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EMV: A Multitude of Payment Solutions

Clearent Payments API

What is EMV?  EMV, by definition, “is a global standard for credit and debit payment cards based on chip card technology taking its name from the card brands Europay, MasterCard, and Visa – the original card brands that developed it.” That definition doesn’t tell us much. Most of us understand EMV to mean chip cards that can be inserted into a slot in the payment terminal. Chip cards allow additional verification to prevent fraud in card-present transactions. They are much harder to copy than the traditional magstripe.  They also have additional verification built into each transaction so that each use can’t be reused, like magstripes can be.

EMV has disrupted the industry because as of October 2016 the Card Brands (MasterCard, Visa, Discover and Amex) have required their merchants to either accept EMV chip cards, or be responsible for additional fraud liability. This has been referred to as the liability shift. This liability shift has rattled the payments industry. It’s the first time in years that U.S. merchants will be forced to upgrade their point-of-sale (POS) equipment and terminals. Vendors of terminals are scrambling to support the technology and grab more market share; merchants that are forced to buy new equipment start looking at new vendors. Read more

Using Feature Switches for Code

Code

Using feature switches fore code development is a technique used by software developers or DevOps professionals to turn portions of code on or off without requiring a rebuild of the application.  There can be many reasons for using this technique. Often, a feature may need to be released but is in the same build as a feature that cannot be released.  In other cases important code releases require customer notification that may not have happened yet.  Releasing the code with the ability to turn certain features off can clear it as a work item for the IT team while leaving the business with the flexibility to release the feature at a later date.

Feature switches for the Clearent back end development team typically come in two parts: a configuration setting indicating the state of the feature and a dependency swap or IF statement to switch the behavior out based on the configuration setting.  Here is a simple example of what a feature switch could look like:

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OWASP Security Vulnerability #9 – Components with Vulnerabilities

Developer Cyber Security PCI

This post is a continuation from my first Developer Blog post “PCI Check Up” – outlining the OWASP Top 10 web security vulnerabilities.  We keep these security vulnerabilities in mind as we build out our own payments platform and provide integration points to our partner developers.  In this post, I will review the number 9 OWASP web security vulnerability.

The number 9 vulnerability is Using Components with Known Vulnerabilities.  Most modern web applications take advantage of third-party libraries or frameworks that facilitate application development.  If those third-party components have vulnerabilities in them, then by extension any application that uses those components have security vulnerabilities.  It seems fairly obvious, but many developers simply lose site of this concern.

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Why We Use TDD

Love Test Drive Development

Ever since I started working as a developer for Clearent, I’ve been an adamant supporter of Test Driven Development (TDD).  I adopted this development practice a very long time ago and have seen its benefits over and over again.

What is TDD?

Test Driven Development is a coding practice where a developer writes a failing unit test before writing the production code to make the test pass.  Ideally, the unit test is built up slowly, adding a failing test condition that drives the next incremental feature in the code being created.  (We achieve this incremental build-up by practicing a coding pattern called red-green-refactor.)  The design of the code is “discovered” as the test is built-out, and the end product is a well-designed piece of functioning code.  A by-product of this practice is a unit test that can be repeatedly run to ensure future changes don’t break the existing code base.
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PCI Check Up

Clearent PCI

At Clearent, we are starting preparations for our annual PCI audit.  One of the components of the PCI audit is ensuring that web applications guard against the OWASP Top 10 Web Application Vulnerabilities.  I thought this would be a good time to review that list.

The OWASP.org_PDF is the best source of information if you are creating web applications.  Below is a listing of the 10 vulnerabilities and a brief explanation of them.

Top Ten Web Application Vulnerabilities:

  1. Injection: This vulnerability covers all kinds of injection attacks, including SQL injection.  Applications need to ensure that user-entered data can’t modify execution paths of the application itself.  It is important to guard against data coming into the application, as well as data being retrieved by the application.
  2. Broken Authentication and Session Management: Quite often developers create all of their application’s functionality themselves, and introduce bugs.  Authentication and Session management are no different.  If possible, use tried-and-true third party applications to handle these functions.
  3. Cross-Site Scripting (XSS): XSS is a nasty vulnerability that typically hijacks a user’s browser to access a malicious website or to steal data.  Applications generally protect against this flaw by properly escaping data entered through the browser.
  4. Insecure Direct Object References: This vulnerability typically happens when a developer exposes file names, unique identifiers or other “internal” data that would allow an attacker to directly manipulate the system, bypassing data validation checks.
  5. Security Misconfiguration: Not locking down systems, changing default passwords, or keeping software up-to-date causes this vulnerability.  All of these things seem obvious, but if they are obvious to us, they are obvious to attackers as well.
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My first eCommerce Meetup

eCommerce

I was so excited that I recently received a notification from Meetup.com informing me that an eCommerce meetup had been organized here in St Louis!

