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Paragon Initiative:
Choosing the Right Cryptography Library for your PHP Project: A Guide
Nov 16, 2015 @ 12:19:16

On the Paragon Initiative blog there's a new article posted that wants to help you pick the right cryptography library for your project and your needs. In it they make several recommendations and the benefits of each.

Cryptography is not magic. Adding encryption to an application doesn't automatically make it secure against attackers (especially if you aren't authenticating your ciphertext). But if you do need it to satisfy a business need, conventional wisdom states that you almost certainly should not try to design your own cryptography. Instead, you should use an existing cryptography library.

Okay, great. So which PHP cryptography library should I use? That depends on your exact requirements. Let's look at some good choices. (We won't cover any terrible choices.)

The three libraries they recommend are: Halite, the Libsodium library, the Defuse Security PHP Encryption library and the PHPSecLib library. For each they make some recommendations on places they may be most effective and how it using them relates to passwords (hint, hashing over encryption).

tagged: cryptography library choice hailite libsodium phpencryption phpseclib password

Link: https://paragonie.com/blog/2015/11/choosing-right-cryptography-library-for-your-php-project-guide

Paragon Initiative:
Coming to WordPress 4.4: CSPRNG
Oct 12, 2015 @ 12:52:42

The Paragon Initiative blog has a post from Scott Arciszewski about a new feature coming to upcoming WordPress versions - the use of a cryptographically security random number generator starting in version 4.4.0.

At Paragon Initiative Enterprises, we believe that security should be the default state of affairs, not something only in the reach of security experts. That is why [...] our team spends a great deal of time working to improve the security of popular free and open source software.

Today, we're pleased to announce an exciting security enhancement coming to WordPress in the next major version. Starting in 4.4.0, wp_rand() is cryptographically secure on all platforms.

He walks the reader through the "road" that's lead to the introduction of this support and the work he did in the past to help push the project (and others) towards it. Given that the WordPress project has a lot of emphasis on backwards compatibility, effort need to be put into a method that would work across new and old PHP versions. The random_compat library was created and was adopted not only by WordPress but also by several other major PHP projects.

Our part in this long and crazy journey has reached its end. In the course of fixing the same flaw in two distinct projects, the PHP community banded together to identify and expunge a bug in the PHP core, create a new feature in PHP 7, and in some small way helped to secure the CMS that powers more than 20% of websites on the Internet.
tagged: wordpress csprng random number generator cryptography security

Link: https://paragonie.com/blog/2015/10/coming-wordpress-4-4-csprng

Paragon Initiative:
How to Safely Implement Cryptography Features in Any Application
Oct 07, 2015 @ 11:51:41

The Paragon Initiative blog has posted a new article showing you how to safely implement cryptography in any PHP-based application (or really just about any application) with the help of libsodium.

Why not {Mcrypt, OpenSSL, Bouncy Castle, KeyCzar, etc.}? These cryptography libraries are really building blocks that by and large must be used, with expert care, to build the interfaces you want developers to use. In most cases, libsodium is the interface you want developers to use. [...] By default, these libraries don't provide [authenticated encryption](https://tonyarcieri.com/all-the-crypto-code-youve-ever-written-is-probably-broken). Most of them force developers to use RSA (or ECDSA but certainly not EdDSA), which is [hard to get right](http://www.daemonology.net/blog/2009-06-11-cryptographic-right-answers.html) and for which [index calculus attacks are improving each year](https://events.ccc.de/congress/2014/Fahrplan/system/attachments/2501/original/20141227.pdf).

