我应该使用什么列类型/长度来在数据库中存储 Bcrypt 哈希密码?

2021-11-20 00:00:00 hash types storage mysql bcrypt

我想在数据库中存储散列密码(使用 BCrypt).什么是好的类型，哪个是正确的长度?使用 BCrypt 散列的密码是否总是长度相同?

I want to store a hashed password (using BCrypt) in a database. What would be a good type for this, and which would be the correct length? Are passwords hashed with BCrypt always of same length?

编辑

示例哈希:

$2a$10$KssILxWNR6k62B7yiX0GAe2Q7wwHlrzhF3LqtVvpyvHZf0MwvNfVu

在对一些密码进行散列后，BCrypt 似乎总是生成 60 个字符的散列.

After hashing some passwords, it seems that BCrypt always generates 60 character hashes.

编辑 2

抱歉没有提到实现.我正在使用 jBCrypt.

Sorry for not mentioning the implementation. I am using jBCrypt.

推荐答案

bcrypt 的模块化 crypt 格式包括

The modular crypt format for bcrypt consists of

  • $2$、$2a$ 或 $2y$ 标识 散列算法和格式
  • 表示成本参数的两位数值，后跟 $
  • 一个 53 个字符长的 base-64 编码值(它们使用字母 .、/、0–9, A–Z, a–z 与标准 Base 64 编码 字母表)包括:
    • salt 的 22 个字符(实际上只有 132 个解码位中的 128 个位)
    • 31 个字符的加密输出(实际上只有 186 个解码位中的 184 个位)
    • $2$, $2a$ or $2y$ identifying the hashing algorithm and format
    • a two digit value denoting the cost parameter, followed by $
    • a 53 characters long base-64-encoded value (they use the alphabet ., /, 0–9, A–Z, a–z that is different to the standard Base 64 Encoding alphabet) consisting of:
      • 22 characters of salt (effectively only 128 bits of the 132 decoded bits)
      • 31 characters of encrypted output (effectively only 184 bits of the 186 decoded bits)

      因此总长度分别为 59 或 60 字节.

      Thus the total length is 59 or 60 bytes respectively.

      当您使用 2a 格式时，您将需要 60 个字节.因此对于 MySQL，我建议使用 CHAR(60) BINARY 或 BINARY(60)(参见 _bin 和 binary 排序规则 以了解区别).

      As you use the 2a format, you’ll need 60 bytes. And thus for MySQL I’ll recommend to use the CHAR(60) BINARYor BINARY(60) (see The _bin and binary Collations for information about the difference).

      CHAR 不是二进制安全的，相等性不仅取决于字节值，还取决于实际的排序规则；在最坏的情况下，A 被视为等于 a.参见 _bin 和 <代码>二进制排序规则了解更多信息.

      CHAR is not binary safe and equality does not depend solely on the byte value but on the actual collation; in the worst case A is treated as equal to a. See The _bin and binary Collations for more information.

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