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What Themis is

Themis is an open-source high-level cryptographic services library for securing data during authentication, storage, messaging, network exchange, etc. Themis solves 90% of typical data protection use cases that are common for most apps.

Themis helps to build both simple and complex cryptographic features easily, quickly, and securely. Themis allows developers to focus on the main thing: developing their applications.

Use cases that Themis solves

• Encrypt stored secrets in your apps and backend: API keys, session tokens, files.

• Encrypt sensitive data fields before storing in database ("application-side field-level encryption").

• Support searchable encryption, data tokenization and data masking using Themis and Acra.

• Exchange secrets securely: share sensitive data between parties, build simple chat app between patients and doctors.

• Build end-to-end encryption schemes with centralised or decentralised architecture: encrypt data locally on one app, use it encrypted everywhere, decrypt only for authenticated user.

• Maintain real-time secure sessions: send encrypted messages to control connected devices from your app, receive real-time sensitive data from your apps to your backend.

• Compare secrets between parties without revealing them (zero-knowledge proof-based authentication).

• One cryptographic library that fits them all: Themis is the best fit for multi-platform apps (e.g., iOS+Android+Electron app with Node.js backend) because it provides 100% compatible API and works in the same way across all supported platforms.

Cryptosystems

Themis provides ready-made building blocks (“cryptosystems”) which simplify usage of core cryptographic security operations.

Themis provides 4 important cryptographic services:

• Secure Cell: a multi-mode cryptographic container suitable for storing anything from encrypted files to database records and format-preserved strings. Secure Cell is built around AES-256-GCM, AES-256-CTR.