A hashing algorithm is a fast, one-way function that lets you take a piece of data and convert it to something else (called the hash). Thus, you can compare hashes of two strings to make sure that the original strings are the same. A hash collision occurs when two strings have the same hash, and a collision attack is one where given a hash, you try to come up with a string that has the same hash (thereby violating the one way property of the hashing algorithm)

SHA-1 is a hashing algorithm from early 90s that, over the past decade or so, is no longer considered secure against well-funded opponents.

Today, CWI Amsterdam and Google announced a practical collision attack against SHA-1, publishing two dissimilar PDF files which produce the same SHA-1 hash as proof of concept.

Hi everyone! I'm Andy and I'm an investor at Social Capital based in Palo Alto, CA. Social Capital is a partnership of philanthropists, technologists and capitalists utilizing venture capital as a force to create value and change on a global scale.

Previously, I ran finance and built out the analytics for OMGPOP, a VC backed social gaming startup. We sold the company to Zynga in March 2012 for $180M.

Before OMGPOP, I began my career with IBM's M&A team buying software companies ranging from $20M - $10B+ valuations. I'm passionate about startups, especially ones focused on health and data.

Ask me anything!

Moderator note: We are very excited to have Andy do this Q&A Session for us here! You can follow Andy on Twitter (@artzandy) and ask him about Mergers & Acquisitions, Financial Modeling, Due Diligence, Financial Management, Budgeting, Venture Fundraising, Data Mining, mySQL and Web Analytics.

A huge contributor to Apple's high retention amongst iPhone users is attributable to iOS — for most of the world it is unimaginable for an iPhone user to upgrade to anything but another iPhone: there is too much of the user experience, too many of the apps, and, in some countries like the U.S., too many contacts on iMessage to even countenance another phone.

Unlike the rest of the world, in China the most important layer of the smartphone stack is not the phone’s operating system. Rather, it is WeChat, making iOS irrelevant for the Chinese. WeChat is your phone — and it works the same on iOS or Android.

Read the full article for a deeper analysis around this interesting observation.

Mark Zuckerberg, Facebook’s chief executive, has cultivated relationships with China’s leaders, including President Xi Jinping. He has paid multiple visits to the country to meet its top internet executives. He has made an effort to learn Mandarin.

Inside Facebook, the work to enter China runs far deeper. The social network has quietly developed software to suppress posts from appearing in people’s news feeds in specific geographic areas, according to three current and former Facebook employees, who asked for anonymity because the tool is confidential. The feature was created to help Facebook get into China, a market where the social network has been blocked, these people said. Mr. Zuckerberg has supported and defended the effort, the people added.

It's been almost impossible for US Tech companies to...

Documentary by Wired

A very interesting article by Ben Thompson on how, if you can in some sense define operating systems as the chokehold between hardware manufacturers and the software that runs on top - you can think of Alexa as Amazon's operating system for the home. I really like how the article gradually builds on history to chronicle a path of how we got here.