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128位可逆加密器/哈希器以减小数据库大小

[英]128 bit reversible encryptor/hasher to reduce DB size

原文 2016-09-07 09:31:07 5 2 php/ mysql/ encryption/ hash/ md5

Is there anything out there for PHP that can hash/encrypt a long string into a 128 bit string that can also be reversed? PHP是否可以将长字符串哈希/加密为也可以反转的128位字符串？

I am trying importing hundreds on millions of strings into a MySQL DB and the average string is over 100 characters, MD5 gets this down to 32 characters which significantly reduces storage however I cannot reverse this again in my application. 我正在尝试将数以亿计的字符串导入MySQL数据库，平均字符串超过100个字符，MD5将其降至32个字符，这大大减少了存储空间，但是我无法在应用程序中再次将其反转。

Does PHP have anything available that can handle this? PHP是否有任何可用的方法可以解决此问题？

2 个解决方案

If I understand your question correctly, it seems to me you mix up hashing and compression quite a lot. 如果我正确理解了您的问题，在我看来，您将哈希和压缩混为一谈。

Most hash-functions are not easily reversible, because that is not their purpose. 大多数哈希函数不容易逆，因为这不是它们的目的。 There are infinite "Strings/ByteStreams/Numbers/..." that correspond to the result of a hash-function. 有无限的“字符串/字节流/数字/ ...”对应于哈希函数的结果。 As you may know, even images that are a few Gigabytes big, also give you an md5sum of 32 characters. 如您所知，即使是几千兆字节的图像，也会给您带来32个字符的md5sum。

You can not just magically map any String into a String of fixed length that is shorter, to just be able to magically pouff it back to its original String. 您不仅可以将任何String神奇地映射到较短长度的固定长度的String中，还可以神奇地将其返回原来的String中。

It may well be, that some hash-functions could very efficiently be used to reverse their process if you know that your target results have to have this and that property (in you case maybe character-length of 100-120), but I doubt it. 如果您知道目标结果必须具有该属性和该属性（在您的情况下，字符长度为100-120），则很有可能将某些哈希函数有效地用于逆转其过程。它。

Or do I totally misunderstand and you just mean ASCII-Strings with the expression "128 bit string"? 还是我完全误解了，您只是用表达式“ 128位字符串”来表示ASCII字符串？

不，您不能这样做：鸽洞原理