Tác dụng của hàm sha1()
The sha1() function calculates the sha1 (Secure Hash Algorithm 1) hash of a string.
This function calculates the sha1 hash of string using the US Secure Hash Algorithm 1, and returns that hash. To calculate the sha1 hash of a file, use the sha1_file() function.
The following table summarizes the technical details of this function.
| Return Value: | Returns the sha1 hash on success, or FALSE on failure. |
|---|---|
| Version: | PHP 4.3.0+ |
Warning: Using the sha1() function to secure passwords is not recommended, due to the fast nature of this hashing algorithm. Use the password_hash() function to hash passwords.
Syntax
The basic syntax of the sha1() function is given with:
The following example shows the sha1() function in action.
Example
Run this code »<?php
// Sample string
$str = "Blackbird";
// Calculating the hash
echo sha1($str);
?>Parameters
The sha1() function accepts the following parameters.
| Parameter | Description |
|---|---|
| string | Required. Specifies the input string. |
| raw_format | Optional. If set to true, it returns the hash in raw binary format with a length of 20. Default value is false which returns the hash as a 40-character hexadecimal number. |
More Examples
Here're some more examples showing how sha1() function actually works:
The following example calculates the sha1 hash in different formats.
Example
Run this code »<?php
// Sample string
$str = "Blackbird";
// Calculating the hash
echo "SHA1 hash as a 40-character hexadecimal number: ".sha1($str)."<br>";
echo "SHA1 hash in 20-character raw binary format: ".sha1($str, TRUE);
?>The following example checks whether the two sha1 hashes are identical or not.
Example
Run this code »<?php
// Sample string
$str = "Blackbird";
// Test if two hashes are Identical
if(sha1($str) === "3d822d44b2c8f36565435a5134cf7aec391732fe"){
echo "Blackbirds typically like to sing after rain.";
}
?>