Sealed Messages

Use Shamir's secret sharing with @wharfkit/antelope Public/Private Keys to encrypt and decrypt a message.

In a real world scenario, the sender of the message needs to have a private key and known the public key of the receiver. They then take their message and a nonce to encode the message using the sealMessage function. The receiver needs to take the message and decrypt it with their private key, the public key of the sender, as well as the nonce of the message.

As a full example below, we will use the following information.

Sender

Public: PUB_K1_7DcFftmP6xfsvuycjX9ZXU5fxoF9Dwft1K3Amymze5n5f6zj4W
Private: PVT_K1_2Uew3LyC8KRRXrnqiN4RmMP2nqR1tVY5gAjXMJkdtFVTthdRtJ

Receiver

Public: PUB_K1_5BSU51h332xWvhXYnu9TSvKQV3C9QDxS9XK1coq9m6zBnZwHKn
Private: PVT_K1_LzT8YiEeLKG82uYqYPjytVotkztTVgR9Xs9YFfRU1wQ7dtcED

Encrypt a message with a senders private key, the receivers public key, and a nonce.

const from = PrivateKey.from('PVT_K1_2Uew3LyC8KRRXrnqiN4RmMP2nqR1tVY5gAjXMJkdtFVTthdRtJ')
const to = PublicKey.from('PUB_K1_5BSU51h332xWvhXYnu9TSvKQV3C9QDxS9XK1coq9m6zBnZwHKn')
const nonce = UInt64.from(1234567890)
const message = 'Hello, World!'

const sealedMessage = await sealMessage(message, from, to, nonce)

console.log(String(sealedMessage))

// Output: abb3a412f59211df4d9d984d445127a9

The encrypted message can then be relayed to the receiver. The receiver can decrypt the message now using the their own private key, the senders public key, and the nonce.

const encrypted = 'abb3a412f59211df4d9d984d445127a9'
const sealedMessage = Bytes.from(encrypted, 'hex')
const from = PublicKey.from('PUB_K1_7DcFftmP6xfsvuycjX9ZXU5fxoF9Dwft1K3Amymze5n5f6zj4W')
const to = PrivateKey.from('PVT_K1_LzT8YiEeLKG82uYqYPjytVotkztTVgR9Xs9YFfRU1wQ7dtcED')
const nonce = UInt64.from(1234567890)

const unsealedMessage = await unsealMessage(sealedMessage, to, from, nonce)

console.log(unsealedMessage)
// Output: Hello, World!