@hackbg/miscreant-esm/src/stream.dist.mjs

(ESM port) Misuse resistant symmetric encryption library providing AES-SIV (RFC 5297), AES-PMAC-SIV, and STREAM constructions

import {AEAD} from "./aead.dist.mjs";
import {WebCryptoProvider} from "./providers/webcrypto.dist.mjs";
export const NONCE_SIZE = 8;
export const LAST_BLOCK_FLAG = 1;
export const COUNTER_MAX = 0xFFFFFFFF;
export class StreamEncryptor {
  static async importKey(keyData, nonce, alg, provider = new WebCryptoProvider()) {
    return new StreamEncryptor(await AEAD.importKey(keyData, alg, provider), nonce);
  }
  _aead;
  _nonce_encoder;
  constructor(aead, nonce) {
    this._aead = aead;
    this._nonce_encoder = new NonceEncoder(nonce);
  }
  async seal(plaintext, lastBlock = false, associatedData = new Uint8Array(0)) {
    return this._aead.seal(plaintext, this._nonce_encoder.next(lastBlock), associatedData);
  }
  clear() {
    this._aead.clear();
    return this;
  }
}
export class StreamDecryptor {
  static async importKey(keyData, nonce, alg, provider = new WebCryptoProvider()) {
    return new StreamDecryptor(await AEAD.importKey(keyData, alg, provider), nonce);
  }
  _aead;
  _nonce_encoder;
  constructor(aead, nonce) {
    this._aead = aead;
    this._nonce_encoder = new NonceEncoder(nonce);
  }
  async open(ciphertext, lastBlock = false, associatedData = new Uint8Array(0)) {
    return this._aead.open(ciphertext, this._nonce_encoder.next(lastBlock), associatedData);
  }
  clear() {
    this._aead.clear();
    return this;
  }
}
class NonceEncoder {
  buffer;
  view;
  array;
  counter;
  finished;
  constructor(noncePrefix) {
    if (noncePrefix.length !== NONCE_SIZE) {
      throw new Error(`STREAM: nonce must be 8-bits (got ${noncePrefix.length}`);
    }
    this.buffer = new ArrayBuffer(NONCE_SIZE + 4 + 1);
    this.view = new DataView(this.buffer);
    this.array = new Uint8Array(this.buffer);
    this.array.set(noncePrefix);
    this.counter = 0;
    this.finished = false;
  }
  next(lastBlock) {
    if (this.finished) {
      throw new Error("STREAM: already finished");
    }
    this.view.setInt32(8, this.counter, false);
    if (lastBlock) {
      this.view.setInt8(12, LAST_BLOCK_FLAG);
      this.finished = true;
    } else {
      this.counter += 1;
      if (this.counter > COUNTER_MAX) {
        throw new Error("STREAM counter overflowed");
      }
    }
    return this.array;
  }
}