Session Key Generation In Php
- Introduction
- Using The Session
- Adding Custom Session Drivers
Introduction
A session key is any encryption key used to symmetrically encrypt one communication session only. In other words, it's a temporary key that is only used once, during one stretch of time, for encrypting and decrypting data; future conversations between the two parties would be encrypted with different session keys. To generate an ECDH session key on the host with a DS28C36, the host must collect the Device Public Key, MANID, and page data from the DS28C36. As shown in Figure 6 the Device Public Key and Master Private Key are used to calculate a new shared point on the elliptic curve. Oct 02, 2003 For example, in generating a public-private key pair, you are asked some questions, like the your name, company name, location, state, etc. You can answer the questions the same every time, but have different key pair data. You can even tell someone the data, and they won't be able to generate your key. Jan 26, 2011 I could then call that with CURL from the PHP code when it needs to generate a brand new session ID, so that the session ID that is used will be accepted by ASP.NET. Completely replace the entire session module in our ASP.NET code with a custom session module. Jun 06, 2016 This video is part of the Udacity course 'Intro to Information Security'. Watch the full course at https://www.udacity.com/course/ud459.
Since HTTP driven applications are stateless, sessions provide a way to store information about the user across multiple requests. Laravel ships with a variety of session backends that are accessed through an expressive, unified API. Putty key generator download for windows 7 64 bit. Support for popular backends such as Memcached, Redis, and databases is included out of the box.
What’s the best way of generating a unique key, that can’t be guessed easily? I would like to create a unique key for both account activation and referral purposes, that includes a checksum to help prevent users from easily guessing other users activation or referral keys. Also, in PHP is it possible to create you own session key? Oct 04, 2018 Session handling is a key concept in PHP that enables user information to be persisted across all the pages of a website or app. In this post, you'll learn the basics of session handling in PHP. We'll start with an explanation of how sessions work and how they are related to cookies.
Configuration
The session configuration file is stored at config/session.php
. Be sure to review the options available to you in this file. By default, Laravel is configured to use the file
session driver, which will work well for many applications.
The session driver
configuration option defines where session data will be stored for each request. Laravel ships with several great drivers out of the box:
file
- sessions are stored instorage/framework/sessions
.cookie
- sessions are stored in secure, encrypted cookies.database
- sessions are stored in a relational database.memcached
/redis
- sessions are stored in one of these fast, cache based stores.array
- sessions are stored in a PHP array and will not be persisted.
{tip} The array driver is used during testing and prevents the data stored in the session from being persisted.
Driver Prerequisites
Database
When using the database
session driver, you will need to create a table to contain the session items. Below is an example Schema
declaration for the table:
You may use the session:table
Artisan command to generate this migration:
Redis
Before using Redis sessions with Laravel, you will need to either install the PhpRedis PHP extension via PECL or install the predis/predis
package (~1.0) via Composer. For more information on configuring Redis, consult its Laravel documentation page.
{tip} In the session
configuration file, the connection
option may be used to specify which Redis connection is used by the session.
Using The Session
Retrieving Data
There are two primary ways of working with session data in Laravel: the global session
helper and via a Request
instance. First, let's look at accessing the session via a Request
instance, which can be type-hinted on a controller method. Remember, controller method dependencies are automatically injected via the Laravel service container:
When you retrieve an item from the session, you may also pass a default value as the second argument to the get
method. This default value will be returned if the specified key does not exist in the session. If you pass a Closure
as the default value to the get
method and the requested key does not exist, the Closure
will be executed and its result returned:
The Global Session Helper
You may also use the global session
PHP function to retrieve and store data in the session. When the session
helper is called with a single, string argument, it will return the value of that session key. When the helper is called with an array of key / value pairs, those values will be stored in the session:
{tip} There is little practical difference between using the session via an HTTP request instance versus using the global session
helper. Both methods are testable via the assertSessionHas
method which is available in all of your test cases.
