Update README.md V1

Initial draft for readme.md

README.md

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+## Overview
 
-## locker phases
-
-### phase 1
-working locker
-- configuration: pull configuration from toml file and environment variables
-- cards api: ability to perform add, retrieve, delete card actions
-- jwe + jws: encryption and signing middleware with keys passed in [`configuration`]
-- master key to be passed in configuration
-- key custodian: add support to decrypt the master key before starting the server
-
-### phase 2
-- tenant api for adding and deleting tenants
-- add support for *kms* encryption on the environment variables
-- adding logging and metrics for locker
-- tenant specific jwe public key storage and utilizing key_id for identification
-- docker + kubernetes setup for infra deployment
-
-### phase 3 (optional)
-- add support for key rotation
+The Hyperswitch Card Vault (Tartarus) is a highly performant and a secure vault to save sensitive data such as payment card details, bank account details etc. 
+
+It is designed in an polymorphic manner to handle and store any type of sensitive information making it highly scalable with extensive coverage of payment methods and processors.
+
+Tartarus is built with a GDPR compliant personal identifiable information (PII) storage and secure encryption algorithms to be fully compliant with PCI DSS requirements.
+
+Here's a quick guide to [Get Started](https://github.com/NishantJoshi00/tartarus/blob/main/docs/guides/setup.md) with setting up Tartarus.
+
+### How does Tartarus work?
+
+- Your application will communicate with Tartarus via a middleware. 
+- All requests and responses to and from the middleware are signed and encrypted with the JWS and JWE algorithms. 
+- The locker supports CRD APIs on the /data and /cards endpoints - <API Reference to be linked> 
+- Cards are stored against the combination of merchant and customer identifiers. 
+- Internal hashing checks are in place to avoid data duplication.
+
+![General Work Flow](https://drive.google.com/file/d/17zDZpVRIKd1r1WmgJL0HMyxIZCeZV_V1/view?usp=sharing)
+
+### Key Hierarchy
+
+- Master Key - AES generated key to that is encrypted/decrypted by the custodian keys to run the locker and associated configurations.
+- Custodian Keys - AES generated key that is used to encrypt and decrypt the master key. It broken into two keys (key 1 and key 2) and available with two custodians to enhance security.
+
+![Key Hierarchy](https://drive.google.com/file/d/1-kyrFL72nJ41lx2WTVvgH69_mUey3F4S/view?usp=sharing)
+
+### Setup Guide
+Follow this guide to setup Tartarus - [Get Started](https://github.com/NishantJoshi00/tartarus/blob/main/docs/guides/setup.md)