It didn’t surprise me that there wasn’t an eCommerce group overview or agenda, because I thought the person who registered the meetup might have been new to the process. It was listed as a technical meetup, so I was excited to see what I could do to help establish the eCommerce groups goals, help formulate future agendas and help line up future sponsors. Initially, only three people had signed up for the eCommerce meetup, as it was a fairly narrow interest, but I had grand hopes of building up the membership.

I thought it was a little unusual that the meeting was going to be held in a higher end neighborhood at the local Hilton, which sounded cool since most of the meetup’s I attend are low budget. So I figured whoever started this meetup had some sponsorship already and was going high-end. Cool, high-end meetup!

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Switching to Distributed Version Control

Distributed Version Control

One of the best parts of being a developer at Clearent is being part of a culture of constant improvement and growth. This culture allows us to consistently improve our payments platform and the products we as developers create for other developers to accept payments. We are not a company that refuses to change simply because “that’s the way we’ve always done it”. Every day is an opportunity to try something new, whether it’s a new framework, a new platform, or a new toolkit. All of this, in the name of creating the best possible payments platform.

A couple years ago, we decided to make the transition from a centralized version control system (subversion) to a distributed version control system (git).  And in that transition was a real opportunity to change the way we use source control.

We started with three assumptions:

  1. Branches are Cheap
  2. Merges are Easy
  3. Conflicts are Rare

If you have only used centralized version control systems (VCS), those first two assumptions sound crazy.  Most of the popular centralized VCSs are either incredibly slow to branch or make it very difficult to manage to multiple branches. We had actually built our own internal tool to help us manage merging our long-lived development branch into our testing and release branches. Version control systems are supposed to be a tool that helps developers do their jobs, but for us it almost more of an obstacle.

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Integrating Payments into a Spring Boot Service

RESTful Interface Flow

This is a quick tutorial showing how easy it is to integrate with Clearent’s secure payments gateway. Clearent has designed a language agnostic RESTful online payments gateway, meaning developers of almost any language should be able to start processing with Clearent.

Today we’ll be using Spring Boot and a handful of other libraries to get a payments service up and running fast. Spring Boot provides an opinionated implementation of the Spring framework in an embedded JAR file. We’ve been using it internally here at Clearent for over a year now, and has reduced our development time and has provided quick integration with thousands of popular libraries and tools. We’re going to assume some basic familiarity with Spring Boot, but if you’d like an introduction, Spring’s Tutorial on Building REST Services demonstrates all of the topics covered in this post.

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Succeeding with Failure for Developers

Clearent Developers Failure to Succeed

Developers hope (and pray) that when facing system application failure it does so in a predictable and recognizable way.  Nobody wants to get the 3 a.m. phone call from a sysadmin saying that a core process failed and reported an “unknown error.”  As Clearent has grown we have learned a few things about failure.  We’ve also had to rethink what failure means and how we adapt to the unexpected.  We are continually learning, so I can’t provide a definitive guide on how to write fault-tolerant systems but here are a few things we’ve learned along the way.

Logging

Have a top-level exception handler that logs any error that causes your application to fail.  Hopefully it is never exercised but nobody wants an application that fails and doesn’t say why.  This can get tricky as processes spawn threads, so be aware that it may not always be near the entry point of your application.

Take advantage of logging levels to throttle the amount of data you emit.  Most logging frameworks have the ability to write out messages at levels such as Debug, Info, Warn, Error, or Fatal.  When the going gets tough in production your operations staff can make the logging more verbose to gain insights into what the application is doing.  When everything is operating normally it can be turned back down again without requiring development time to add and remove logging.
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Working Toward Continuous Delivery

continuous delivery

One of the biggest difficulties in software development is deployment.  Figuring out how to package an application, transfer it around, install it, etc. has been a challenge from the dawn of programming.  Continuous delivery is a term used to describe an environment where software flows from a developer into production, through all of the necessary gates, with minimal manual work.  Clearent has always worked to simplify the software deployment process so that we can deliver new features to our customers quickly and efficiently with minimal disruption.  As the underlying technology stack evolves, we are able to move toward a true automated continuous delivery system.

 

Software is typically difficult to release.  The process flow is generally:

  1. A developer creates or makes changes to a piece of software and tests it on a local system.
  2. The software is moved to an integration system to ensure it works with the rest of the software available.
  3. The software is moved into an environment where quality assurance testing can be performed.
  4. The tested software is moved into the production environment.

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