# entropy

Published articles for entropy.

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## A Proofless Introduction to Information Theory

DevFeed: [A Proofless Introduction to Information Theory](<https://devfeed.tech/articles/a-proofless-introduction-to-information-theory-40377.md>)

Original publisher: [Read original article](<https://www.jeremykun.com/2015/02/16/a-proofless-introduction-to-information-theory/>)

Published: 2015-02-16T09:00:00Z

Content type: tutorial

Language: en

Sources: [Jeremy Kun](<https://devfeed.tech/sources/jeremy-kun.md>)

Topics: [Encoding](<https://devfeed.tech/topics/encoding.md>), [digital](<https://devfeed.tech/topics/digital.md>)

Tags: [channel](<https://devfeed.tech/tags/channel.md>), [coding-theory](<https://devfeed.tech/tags/coding-theory.md>), [communication](<https://devfeed.tech/tags/communication.md>), [compression](<https://devfeed.tech/tags/compression.md>), [digital](<https://devfeed.tech/tags/digital.md>), [encoding](<https://devfeed.tech/tags/encoding.md>), [entropy](<https://devfeed.tech/tags/entropy.md>), [error](<https://devfeed.tech/tags/error.md>), [error-correction](<https://devfeed.tech/tags/error-correction.md>), [example](<https://devfeed.tech/tags/example.md>), [explain](<https://devfeed.tech/tags/explain.md>), [hamming](<https://devfeed.tech/tags/hamming.md>), [independent](<https://devfeed.tech/tags/independent.md>), [information](<https://devfeed.tech/tags/information.md>), [information-theory](<https://devfeed.tech/tags/information-theory.md>), [kolmogorov-complexity](<https://devfeed.tech/tags/kolmogorov-complexity.md>), [language](<https://devfeed.tech/tags/language.md>), [markov](<https://devfeed.tech/tags/markov.md>), [mathematics](<https://devfeed.tech/tags/mathematics.md>), [messages](<https://devfeed.tech/tags/messages.md>), [models](<https://devfeed.tech/tags/models.md>), [probabilistic-method](<https://devfeed.tech/tags/probabilistic-method.md>), [problems](<https://devfeed.tech/tags/problems.md>), [shannon](<https://devfeed.tech/tags/shannon.md>), [theory](<https://devfeed.tech/tags/theory.md>)

### AI overview

A proofless introduction to information theory explains noiseless and noisy communication problems, encoding schemes, entropy, and how entropy differs from Kolmogorov complexity.

### Source excerpt

There are two basic problems in information theory that are very easy to explain. Two people, Alice and Bob, want to communicate over a digital channel over some long period of time, and they know the probability that certain messages will be sent ahead of time. For example, English language sentences are more likely than gibberish, and "Hi" is much more likely than "asphyxiation." The problems are: Say communication is very expensive.

## Hardware entropy: RDRAND

DevFeed: [Hardware entropy: RDRAND](<https://devfeed.tech/articles/hardware-entropy-rdrand-38923.md>)

Original publisher: [Read original article](<https://idea.popcount.org/2013-03-25-hardware-entropy-rdrand>)

Author: Marek

Published: 2013-03-24T23:00:00Z

Content type: article

Language: en

Sources: [Marek Majkowski](<https://devfeed.tech/sources/marek-majkowski.md>)

Topics: [Randomizer](<https://devfeed.tech/topics/randomizer.md>), [Hardware](<https://devfeed.tech/topics/hardware.md>), [cpu](<https://devfeed.tech/topics/cpu.md>), [Security](<https://devfeed.tech/topics/security.md>), [intel](<https://devfeed.tech/topics/intel.md>), [Linux Kernel](<https://devfeed.tech/topics/linux-kernel.md>)

Tags: [aes](<https://devfeed.tech/tags/aes.md>), [ansi](<https://devfeed.tech/tags/ansi.md>), [bits](<https://devfeed.tech/tags/bits.md>), [cryptographic](<https://devfeed.tech/tags/cryptographic.md>), [entropy](<https://devfeed.tech/tags/entropy.md>), [fips](<https://devfeed.tech/tags/fips.md>), [generator](<https://devfeed.tech/tags/generator.md>), [hardware](<https://devfeed.tech/tags/hardware.md>), [intel](<https://devfeed.tech/tags/intel.md>), [kernel](<https://devfeed.tech/tags/kernel.md>), [linux-kernel](<https://devfeed.tech/tags/linux-kernel.md>), [nist](<https://devfeed.tech/tags/nist.md>), [security](<https://devfeed.tech/tags/security.md>), [time](<https://devfeed.tech/tags/time.md>)

### AI overview

This article explains Intel's RDRAND instruction, which uses an on-processor entropy source and AES conditioning to produce hardware-generated random numbers. It also describes checking the carry flag because RDRAND may temporarily return no data when demand exceeds hardware supply.

### Source excerpt

Hardware entropy: RDRAND This is the third blog post on machine instructions: This time I've noticed instruction. According to Wikipedia is: ... a random number generator that is compliant with security and cryptographic standards such as NIST SP800-90, FIPS 140-2, and ANSI X9.82. The generator uses an on-processor entropy source, which passes the randomly generated bits to an AES (in CBC-MAC mode) conditioner to distill the entropy into non-deterministic random numbers. Sounds good.