盐和密码 - 前缀或后缀
This is a question about salting phrases that need to be hashed.
I was wondering if it more secure to prefix the salt to a phrase or postfix it?
salt + phrase or
phrase + salt
My question comes from this comment on this post on MD5s. I am not sure I understand the reasoning behind the author's comment.
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盐加在前面还是后面都没有区别。
但以下因素将影响安全性。
Whether the salt is appended to the front or the back makes no difference.
The following factors will affect security though
当有人对盐的使用有疑问时，我担心这是因为他们正忙于（重新）发明他们本来就不应该发明的东西。 根据这个问题，我的建议是使用 HMAC。
When someone has a question about the use of salts I fear it is because they are busy (re)inventing things they really shouldn't be in the first place. Based on the question my recommendation is to use an HMAC.
当你消化盐时并不重要：前缀、后缀、中缀都会产生不同的哈希值，但达到了击败彩虹表或其他预哈希字典攻击的相同目的。
我认为该评论与 MD5 中的漏洞有关，而不是一般的散列。 我不明白细节，但它 与查找产生相同哈希值的两个前缀有关.
It doesn't matter when you digest the salt: prefix, postfix, infix all produce different hashes, but achieve the same purpose of defeating rainbow tables or other pre-hashed dictionary attacks.
I think that the comment has to do specifically with a vulnerability in MD5, not hashing in general. I don't understand the details, but it has to do with finding two prefixes that produce the same hash.
与其他人所说的不同，这确实很重要！ 如果你愿意的话，可以使用@einstein 的方式来使用
HMAC。为什么前缀不好，因为可以计算到给定固定盐前缀的校验和的中间状态。 然后开始并行计算其余部分。 总之，
phrase+salt比salt+phrase更安全，但HMAC(salt,phrase)甚至更好。相关阅读
unlike what others said, it does matter! and as @einstein if you care use
HMAC.why prefix is bad, because one can calculate the intermediate state of the checksum up to the given fixed salt prefix. then start calculating the rest in parallel. In summary
phrase+saltis more secure thansalt+phrase, butHMAC(salt, phrase)is even better.related reading
从技术上讲，这并不重要，只要盐是唯一的并且不容易被猜到即可。 只是不要像我一样犯储存盐的错误。
对字符串进行“加盐”的目的是通过比 MD5 哈希更加个性化和独特的方式对其进行加扰。 这样做的方法没有正确或错误之分，只要您是唯一知道它是如何工作的人即可。 无论哪种方式都会达到结果，即使生成的 MD5 哈希值不与彩虹表对应，从而轻松破解密码。
Technically it doesn't matter, so long as the salt is unique and not easily guessable. Just don't make the mistake of storing the salt, like I did.
The purpose of "salting" a string is to scramble it in a way a bit more personal and unique than an MD5 hash will do. There's no right or wrong way to do it, just so long as you're the only one that knows how it works. It will achieve the result either way, which is to make the MD5 hashes generated not correspond with a rainbow table for easy cracking of passwords.