Solana Encryption

Solana employs the Edwards-curve Digital Signature Algorithm (EdDSA), an elliptical signature algorithm for cryptography.

info

K2 is a fork of Solana, so messages can also be encrypted using Koii addresses!

Helper Functions

Create two helper functions to help encode a message and decode data using TextEncoder and TextDecoder, respectively.

• TextEncoder — An interface that takes in a stream of code points as input and emits a stream of UTF-8 bytes.
• TextDecoder — An interface that represents a decoder for a specific text encoding, such as UTF-8, ISO-8859-2, etc.

// Encode message
const encode = (message) => {
  const encoder = new TextEncoder();
  const messageUint8 = encoder.encode(message); // Takes a string and returns a Uint8Array

  return messageUint8;
};

// Decode data
const decode = (data) => {
  const decoder = new TextDecoder();
  const decodedMessage = decoder.decode(data); // Returns a string containing the text decoded

  return decodedMessage;
};

Sign and Verify Message

A keypair's primary function is to sign messages and enable signature verification. Verification of a signature ensures that the data was signed by the owner of a specific private key.

• sign() — Signs the message using the secretKey and returns a signature.
• verify() — Verifies the message's signature and returns true if it was successful or false if it was unsuccessful.

To do this, we will use the TweetNaCl library.

const nacl = require("tweetnacl");

// Sign Message
function sign(message, secretKey) {
  const encodedMessage = encode(message); // Encode message using helper function
  const signature = nacl.sign.detached(encodedMessage, secretKey);

  return signature;
}

// Verify Message
function verify(message, signature, publicKey) {
  const encodedMessage = encode(message); // Encode message using helper function
  const verified = nacl.sign.detached.verify(
    encodedMessage,
    signature,
    publicKey
  );

  return verified;
}

Encrypt Message

Encode the message using the encode() helper function and then encrypt and authenticate encoded message using nacl.box().

nacl.box() Parameters

• message — The encoded message
• nonce — The given nonce
• publicKeyB — Peer's public key
• privateKeyA — Our secret key (private key)

Returns an encrypted and authenticated message.

// Encrypt Message
const encrypt = (message, nonce, publicKeyB, privateKeyA) => {
  const messageUint8 = encode(message); // Encode message

  //encrypt and authenticate encoded message
  const encrypted = nacl.box(messageUint8, nonce, publicKeyB, privateKeyA);

  return encrypted;
};

Decrypt Message

Use nacl.box.open() to authenticate and decrypt the given box with the peer's public key, our secret key, and the given nonce.

nacl.box.open() Parameters

• encrypted — The given box
• nonce — The given nonce
• publicKeyA — Peer's public key
• privateKeyB — Our secret key (private key)

Returns the original message, or null if authentication fails.

// Decrypt Message
const decrypt = (encrypted, nonce, publicKeyA, privateKeyB) => {
  const decrypted = nacl.box.open(encrypted, nonce, publicKeyA, privateKeyB); // Authenticate and decrypt
  const decryptedMessage = decode(decrypted); // Decode message

  return decryptedMessage;
};