Hi
what is exactly the purpose of sha1_file function, how the string it returns
is useful ?I've tried to understand the example which has been given in the manual but i am unable to get through it,can anybody explain in simple words?

Hi,

Did u have an idea of US Secure Hash Algorithm 1. ?????


US Secure hash algorithm 1


The US secure hash algorithm 1: "sha-1 produces a 160-bit output called a message digest.

The message digest can then, for example, be input to a signature algorithm which generates or verifies the signature for the message.


Signing the message digest rather than the message often improves the efficiency of the process because the message digest is usually much smaller in size than the message.

The same hash algorithm must be used by the verifier of a digital signature as was used by the creator of the digital signature."

the sha1_file() function calculates the sha-1 hash of a file..

It uses the us secure hash algorithm 1.

syntax :sha1_file(file,raw)

I'll give u an example....

<?php

$sha1file = file_get_contents("sha1file.txt");

if (sha1_file("test.txt") == $sha1file)

{

echo "Hello,Welcome to geekinterview.com";

}
else
{

echo "Goodbye";
}

?>

The output of the code above could be: Hello,Welcome to geekinterview.com

I think its enough to resolve u r query, if any .... Let me know...

Thanks & Regards,

Riju.

Hi,
Thanks for you help Riju.I have some basic idea about US secure hashing Algorithm,maybe i haven't explained my querry proerly before,but still you reply was of gr8 help.
If i m not wrong, sha1_file can be used to check whether a file has been downloaded properly or not?...
below, i m quoting some simple code,the filename given as parameter, is a webpage i have downloaded and saved on my desktop.




$sha1_val1 =sha1(.../sha1_test.htm"));
$sha1_val2 =sha1_file(".../sha1_test.htm");

echo $sha1_val1."<br>";
echo $sha1_val2."<br>";


if($sha1_val1==$sha1_val2)
{
print "file contents matched<br>"; }

else
{
print "file contents did not match<br>";
}

Above code is working fine and shows that file contents match.I just want you to tell me whether i m doing correctly(logically) or not?, Is this the way we can check whether file has been downloaded correctly or is there another method.

Thanks for your help,
Regards,

Saara

Hi,

Yes U r correct.

It's a simple method & the the code also works fine .So it can be used to chek whether a file has been downloaded correctly or not.
Just Go a head...

If any pblm we all r here to help u out.

Regards,
Riju.