Blog : PHP md5() Function

PHP md5() Function

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 Complete PHP String Reference
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Definition and Usage
The md5() function calculates the MD5 hash of a string.

The md5() function uses the RSA Data Security, Inc. MD5 Message-Digest Algorithm.

From RFC 1321 - The MD5 Message-Digest Algorithm: "The MD5 message-digest algorithm takes as input a message of arbitrary length and produces as output a 128-bit "fingerprint" or "message digest" of the input. The MD5 algorithm is intended for digital signature applications, where a large file must be "compressed" in a secure manner before being encrypted with a private (secret) key under a public-key cryptosystem such as RSA."

This function returns the calculated MD5 hash on success, or FALSE on failure.

Syntax
md5(string,raw)  

Parameter Description
string Required. The string to be calculated
raw Optional. Specifies hex or binary output format:
TRUE - Raw 16 character binary format
FALSE - Default. 32 character hex number
Note: This parameter was added in PHP 5.0
 


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Example 1
$str = "Hello";
echo md5($str);
?>  

The output of the code above will be:

8b1a9953c4611296a827abf8c47804d7  


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Example 2
In this example we will print the result of md5() and then test it:

$str = "Hello";
echo md5($str);

if (md5($str) == '8b1a9953c4611296a827abf8c47804d7')
  {
  echo "
Hello world!";
  exit;
  }
?>  

The output of the code above will be:

8b1a9953c4611296a827abf8c47804d7
Hello world!