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byjg/crypto
===========

A cryptography library for symmetric encryption with an innovative keyless exchange mechanism.

6.0.0(7mo ago)19.5k↓18.9%MITPHPPHP >=8.3 <8.6CI failing

Since Apr 25Pushed 3mo ago1 watchersCompare

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   sidebar\_key crypto   tags    php

 cryptography

    Passwordless Cryptography Library
=================================

[](#passwordless-cryptography-library)

A cryptography library for symmetric encryption with an innovative keyless exchange mechanism.

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How it works
------------

[](#how-it-works)

The algorithm is well-known, but the major problem is HOW to store and exchange symmetric keys securely. This library solves this with an innovative "keyless" exchange mechanism:

### Key Seed Instead of Keys

[](#key-seed-instead-of-keys)

Instead of storing or transmitting actual encryption keys, this library uses a **key seed** - a list of 2-255 entries of 32 bytes each (the default is 32 entries). Both the sender and receiver must have the same key seed.

### Dynamic Key Generation with Scrolling Window

[](#dynamic-key-generation-with-scrolling-window)

For each encryption operation:

1. The library uses an 8-byte **scrolling window** to extract random portions from the key seed entries
2. A 4-byte **header** encodes the key seed entry indices and extraction offsets
3. The encrypted data includes this header (embedded in the payload)
4. The actual key and IV are **never stored or transmitted**

The scrolling window can extract 8 bytes from any position (0-24) within each 32-byte key seed entry, providing 25 possible positions per entry, resulting in millions of possible key/IV combinations.

### Keyless Decryption

[](#keyless-decryption)

When decrypting:

1. The 4-byte header is extracted from the encrypted payload
2. Using the same key seed and the header, the exact key and IV are **reconstructed** using the same offsets
3. The data is decrypted and authenticated

This means you can securely exchange encrypted data without ever transmitting the actual encryption keys - only a 4-byte header that's meaningless without the key seed!

Usage
-----

[](#usage)

```