He goes on to talk about NaCI as a possible option (libsodium is from a fork of it) but points out that NaCI isn't as easily available as libsodium to non-C/Python developers. He shares a few reasons why he thinks "libsodium is so great" and a few reasons not to use it (mostly dealing with outside limitations, not technical ones). Finally he points you in the right direction to help you get started using libsodium for PHP as a PECL extension.

tagged: cryptography feature safe guide tutorial introduction pecl extension

Link: https://paragonie.com/blog/2015/09/how-to-safely-implement-cryptography-in-any-application

Paragon Initiative:
You Wouldn't Base64 a Password - Cryptography Decoded
Aug 10, 2015 @ 12:33:43

The Paragon Initiative has posted an article about cryptography, introducing some of the basic concepts and explaining why "you wouldn't base64 a password" to adequately protect it in your application.

If you feel that cryptography is a weird, complicated, and slightly intimidating subject for which your feelings might be best described as lukewarm (on a good day), we hope that by the time you finish reading this page, you will have a clear understanding of the terms and concepts people use when this topic comes up.

He starts with some of the basics around hashing (keyless cryptography) and the advantages/disadvantages of the method. He moves from there a step up and gets into secret key cryptography, using things like HMAC hashing to ensure message validity. The next move up is to secret key encryption, using some kind of "secret" as a part of the encryption process along with the right algorithm and mode for the encryption level desired. He also covers authenticated key encryption, public key encryption, shared secrets and digital signatures. He ends the post covering some of the common pitfalls of using cryptography in things like password storage, file verification and a reminder that encoding (like base64 encoding) and compression aren't encryption.

tagged: encryption introduction cryptography base64 decoded tutorial hashing

Link: https://paragonie.com/blog/2015/08/you-wouldnt-base64-a-password-cryptography-decoded

Paragon Initiative:
Secure Data Encryption in Web Applications with PHP
Aug 03, 2015 @ 10:58:47

The Paragon Initiative has posted a new white paper to their site covering secure data encryption in web applications written in PHP. The paper covers high level topics and offers some more practical suggestions about tools and guides to use in protecting your applications.

Encrypting network communications is absolutely essential to the security of anyone who wishes to use your website or application. The standard and most reliable form of network encryption is called Transport Layer Security (TLS), which was preceded by and older standard called Secure Socket Layer (SSL).

Websites that use SSL or TLS are accessible by typing https://domain.com into your browser instead of just http://domain.com. Consequently, the shorthand way to refer to HTTP over TLS is simply HTTPS. Contrasted with network cryptography, storing sensitive information is a much more challenging and interesting problem to solve, and is the focus of this paper.

Among the topics covered in the white paper are things like:

  • The flow of a HTTPS request (and if it's "fast" or not)
  • Secure password storage and handling
  • On-demand encryption/decryption
  • Cryptography library recommendations
  • Using asymmetric cryptography with public and private keys

They also point to this curated list of resources to help you learn more about general web application security including cryptography.

tagged: secure application cryptography https password library libsodium resources

Link: https://paragonie.com/white-paper/2015-secure-php-data-encryption

PHP Manual Masterpieces:
I Can't Spell PBKDF
Nov 13, 2013 @ 09:58:08

On the PHP Manual Masterpieces site has a recent post looking at PBKDF and PHP (and, more specifically, the information that's presented about it in the manual).

So why are we here? Well, a faithful follower slipped me a tip to check out the documentation. It turned out I agreed: I don’t like it. [...] Let’s be clear: I have read the backing C code of this feature and I see nothing wrong with the actual functionality. My issues are strictly with the documentation and the API, both of which are very PHP-ish in the sorts of ways that drive me to hateblog about a programming language on a Friday night. It turns out there are people who are totally okay with these design decisions, and I can’t help that their subjective tastes are wrong, but that’s just how it is.

She mentions three different major issues with the documentation currently in the manual:

  • Non-copypaste-safe cryptography
  • The fact that PHP does not fail effectively when it comes to cryptographic handling
  • The lack of units defined (like for the "length" parameter of hash_pbkdf2)
tagged: pbkdf cryptography manual examples error failure units

Link: http://phpmanualmasterpieces.tumblr.com/post/66426423275/i-cant-spell-pbkdf

Scott Arciszewski:
Using scrypt in PHP-based Websites
Oct 30, 2013 @ 10:48:18

Scott Arciszewski has posted a new tutorial to his site helping you get scrypt installed as an alternative to some of the other cryptographic functionality that's already supported by PHP (like bcrypt).

