note 109180 added to imagick.getimagesignature

The getImageSignature function for the ImageMagick package in PHP returns only the SHA-1 hash value for an image. There are not any other algorithms available for it within the ImageMagick package, but fortunately, this is PHP and you have a wide array of hashing algorithms to use on any image file. The function hash_algos() will return an array of hashing algorithms available in PHP and the function hash_file() will take three parameters (one for the algorithm to use, one for the filename, and an optional variable for binary output). Instead of being limited to the SHA-1 algorithm of the getImageSignature function, you could use SHA-256, SHA-384, SHA-512, Whirlpool, HAVAL, Salsa, Gost, Adler32, CRC32, or MD5, among others and variations of these. However, the SHA-1 result of the hash_file() function performed on a file does not return the same result as the SHA-1 of the getImageSignature() function. This leads me to believe that the SHA-1 of the getImageSignature() might be performed on the Imagick object itself, instead of the file, whereas the hash_file() function is clearly performed on the file itself. That's just a guess, though. Some sample code for the alternate hashing algorithm, with every algorithm performed on the image file : <?php // Author: holdoffhunger@gmail.com // Set File for Hashing Function // --------------------------------------------------- $filename_with_folder_for_hashing = "image_workshop/test_file.bmp"; // Acquire Dynamic Hashing Algorithm List // --------------------------------------------------- $php_dynamic_hash_algorithms = hash_algos(); // Count Dynamic Hashing Algorithm List // --------------------------------------------------- $number_of_dynamic_hash_algorithms = count($php_dynamic_hash_algorithms); // Parse Dynamic Hashing Algorithm List // --------------------------------------------------- for($i = 0; $i < $number_of_dynamic_hash_algorithms; $i++) { // Get Current Hashing Algorithm // --------------------------------------------------- $current_hashing_algorithm = $php_dynamic_hash_algorithms[$i]; // Perform Hashing on File // --------------------------------------------------- $current_hashing_algorithm_hex_result = hash_file($current_hashing_algorithm, $filename_with_folder_for_hashing, FALSE); // Print Hashed Results // --------------------------------------------------- print("$current_hashing_algorithm Algorithm ::: $current_hashing_algorithm_hex_result"); print("<br><br>"); } ?> Example Results: ........................... md2 Algorithm ::: 03205df9c6717d74f1f003c66f58e98a md4 Algorithm ::: b2a204a2e5c3968d2abd5dc372fbee10 md5 Algorithm ::: b9d92a61714b221d24c7730d4764ca82 sha1 Algorithm ::: 8db4c92346c26568b13ea43fbcf514e37942a41a (and so on for 34 more algorithms)... ---- Server IP: 69.147.83.197 Probable Submitter: 68.9.137.178 ---- Manual Page -- http://www.php.net/manual/en/imagick.getimagesignature.php Edit -- https://master.php.net/note/edit/109180 Del: integrated -- https://master.php.net/note/delete/109180/integrated Del: useless -- https://master.php.net/note/delete/109180/useless Del: bad code -- https://master.php.net/note/delete/109180/bad+code Del: spam -- https://master.php.net/note/delete/109180/spam Del: non-english -- https://master.php.net/note/delete/109180/non-english Del: in docs -- https://master.php.net/note/delete/109180/in+docs Del: other reasons-- https://master.php.net/note/delete/109180 Reject -- https://master.php.net/note/reject/109180 Search -- https://master.php.net/manage/user-notes.php