Archive for September 9, 2015

Wednesday, September 9, 2015

Microsoft Excel Tips

Former Excel developer Joel Spolsky demonstrates some basic ways to use Excel more effectively (tweet, Trello notes). I don’t usually like watching videos, but this one is fast-paced and had some tips that were new to me. The more you learn about Excel, the harder it is to like Numbers and Google Sheets, although the latter is unbelievably convenient for collaborating.

Via the Twitter replies, I also found a mind-bending talk by Felienne Hermans called “Spreadsheets for Developers.”

Previously: Microsoft Excel 2011 for Mac Keyboard Shortcuts.

Update (2015-09-13): Marcel Weiher:

Intuitively, restricting the variables to take only integer values should be easier/quicker, but the reverse is true, and in a big way: once you have integer programming or mixed-integer programming, everything becomes NP-hard.

In fact, I just saw this in action during Joe Spolsky’s talk “You suck at Excel”: he turned on goal-seeking (essentially a solver), and it diverged dramatically. The problem is that he was rounding the results. Once he turned rounding off, the solver converged to a solution fairly quickly.

Apple Tangles With U.S. Over iMessage Data Access

Matt Apuzzo, et al. (via Christopher Soghoian):

With Apple, the encryption and decryption are done by the phones at either end of the conversation; Apple does not keep copies of the message unless one of the users loads it into iCloud, where it is not encrypted. (In the drug and gun investigation this summer, Apple eventually turned over some stored iCloud messages. While they were not the real-time texts the government most wanted, officials said they saw it as a sign of cooperation.)

What they mean here is that iCloud backups, which are enabled by default, are not encrypted. So, as I’ve said, it’s pretty much irrelevant that the iMessage communications themselves are encrypted end-to-end. Unlike with USB syncing, there is no way to make an encrypted cloud backup of an iPhone. Nor is there a way to do a cloud backup that excludes iMessage data.

Matthew Green:

It’s a vague headline that manages to obscure the real thrust of the story, which is that according to reporters at the Times, Apple has not been forced to backdoor their popular encrypted iMessage system. This flies in the face of some rumors to the contrary.


While it seems pretty obvious that Apple could in theory substitute keys and thus enable eavesdropping, in practice it may require substantial changes to Apple’s code. And while there are a few well-known cases in which the government has forced companies to turn over keys, changing the operation of a working system is a whole different ball of wax.

Ben R.

Apple controls iPhones. They have root access, you don’t. It’s the future that Richard Stallman predicted in The Right To Read, except he thought it would be Microsoft. In this kind of situation, why would you even mention key substitution attacks? It’s like speculating about the owners of an Internet café implementing a TLS MITM attack in their own network’s router in order to spy on HTTPS connections originating from their own machines. Why bother when you’re root?

Update (2015-09-12): Bruce Schneier:

The rumor I am hearing is not about access to a particular user and his communications. It is about general access to iOS data and communications. And it’s in the FISA court, which means that it’s not a domestic criminal matter.

Wikipedia Editors Uncover Extortion Scam

Lauren C. Williams (via Mark Bernstein):

The Wikimedia Foundation, the non-profit organization that sponsors but does not operate Wikipedia, announced Monday that at least 381 accounts have been suspended for “black hat” editing, in which editors charge and accept money for “to promote external interests.”


What makes Orangemoody different are its guerrilla recruiting efforts and the group preying on new or gullible Wikipedia users. “This syndicate went out and looked at articles that were being deleted and went and contacted people who were new and wanted an article but were rejected,” Lih said. “WikiPR was not recruiting people to our knowledge; people would approach them.”

Moreover, Orangemoody editors created false threats and, from separate accounts, members would threaten to delete an article and, through another account, tell clients they can ensure the page won’t get deleted for a $30 monthly fee even though most of the pages didn’t meet Wikipedia’s notability standard, which require the article subject to have extensive media coverage — that excludes company websites or press releases, or passing mentions, such as in a listicle.

Thunderbolt Ethernet Adapter Says Cable Unplugged (When Not)

stevenforster1 suggests:

I was having this problem and even after following the above steps.  I then used the Help Center and found how to create a new “Bridge Virtual Network Interfaces” instruction.

  1. Choose Apple menu > System Preferences, then click Network.
  2. Choose Manage Virtual Interfaces from the Action menu.
  3. Click Add (+), choose New Bridge, then select the interfaces to include in the bridge.

I deleted the profiles already there, added the Thunderbolt back in, hit apply and good to go now.

This worked for me.