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Articles related to "hackernews"


Cracking LUKS/dm-crypt passphrases

  • There are already ready-made tools, but we have also produced and published our own in order to support newer LUKS format/ciphers/hashing.
  • When you setup the passphrase for the encryption, you are actually changing the passphrase for the slot and you’re not changing the master key itself as that would require reencrypting the whole partition.
  • Both Hashcat and John the Ripper support password cracking of LUKS passphrases, but they are both limited to what cipher/hashing/LUKS[12] they support.
  • If you’re lucky enough that you need to recover passphrase from some older LUKS encryption, you can use both tools.
  • Currently, to crack newer or other uncommon formats, it is only possible to use cryptsetup based tools.
  • The only issue with bruteforce-luks is that you cannot use John the Ripper and hashcat powerful candidate rule generation as it does not support stdin.

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Open-sourcing F14 for memory-efficient hash tables

  • Much of the variation between hash table algorithms comes from how they handle collisions (multiple keys that map to the same array index).
  • Algorithms generally use either chaining, which uses a secondary data structure such as a linked list to store all the keys for a slot, or probing, which stores keys directly in the main array and then keeps checking new slots if there is a collision.
  • The two-step search is a bit more work than in a normal hash table algorithm when neither has a collision, but F14 is faster overall because there’s a much lower probability that a collision will interfere with instruction pipelining.
  • Despite having a smaller maximum load factor, a probing table that uses sentinels ends up using less overall memory because its data space waste is smaller than the metadata waste of std::unordered_set.

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Coping with Flexbox

  • If only someone paid me everytime I visited CSSTrick’s flexbox guide…or at least all those times when I fiddled around {justify,align}-{content,items} trying to make something happen on screen.
  • With that intro, here’s the start: There are only two properties you’ll need to know to use flexbox are align-items and justify-content.
  • These two cover many usecases one might have: aligning each item on an imaginary line in various ways and varying spacing.
  • justify-content aligns each of the items along a horizontal axis1.
  • By default a flex container’s content doesn’t wrap, but can be controlled using the flex-wrap: 1 property.
  • With wrapped content, there’s one more property we’ll have to know: align-content.
  • This property controls the alignment of the wrapped lines along a vertical axis.
  • To summarize, align-* properties work on the vertical axis, and justify-* properties work on the horizontal axis.

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Four compulsive advantages of Industry 4.0

  • Such waves created by technology are never-ending and right now, we are at the next transitional phase, which has been brewing for quite some time and is all set to lead to a new high in the industries.
  • While some claim that Industry 4.0 is a mere marketing gimmick, one cannot help but notice the huge impact it is already creating in various forms like AI, Internet of Things, Cloud technology, big data and analytics, cybersecurity, augmented reality, etc.
  • Elevating the business model with aspects like digital transformation, automation, large data collection, and many more specific ones naturally have several advantages.
  • With all businesses, big and small, working on similar developments and having similar investments, large corporations also collaborate more with smaller firms to help them move faster in the direction of industry 4.0, thus making the competition almost equal or keeping them on a level playing field with corporate giants.

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What I Learned about Style and Writing from Watching Bruce Lee

  • Like Spiderman, I have great power and great responsibility, and martial arts teaches how to develop both.
  • When kicking, the most important factors are, in order, accuracy then speed then power.
  • Power is least important because any somewhat practiced martial artist will be able to deliver harder strikes than they can withstand by a wide margin.
  • Similarly, when writing, accuracy then speed then power are important.
  • He took a holistic approach to martial arts and pioneered advances in training methods, demonstration techniques, and blending styles.
  • Individual and school style can translate across disciplines, for example, my boxing style is very long-range and footwork based thanks to TaeKwonDo. Lee cut this knot by describing the “style of no style.” His martial arts combined multiple influences into “Jeet Kune Do” or “The Way of the Intercepting Fist,” though his later statements on style resisted even his own definition.

