md5

(PHP 4, PHP 5, PHP 7, PHP 8)

md5 — 计算字符串的 MD5 散列值

警告

由于此函数依赖的算法已不足够复杂,不推荐使用此函数对明文密码加密。详细内容参见这里。

说明

function md5(string $string, bool $binary = false ): string

使用 » RSA 数据安全公司的 MD5 消息摘要算法计算 string 的 MD5 散列值,并返回该散列值。

参数

string: 要计算的字符串。
binary: 如果可选的 binary 被设置为 true ,那么 md5 摘要将以 16 字符长度的原始二进制格式返回。

返回值

以 32 字符的十六进制数形式返回散列值。

示例

示例 #1 md5() 示例

<?php
$str = 'apple';
if (md5($str) === '1f3870be274f6c49b3e31a0c6728957f') {
 echo "Would you like a green or red apple?";
}
?>

参见

hash() - 生成散列值(消息摘要)
password_hash() - 创建密码的散列(hash)

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用户贡献的备注 2 notes

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yiminrong at yahoo dot ca ¶

5 years ago

Regarding Ray Paseur's comment, the strings hash to:
0e462097431906509019562988736854
0e830400451993494058024219903391
The odds of getting a hash exactly matching the format /^0+e[0-9]+$/ are not high but are also not negligible.
It should be added as a general warning for all hash functions to always use the triple equals === for comparison.
Actually, the warning should be in the operators section when comparing string values! There are lots of warnings about string comparisons, but nothing specific about the format /^0+e[0-9]+$/.

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Ray.Paseur sometimes uses Gmail ¶

7 years ago

md5('240610708') == md5('QNKCDZO')
This comparison is true because both md5() hashes start '0e' so PHP type juggling understands these strings to be scientific notation. By definition, zero raised to any power is zero.