Bug 277601 – WebCrypto PBKDF2 API is not optimized

• Component: WebCore Misc.
• Status: NEW

[zjc]

Safari's PBKDF2 performance is not optimized, here's a comparison with Chrome and FastPBKDF2:

```js
async function pbkdf2(algo) {
  const pwd = crypto.getRandomValues(new Uint8Array(16))
  const k = await crypto.subtle.importKey('raw', pwd, 'PBKDF2', false, ['deriveBits'])
  console.time(algo)
  const buf = await crypto.subtle.deriveBits({
    iterations: 8388608,
    salt: new Uint8Array(0),
    name: 'PBKDF2',
    hash: algo,
  }, k, 256)
  console.timeEnd(algo)
}
pbkdf2('SHA-256')
pbkdf2('SHA-512')
```

FastPBKDF2:

```bash
https://github.com/ctz/fastpbkdf2
cd fastpbkdf2
make
./bench 23
```

Benchmark result (MacBookPro M1):

|            | SHA256 (ms) | SHA512 (ms) |
|------------|-------------|-------------|
| Safari     |    1287     |    4816     |
| Chrome     |    827      |    2855     |
| FastPBKDf2 |    580      |    1610     |

PBKDF2 is the only API in the Web that allows for a specified cost, so efficiency is very important. Higher performance means that passwords can be iterated more times in the same amount of time, and the attacker has a higher cost to crack.

I hope that FastPBKDF2 or similar optimizations will be adopted so that more CPU resources can be used for cryptographic calculations instead of meaningless overhead.

[Radar WebKit Bug Importer]

<rdar://problem/133624956>