Subpar PBKDF2 performance

[LinusU]

Running the PBKDF2 function on my Android phone using Conceal is considerably slower than the WebCrypto implementation on the very same phone:

Implementation	Speed
Conceal	~35,800 ms
BouncyCastle	~10,200 ms
WebCrypto	~2,380 ms

Code:

Conceal

byte[] salt = ...;
byte[] password = ...;

PBKDF2Hybrid encryptionKeyGenerator = new PBKDF2Hybrid();
encryptionKeyGenerator.setIterations(500000);
encryptionKeyGenerator.setSalt(salt, 0, salt.length);
encryptionKeyGenerator.setKeyLengthInBytes(256);
encryptionKeyGenerator.setPassword(password, 0, password.length);

byte[] derived = encryptionKeyGenerator.generate();

BouncyCastle

byte[] salt = ...;
byte[] password = ...;

PKCS5S2ParametersGenerator gen = new PKCS5S2ParametersGenerator(new SHA256Digest());
gen.init(password, salt, 500000);

byte[] derived = ((KeyParameter) gen.generateDerivedParameters(256)).getKey();

WebCrypto

const password = new Uint8Array(11)
const salt = new Uint8Array(16)

// populate password & salt

const key = await crypto.subtle.importKey('raw', password.buffer, { name: 'PBKDF2' }, false, ['deriveBits'])
const result = await crypto.subtle.deriveBits({ name: 'PBKDF2', salt: salt.buffer, iterations: 500000, hash: { name: 'SHA-256' } }, key, 256)