shiro加密底层

protected byte[] hash(byte[] bytes, byte[] salt, int hashIterations) throws UnknownAlgorithmException {
    MessageDigest digest = this.getDigest(this.getAlgorithmName());
    if (salt != null) {
        digest.reset();
        digest.update(salt);
    }

    byte[] hashed = digest.digest(bytes);
    int iterations = hashIterations - 1;

    for(int i = 0; i < iterations; ++i) {
        digest.reset();
        hashed = digest.digest(hashed);
    }

    return hashed;
}