Generate 128 Bit Key Php
Generating Keys for Encryption and Decryption.; 3 minutes to read +7; In this article. Creating and managing keys is an important part of the cryptographic process. Symmetric algorithms require the creation of a key and an initialization vector (IV). The key must be kept secret from anyone who should not decrypt your data. Feb 08, 2017 Specifically when dealing with the encryption and decryption of credentials within Powershell (next blog post), you will be dealing with AES keys to handle this securely. Notes AES encryption only supports 128-bit (16 bytes), 192-bit (24 bytes) or 256-bit key (32 bytes) lengths. Generate a random 128-bit key (k1), a random 128-bit IV, and a random salt (64 bits is probably sufficient). Use PBKDF2 to generate a 256-bit key from your password and the salt, then split that into two 128-bit keys (k2, k3). Make sure your algorithm's native output is at least 256 bits, or this will be slow. PBKDF2- SHA256 is a good choice. Feb 13, 2013 Generating a Software License Key String with PHP Feb 13, 2013 by Matt Posted in Coding 6 Comments I was working on a project recently that required unique API keys to be generated for clients connecting to the server. AES encryption/decryption in PHP. GitHub Gist: instantly share code, notes, and snippets. Skip to content. All gists Back to GitHub. // Generate a 256-bit.
For example, AES has 3 choices: 128-bit, 192-bit, // or 256-bit. In the ChaCha20 algorithm, the key size must always be 256-bits (32-bytes). // Both sides (encryptor and decryptor) must be in possession of the same secret key // in order to communicate. Whichever side generates the key, it must somehow // deliver the key to the other side. If set to TRUE, uniqid will add additional entropy (using the combined linear congruential generator) at the end of the return value, which increases the likelihood that the result will be unique. Return Values.
I was working on a project recently that required unique API keys to be generated for clients connecting to the server. For various reasons, I settled on the style of license key you commonly see for software packages. You know, the kind you always had to read off the back of a CD case and type in when installing the application. Like H8OV7-HNTB5-JLLOH-W8FG2
.
It’s fairly easy to write such a function. The basic idea is to loop around four times—once for each segment—and have a nested loop that runs five times, picking a random character each time. Here’s what I came up with:
The $tokens
string contains the characters that are valid in the key, so the loop can pick from it. The $segment_chars
and $num_segments
variables are the number of characters in a segment and the number of segments in the key, respectively. $key_string
is an empty string that the loop will add the characters into.
The first for loop runs four times, assuming the desired result is four segments in the key. The inner loop picks a character out of $tokens
at random each time it goes around. (PHP strings are also arrays, with the each character having its own numerical offset.) The characters are tacked onto the $segment
string.
Then the segment is joined with the $key_string
, and a dash character is applied if the loop isn’t on the final segment yet. End result: something like H8OV7-HNTB5-JLLOH-W8FG2
.
Generate 128 Bit Key Php Free
Now how can you make sure the key is unique when it’s generated?
Generate 128 Bit Key Php Code
You generate a new key string with the function, check to see if it exists in your database, and lather/rinse/repeat until that is no longer the case. Usually you won’t have collisions too often, so it will only need to run once. I’m too lazy to figure out the probability, but considering there are 52,521,875 possible combinations for one 5-character segment…you’re probably not going to run into performance issues anytime soon. And if you do, just add another segment onto your key strings.