Retrieving All Session Data
If you would like to retrieve all the data in the session, you may use the all
method:
Determining If An Item Exists In The Session
To determine if an item is present in the session, you may use the has
method. The has
method returns true
if the item is present and is not null
:
To determine if an item is present in the session, even if its value is null
, you may use the exists
method. The exists
method returns true
if the item is present:
Storing Data
To store data in the session, you will typically use the put
method or the session
helper:
Pushing To Array Session Values
The push
method may be used to push a new value onto a session value that is an array. For example, if the user.teams
key contains an array of team names, you may push a new value onto the array like so:
Retrieving & Deleting An Item
The pull
method will retrieve and delete an item from the session in a single statement:
Session Key Generation In Php Login
Flash Data
Sometimes you may wish to store items in the session only for the next request. You may do so using the flash
method. Data stored in the session using this method will be available immediately and during the subsequent HTTP request. After the subsequent HTTP request, the flashed data will be deleted. Flash data is primarily useful for short-lived status messages:
If you need to keep your flash data around for several requests, you may use the reflash
method, which will keep all of the flash data for an additional request. If you only need to keep specific flash data, you may use the keep
method:
Deleting Data
The forget
method will remove a piece of data from the session. If you would like to remove all data from the session, you may use the flush
method:
Regenerating The Session ID
Regenerating the session ID is often done in order to prevent malicious users from exploiting a session fixation attack on your application.
Laravel automatically regenerates the session ID during authentication if you are using the built-in LoginController
; however, if you need to manually regenerate the session ID, you may use the regenerate
method.
Adding Custom Session Drivers
Implementing The Driver
Your custom session driver should implement the SessionHandlerInterface
. This interface contains just a few simple methods we need to implement. A stubbed MongoDB implementation looks something like this:
Key Generation Software
{tip} Laravel does not ship with a directory to contain your extensions. You are free to place them anywhere you like. In this example, we have created an Extensions
directory to house the MongoSessionHandler
.
Since the purpose of these methods is not readily understandable, let's quickly cover what each of the methods do:
- The
open
method would typically be used in file based session store systems. Since Laravel ships with afile
session driver, you will almost never need to put anything in this method. You can leave it as an empty stub. It is a fact of poor interface design (which we'll discuss later) that PHP requires us to implement this method. - The
close
method, like theopen
method, can also usually be disregarded. For most drivers, it is not needed. - The
read
method should return the string version of the session data associated with the given$sessionId
. There is no need to do any serialization or other encoding when retrieving or storing session data in your driver, as Laravel will perform the serialization for you. - The
write
method should write the given$data
string associated with the$sessionId
to some persistent storage system, such as MongoDB, Dynamo, etc. Again, you should not perform any serialization - Laravel will have already handled that for you. - The
destroy
method should remove the data associated with the$sessionId
from persistent storage. - The
gc
method should destroy all session data that is older than the given$lifetime
, which is a UNIX timestamp. For self-expiring systems like Memcached and Redis, this method may be left empty.
Registering The Driver
Once your driver has been implemented, you are ready to register it with the framework. To add additional drivers to Laravel's session backend, you may use the extend
method on the Session
facade. You should call the extend
method from the boot
method of a service provider. You may do this from the existing AppServiceProvider
or create an entirely new provider:
Once the session driver has been registered, you may use the mongo
driver in your config/session.php
configuration file.
A session key is a single-use symmetric key used for encrypting all messages in one communication session. A closely related term is content encryption key (CEK), traffic encryption key (TEK), or multicast key which refers to any key used for encrypting messages, contrary to other uses like encrypting other keys (key encryption key (KEK) or key wrapping key).
Session keys can introduce complications into a system, yet they solve some real problems. There are two primary reasons to use session keys:
- Several cryptanalytic attacks become easier the more material encrypted with a specific key is available. By limiting the amount of data processed using a particular key, those attacks are rendered harder to perform.
- asymmetric encryption is too slow for many purposes, and all secret key algorithms require that the key is securely distributed. By using an asymmetric algorithm to encrypt the secret key for another, faster, symmetric algorithm, it's possible to improve overall performance considerably. This is the process used by PGP and GPG.[1]
Like all cryptographic keys, session keys must be chosen so that they cannot be predicted by an attacker, usually requiring them to be chosen randomly. Failure to choose session keys (or any key) properly is a major (and too common in actual practice) design flaw in any crypto system.[citation needed]
See also[edit]
References[edit]
Php Session In Database
- ^OpenPGP Message Format http://tools.ietf.org/html/rfc4880