secure random
#################


JAVA: secure random 概要 
======================================

new SecureRandom() 之后，如果直接调用nextBytes，默认使用SecureRandom对象(例如/dev/urandom)自身做为seed。

setSeed是往当前seed数组增补内容，而非替换。

因此，不要在SecureRandom之后直接调用setSeed设置可预测/固定seed。

可以考虑先SecureRandom，再nextBytes，再setSeed。

参考资料
=========

- `Random Numbers <https://wiki.openssl.org/index.php/Random_Numbers>`_
- `Is intel's RdRand TRNG or PRNG? <https://stackoverflow.com/questions/27653736/is-intels-rdrand-trng-or-prng>`_
- `Pseudorandom number generator <https://en.wikipedia.org/wiki/Pseudorandom_number_generator>`_
- `The Right Way to Use SecureRandom <https://tersesystems.com/blog/2015/12/17/the-right-way-to-use-securerandom/>`_
- `SecureRandom <https://developer.android.com/reference/java/security/SecureRandom.html>`_
- `Insufficient cryptographic randomness <https://www.computest.nl/advisories/CT-2019-0704_spring-security.txt>`_
- `Class SecureRandom <https://docs.oracle.com/javase/7/docs/api/java/security/SecureRandom.html>`_
- `SecureRandom漏洞解析 <http://www.droidsec.cn/securerandom%E6%BC%8F%E6%B4%9E%E8%A7%A3%E6%9E%90/>`_