@hackbg/miscreant-esm/src/mac/cmac.dist.mjs

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

import Block from "../internals/block.dist.mjs";
import {xor} from "../internals/xor.dist.mjs";
export class CMAC {
  _cipher;
  _subkey1;
  _subkey2;
  static async importKey(provider, keyData) {
    const cipher = await provider.importBlockCipherKey(keyData);
    const subkey1 = new Block();
    await cipher.encryptBlock(subkey1);
    subkey1.dbl();
    const subkey2 = subkey1.clone();
    subkey2.dbl();
    return new CMAC(cipher, subkey1, subkey2);
  }
  _buffer;
  _bufferPos = 0;
  _finished = false;
  constructor(_cipher, _subkey1, _subkey2) {
    this._cipher = _cipher;
    this._subkey1 = _subkey1;
    this._subkey2 = _subkey2;
    this._buffer = new Block();
  }
  reset() {
    this._buffer.clear();
    this._bufferPos = 0;
    this._finished = false;
    return this;
  }
  clear() {
    this.reset();
    this._subkey1.clear();
    this._subkey2.clear();
  }
  async update(data) {
    const left = Block.SIZE - this._bufferPos;
    let dataPos = 0;
    let dataLength = data.length;
    if (dataLength > left) {
      for (let i = 0; i < left; i++) {
        this._buffer.data[this._bufferPos + i] ^= data[i];
      }
      dataLength -= left;
      dataPos += left;
      await this._cipher.encryptBlock(this._buffer);
      this._bufferPos = 0;
    }
    while (dataLength > Block.SIZE) {
      for (let i = 0; i < Block.SIZE; i++) {
        this._buffer.data[i] ^= data[dataPos + i];
      }
      dataLength -= Block.SIZE;
      dataPos += Block.SIZE;
      await this._cipher.encryptBlock(this._buffer);
    }
    for (let i = 0; i < dataLength; i++) {
      this._buffer.data[this._bufferPos++] ^= data[dataPos + i];
    }
    return this;
  }
  async finish() {
    if (!this._finished) {
      const subkey = this._bufferPos < Block.SIZE ? this._subkey2 : this._subkey1;
      xor(this._buffer.data, subkey.data);
      if (this._bufferPos < Block.SIZE) {
        this._buffer.data[this._bufferPos] ^= 0x80;
      }
      await this._cipher.encryptBlock(this._buffer);
      this._finished = true;
    }
    return this._buffer.clone().data;
  }
}