Most newbie PHP developers suck at developing user authentication systems. When not storing passwords in plaintext, they just wing it with a simple hash function and hope it's good enough. Instead of md5(), sha1(), or hash(), you should consider using scrypt, pbkdf2, or bcrypt. Today, I'll go through the steps required to start using scrypt in your web applications.

He walks you through the exact steps you'll need to get scrypt installed and working happily with PHP (provided you have root on the machine). Thankfully, it's pretty easy thanks to the scrypt extension provided through PECL. He gives a brief introduction to using the scrypt function and links to an updated version of a scrypt wrapper you can use in your applications.

tagged: scrypt cryptography hashing extension pecl tutorial

Link: https://s.arciszewski.me/blog/2013/10/php-scrypt-setup

Timoh's Pages:
Cryptography in web applications: a false sense of security?
Aug 22, 2012 @ 12:11:11

Timo has a new post looking at cryptography in PHP and some of the common misconceptions and how that functionality that your framework provides might not be good enough.

Does your framework of choice offer an easy way to perform data encryption? Maybe you have even utilized data encryption in some format. [...] It could not be much easier than that. It is hard to argue. But things won’t stay as simple as this if you look at the meaning of “secure data encryption” a little bit closer. Usually people encrypt their data to make sure the data will stay safe. What does this actually mean? Simply put, it means your data stays secret as long as the secret key stays secret. No matter if an active attack is going on and the adversary can read your encrypted data.

He looks at why, by itself, encryption isn't that useful - it's only when its applied. He also covers some of the basic questions to ask when working with things like HMAC hashing and ciphertext malleability. He talks about random number/string generation for IVs, encryption keys and what you can do to help make your encryption more secure in its implementation.

tagged: cryptography security encryption application


Paul Reinheimer's Blog:
Cookies don't replace Sessions
Jan 24, 2012 @ 09:26:20

In a new post to his blog Paul Reinheimer talks about replacing sessions with cookies and some of the (security) pitfalls that can come with it.

I’ve seen several instances where people have demonstrated the ease with which encrypted cookies can replace sessions within PHP. Michael Nitschinger wrote a piece recently demonstrating the switch with Lithium, while CodeIgniter does this by default (optionally encrypting). The problem is that while replacing sessions with cookies works, it introduces a few risks not present with native session support, and these risks tend to be under documented.

He gives an illustration of an attacker who sits between Amazon and one of their warehouses. Despite encrypting their order details, all it would take is the attacker to grab an order and copy it and resend (a "replay attack"). He's created an example application to illustrate the point (source on github). The attacker doesn't even have to know what the encrypted information contains - they only have to replicate it.

tagged: cookies session cryptography advice security replay attack


Suspekt Blog:
mt_srand and not so random numbers
Aug 18, 2008 @ 13:49:31

Stefan Esser points out a problem with the mt_rand and rand methods in PHP that makes them not quite random enough for cryptographic uses.

PHP comes with two random number generators named rand() and mt_rand(). The first is just a wrapper around the libc rand() function and the second one is an implementation of the Mersenne Twister pseudo random number generator. Both of these algorithms are seeded by a single 32 bit dword when they are first used in a process or one of the seeding functions srand() or mt_srand() is called.

He looks at how its currently implemented, some examples of bad methods to get "random" numbers, how shared resources are a problem and an example of a cross-application attack (the application in more than once place using the same method for getting random numbers).

In the comments he recommends either grabbing from /dev/random (if you're on a unix-based system) or making the creation of your numbers a bit more complex to include things the outside world wouldn't know.

tagged: mtrand random number rand cryptography problem