检查字符串是否为MD5哈希

I accidentally stopped hashing passwords before they were stored, so now my database has a mix of MD5 Passwords and unhashed passwords.

我不小心在存储之前停止了散列密码，所以现在我的数据库混合了MD5密码和未散列的密码。

I want to loop through and hash the ones that are not MD5. Is it possible to check if a string is an MD5 hash?

我想循环并散列不是MD5的那些。是否可以检查字符串是否是MD5哈希？

2 个解决方案

#1

You can check using the following function:

您可以使用以下功能进行检查：

function isValidMd5($md5 ='')
{
    return preg_match('/^[a-f0-9]{32}$/', $md5);
}

echo isValidMd5('5d41402abc4b2a76b9719d911017c592');

The MD5 (Message-digest algorithm) Hash is typically expressed in text format as a 32 digit hexadecimal number.

MD5（消息摘要算法）哈希通常以文本格式表示为32位十六进制数。

This function checks that:

该函数检查：

1. It contains only letters and digits (a-z, 0-9).
2. 它只包含字母和数字（a-z，0-9）。
3. It's 32 characters long.
4. 它长32个字符。

#2

Maybe a bit faster one:

也许快一点：

function isValidMd5($md5 ='') {
  return strlen($md5) == 32 && ctype_xdigit($md5);
}