Last time, we looked at how passwords work. To confirm your identity, companies salt your password, they hash the salted password, and they check your hash. (For brevity, I won’t mention salts anymore. Assume that salts are used.)
We left out 3 important questions.
1. Can a hacker find out our passwords from hashes?
Yes and no. We will see that a hash function that is designed well acts like a trapdoor. We can change passwords to hashes, but there is no way to change hashes back to passwords. However, the hacker can still make guesses at our passwords and check which ones result in the stolen hashes. We call this an attack. I will cover 2 ways to make an attack.
2. Can the hash function stop attacks?
Yes, a hash function that is designed well makes attacks difficult. I will explain what I mean by a good design.
3. What can we do to protect ourselves?
We can’t completely rely on the hash function to protect us. We have to be vigilant, too. I will show you how to create good passwords and keep your accounts safe.
Continue reading “p@55w0rd$: Part 2”
There are many things we need to function every day: love, family and friends, good health, puppies, Toastmasters. There is one more: passwords. Think about it. We use passwords every day, when we check our computer, phone, email, Facebook, Twitter, bank account—basically, anything that represents us. Passwords are valuable.
Continue reading “p@55w0rd$: Part 1”
You may have seen braille in elevators and on ATMs and door signs, but brushed it off as something that’s for blind people and not for you. As a student, you may have seen braille in a math problem involving patterns and binary choices. As a puzzle enthusiast, you may have seen braille in a decryption challenge. But is that all there is to braille?
For an upcoming Toastmasters speech, I decided to get to know braille, by researching and interviewing locals who professionally work with people who are blind and visually impaired. Surprisingly, the more I looked into braille, the more I realized its diminishing role in the modern world. I want to address the problem today.
Continue reading “Braille in Modern World”
Last time, we considered the linear equations and linear inequalities that the solution of a nonogram must satisfy. Let us now solve the minimization problem and see how well compressive sensing works. I will consider several examples, then offer a simple fix for the problems that we will encounter.
Continue reading “Solving Nonograms with Compressive Sensing: Part 4”