List_ultimate/app/composables/crypto.ts

import sodium from "libsodium-wrappers"

export type KeyPair = {
  publicKey: Uint8Array
  privateKey: Uint8Array
}

export type EncryptedPayload = {
  nonce: Uint8Array
  cipher: Uint8Array
}

export type EncryptedPrivateKey = {
  nonce: Uint8Array
  cipher: Uint8Array
  salt: Uint8Array
}

export const useCryptoStore = () => {

  let ready = false

  const init = async (): Promise<void> => {
    if (!ready) {
      await sodium.ready
      ready = true
    }
  }

  /**
   * USER KEY PAIR
   */
  const generateUserKeyPair = (): KeyPair => {

    const pair = sodium.crypto_box_keypair()

    return {
      publicKey: pair.publicKey,
      privateKey: pair.privateKey
    }
  }

  /**
   * MASTER KEY
   */
  const generateMasterKey = (): Uint8Array => {
    return sodium.randombytes_buf(
      sodium.crypto_secretbox_KEYBYTES
    )
  }

  /**
   * ENCRYPT PRIVATE KEY
   */
  const encryptPrivateKey = (
    privateKey: Uint8Array,
    masterKey: Uint8Array
  ): EncryptedPayload => {

    const nonce = sodium.randombytes_buf(
      sodium.crypto_secretbox_NONCEBYTES
    )

    const cipher = sodium.crypto_secretbox_easy(
      privateKey,
      nonce,
      masterKey
    )

    return { nonce, cipher }
  }

  /**
   * DECRYPT PRIVATE KEY
   */
  const decryptPrivateKey = (
    encrypted: EncryptedPayload,
    masterKey: Uint8Array
  ): Uint8Array => {

    return sodium.crypto_secretbox_open_easy(
      encrypted.cipher,
      encrypted.nonce,
      masterKey
    )
  }

  /**
   * LIST KEY
   */
  const generateListKey = (): Uint8Array => {

    return sodium.randombytes_buf(
      sodium.crypto_aead_xchacha20poly1305_ietf_KEYBYTES
    )
  }

  /**
   * ENCRYPT LIST DATA
   */
  const encryptList = (
    data: string,
    listKey: Uint8Array
  ): EncryptedPayload => {

    const nonce = sodium.randombytes_buf(
      sodium.crypto_aead_xchacha20poly1305_ietf_NPUBBYTES
    ) 

    const cipher = sodium.crypto_aead_xchacha20poly1305_ietf_encrypt(
      sodium.from_string(data),
      null,
      null,
      nonce,
      listKey
    )

    return { nonce, cipher }
  }

  /**
   * DECRYPT LIST DATA
   */
  const decryptList = (
    encrypted: EncryptedPayload,
    listKey: Uint8Array
  ): string => {

    const decrypted = sodium.crypto_aead_xchacha20poly1305_ietf_decrypt(
      null,
      encrypted.cipher,
      null,
      encrypted.nonce,
      listKey
    )

    return sodium.to_string(decrypted)
  }

  /**
   * ENCRYPT LIST KEY FOR USER
   */
  const encryptListKeyForUser = (
    listKey: Uint8Array,
    recipientPublicKey: Uint8Array,
    senderPrivateKey: Uint8Array
  ): EncryptedPayload => {

    const nonce = sodium.randombytes_buf(
      sodium.crypto_box_NONCEBYTES
    )

    const cipher = sodium.crypto_box_easy(
      listKey,
      nonce,
      recipientPublicKey,
      senderPrivateKey
    )

    return { nonce, cipher }
  }

  /**
   * DECRYPT LIST KEY
   */
  const decryptListKey = (
    encrypted: EncryptedPayload,
    senderPublicKey: Uint8Array,
    recipientPrivateKey: Uint8Array
  ): Uint8Array => {

    return sodium.crypto_box_open_easy(
      encrypted.cipher,
      encrypted.nonce,
      senderPublicKey,
      recipientPrivateKey
    )
  }

  return {

    init,

    generateUserKeyPair,

    generateMasterKey,

    encryptPrivateKey,
    decryptPrivateKey,

    generateListKey,

    encryptList,
    decryptList,

    encryptListKeyForUser,
    decryptListKey
  }
}