledge base client designed for managing structured layouts and modular blocks within a private distributed database. It functions as a zero-knowledge data synchronizer and schema-driven API wrapper that enables the secure replication of encrypted data across devices. The library utilizes peer-to-peer connectivity and zero-knowledge encryption to ensure data remains private and unreadable to hosting infrastructure. It employs a schema-driven approach to compile data definitions into typed language bindings, ensuring consistent com