数据索引的最佳哈希算法（即crc）(Best hash algorithm for a data index (ie, crc))

数据索引的最佳哈希算法（即crc）(Best hash algorithm for a data index (ie, crc))

基本上，我正在跟踪文件修改，例如：

array ( 'crc-of-file' => 'latest-file-contents' )

这是因为我在运行时同时处理不同文件的文件内容。

所以，问题是，我应该在文件内容上使用什么哈希算法（作为字符串，因为文件正在被加载）？

防止碰撞是至关重要的，也是至关重要的。 到目前为止，我没有看到任何安全隐患。

编辑：我可以使用的另一件事而不是散列内容是文件修改时间戳，但我不确定它是多么可靠。 另一方面，我认为监控所述邮票比每次散列文件更快。

Basically, I'm keeping track of file modifications, in something like:

array ( 'crc-of-file' => 'latest-file-contents' )

This is because I'm working on the file contents of different files at runtime at the same time.

So, the question is, what hashing algorithm should I use over the file contents (as a string, since the file is being loaded anyway)?

Collision prevention is crucial, as well as performance. I don't see any security implications in this so far.

Edit: Another thing I could have used instead of hashing contents is the file modification timestamp, but I wasn't sure how reliable it is. On the other hand, I think it's faster to monitor the said stamp than hashing the file each time.

最满意答案

CRC它不是哈希算法，也不是校验和算法，所以你的碰撞几率会很高。

md5非常快，碰撞风险对于您的应用/体积来说相当小。 如果要缓冲文件，您可能还希望使用hash扩展来查看增量散列 。

有点复杂，但也值得一看（如果你有的话）是Inotify扩展 。

CRC it's not a hashing algorithm, a checksum algorithm so your chances of collision will be quite high.

md5 is quite fast and the collision risk is rather minimal for your kind of application / volume. If you are buffering the file, you may also want to look at incremental hashes using the hash extension.

A bit more complex, but also worth looking at (if you have it) is the Inotify extension.