Sodium

Sodium is a modern, easy-to-use software library for encryption, decryption, signatures, password hashing, and more. It's a part of the broader Libsodium project, which is a portable, cross-platform fork of the NaCl (Networking and Cryptography Library) project. Sodium is designed to be fast, secure, and straightforward to use, even for those who are not cryptography experts.

It offers state-of-the-art cryptographic algorithms which are chosen for their strong security properties and resistance to attacks. These include algorithms like ChaCha20 for encryption, Poly1305 for message authentication, Curve25519 for key exchange, and Ed25519 for digital signatures.

Sodium has a user-friendly API that abstracts the complexity of cryptographic operations, making it accessible for developers with varying levels of expertise in cryptography. The library is optimized for speed without compromising security. It's suitable for performance-critical applications.

Libsodium works across multiple platforms, including Windows, macOS, and various Unix-like systems, making it a versatile choice for a wide range of applications. Sodium is suitable for a variety of applications, including securing network communication, encrypting files, authenticating messages, and securely hashing passwords.

It provides functions for encrypting and decrypting data, ensuring confidentiality. Sodium can be used to implement secure communication protocols, both for client-server models and peer-to-peer setups. It allows for the creation and verification of digital signatures, ensuring data integrity and non-repudiation.

Sodium offers robust password hashing functions, which are essential for securely storing user passwords.

Starting with PHP 7.2, Sodium became a core extension of PHP, reflecting its importance and utility in modern web development. This integration allows PHP developers to easily use Sodium's cryptographic capabilities in their applications without needing to install additional libraries.

In PHP, using Sodium might look something like this:

// Key pair generation for asymmetric encryption
$keypair = sodium_crypto_box_keypair();

// Public and secret keys extraction
$publicKey = sodium_crypto_box_publickey($keypair);
$secretKey = sodium_crypto_box_secretkey($keypair);

// Encrypting a message
$nonce = random_bytes(SODIUM_CRYPTO_BOX_NONCEBYTES);
$message = 'This is a secret message.';
$encrypted = sodium_crypto_box($message, $nonce, $keypair);

// Decrypting the message
$decrypted = sodium_crypto_box_open($encrypted, $nonce, $keypair);