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A function to sleep a 1000 years: explained

  • I encountered a code challenge that asked for a sleep function that sleeps a 1000 years.
  • The current functions use an integer to declare the amount of seconds, but 232 is only around a 100 years long.
  • After issuing the diagnostic, an implementation may choose to assume an implicit int and continue to translate the program in order to support existing source code that exploits this feature.
  • This function takes no parameters and gets the default return type.
  • So, now we have an int called i and a function with return type int called f().
  • According to the author, it stops at approximately a thousand years.
  • 0 would mean that f(sleep(7)) would not be run, and that’s the end of our f().
  • Let’s calculate the amount of years that this will run.
  • So this code will indeed run for a thousand years, with a margin of ten percent.

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Why we fall for cons

  • Like any man in uniform, Captain Voigt appeared taller and broader thanks to his boots, smart grey overcoat and Prussian-blue officer’s cap.
  • As the small group marched towards Putlitzstrasse station, the charismatic Captain Voigt saw another squad and ordered them to fall in behind.
  • Captain Voigt’s impromptu strike force burst into Köpenick town hall and into the office of the mayor, a man named Georg Langerhans.
  • Since Wilhelm Voigt persuaded people to obey orders that they should not have obeyed, you may already be thinking about Stanley Milgram.
  • On showing up at the laboratory, in a basement at Yale University, they met a man — apparently a scientist, just as Voigt had apparently been a Prussian army captain — dressed in a tie and grey lab coat.
  • Voigt stopped Corporal Muller in the street and demanded to know where he and his men were going.

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Clever crows have learnt how to make a meal of cane toads

  • MEMBERS OF THE crow family, the corvids, show a capacity to learn and solve problems that may be unrivalled in the bird world.
  • As this highly poisonous amphibian disperses across northern Australia, the numbers of predators attempting to eat them are crashing.
  • Crows, however, have learnt how to eat toads by avoiding the most toxic parts.
  • The large parotid glands on the toad’s neck and shoulders are the greatest risk.
  • When a toad is harassed, milky white poison oozes from these glands.
  • Crows avoid contact with the ooze by grasping them by the limbs or even the bony brow above the eye, avoiding the body itself.
  • Crows know which bits to eat – fleshy thighs, tongues, intestines – and how to get at these from below without contacting the lethal parts.
  • Certainly corvids naturally occur with toads on all continents outside Australia.

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Proprioception: The Silent “Sixth” Sense

  • Sana is one of the few people in the entire world who knows what it’s like when the proprioceptive sense is turned off.
  • “Even with my eyes open, when I touch the little ball, I don’t feel it,” Sawsen says.
  • Sana, Sawsen, and a handful of similar patients are ideal subjects for scientists who study touch and proprioception.
  • “If you want to move in a coordinated fashion, you have to know where your body is at all moments,” says Adam Hantman, a neuroscientist at the Howard Hughes Medical Institute who studies proprioception.
  • Piezo2, further research revealed, is a molecule critical for both touch and proprioception, a gateway through which mechanical forces begin their journey into our consciousness.
  • Sana and Sawsen, like Bönnemann’s first patient, were born with a genetic mutation that makes their piezo2 genes non-functioning.
  • Without piezo2, the sisters can’t feel light, gentle touch, particularly on their hands and fingers.

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Centaur Unveils Its New Server-Class x86 Core: CNS; Adds AVX-512

  • Since then, the small Austin team refocused its efforts and has been diligently working on its next project – a high-performance data center and edge x86 chip with powerful integrated AI acceleration.
  • Before we dive into the core microarchitecture, it’s important to look at the full SoC Centaur developed, codename CHA.
  • At the heart of the new CHA SoC are eight new high-performance x86 cores, codename CNS.
  • As usual, you can find a fully complete microarchitectural deep dive of the new core on our main CNS WikiChip article.
  • Turns out Centaur didn’t add one with this design – a crucial component found in all Intel big cores for the past decade and something AMD has added with its recent Zen-based microarchitecture series.
  • Most recently, Intel’s own small-core team introduced an entirely radical approach to this problem with multiple out-of-order decode clusters.

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