PHP 的 password_hash()：public 一次性盐与私人固定盐
PHP's password_hash(): public one-time salt vs. private fixed salt
PHP password_hash() (http://php.net/manual/en/function.password-hash.php) 手册说：
The used algorithm, cost and salt are returned as part of the hash. Therefore, all information that's needed to verify the hash is included in it.
我的问题是：为什么？
我在另一个 SO 答案中读到这个：(Static Salt vs Random Salt - Security PHP)
Random salts have a tremendous benefit. If all accounts in the system use the same salt, an attacker can brute-force calculate hashes for that salt and break into all accounts with just one computational run.
我明白了。但是，password_hash() 将盐嵌入到返回的哈希值中，我认为它是 public，因此攻击者知道每个密码的盐。
换个长私盐不是更好吗？
我能想到的一件事是，使用相同的盐创建的散列对于相同的密码来说是相同的，并且可能允许攻击者通过对数据库中散列的统计分析取得进展。
然而，这可以通过使用私有哈希字典而不是仅使用一个字典来缓解，但是在 PHP 7.password_hash() 中，这不再可能。
我不是安全专家，我相信 PHP 人知道他们在做什么，所以我很高兴听到为什么 password_hash() 方式被认为是正确的方法。
我找到了这个答案：
http://php.net/manual/en/function.password-hash.php#114410
if you thought "why is the salt included in the hash and is it save
when i store it as it is in my db?"
Answer i found: The salt just has to be unique. It not meant to be a
secret.
As mentioned in notes and docu before: let password_hash() take care
of the salt.
With the unique salt you force the attacker to crack the hash. The
hash is unique and cannot be found at rainbow tables.
PHP password_hash() (http://php.net/manual/en/function.password-hash.php) 手册说：
The used algorithm, cost and salt are returned as part of the hash. Therefore, all information that's needed to verify the hash is included in it.
我的问题是：为什么？
我在另一个 SO 答案中读到这个：(Static Salt vs Random Salt - Security PHP)
Random salts have a tremendous benefit. If all accounts in the system use the same salt, an attacker can brute-force calculate hashes for that salt and break into all accounts with just one computational run.
我明白了。但是，password_hash() 将盐嵌入到返回的哈希值中，我认为它是 public，因此攻击者知道每个密码的盐。
换个长私盐不是更好吗？
我能想到的一件事是，使用相同的盐创建的散列对于相同的密码来说是相同的，并且可能允许攻击者通过对数据库中散列的统计分析取得进展。
然而，这可以通过使用私有哈希字典而不是仅使用一个字典来缓解，但是在 PHP 7.password_hash() 中，这不再可能。
我不是安全专家，我相信 PHP 人知道他们在做什么，所以我很高兴听到为什么 password_hash() 方式被认为是正确的方法。
我找到了这个答案：
http://php.net/manual/en/function.password-hash.php#114410
if you thought "why is the salt included in the hash and is it save when i store it as it is in my db?"
Answer i found: The salt just has to be unique. It not meant to be a secret.
As mentioned in notes and docu before: let password_hash() take care of the salt.
With the unique salt you force the attacker to crack the hash. The hash is unique and cannot be found at rainbow tables.