Cryptography Archives – Practical Networking .net

RSA, Diffie-Hellman, DSA: the pillars of asymmetric cryptography

Ed Harmoush — Fri, 03 Dec 2021 18:38:45 +0000

The world of modern cryptography is built upon the concept of Asymmetric Encryption, and the pillars of Asymmetric Encryption are these three algorithms: RSA, Diffie-Hellman, and DSA (Digital Signature Algorithm). But unfortunately, there are many misconceptions about these algorithms, and about Asymmetric Cryptography itself. In this article, we’re going to look at each of these… Read More »RSA, Diffie-Hellman, DSA: the pillars of asymmetric cryptography

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Square and Multiply

Ed Harmoush — Wed, 09 Mar 2016 22:13:41 +0000

We’ve all done math problems that look like this: 35, 410, or N37. These are known as an exponentiation. And there is a trick to solving these problems with less calculations than simply multiplying the base number over and over again. That trick is known as the Square and Multiply method. Take 35. If doing that… Read More »Square and Multiply

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Cryptography

Ed Harmoush — Sat, 07 Nov 2015 05:19:07 +0000

Do you do online banking? Do you work from home? Do you use VPNs to access company resources? All these would not be possible without Cryptography. Cryptography is the art of keeping secrets, specifically through any form of communication. Cryptography has existed for thousands of years, but has become increasingly more important in recent history due… Read More »Cryptography

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Authentication

Ed Harmoush — Fri, 06 Nov 2015 09:48:38 +0000

In Cryptography, the concept of Authentication serves to provide proof that the other side of a communication is indeed who they claim to be, and who you intend for them to be. There are multiple ways to verify the opposing party’s Authentication. We will look at three of the most common: Username and Password Pre-Shared-Key… Read More »Authentication

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Diffie-Hellman Key Exchange

Ed Harmoush — Wed, 04 Nov 2015 08:40:54 +0000

How can two people in a crowded room derive a secret that only the pair know, without revealing the secret to anyone else that might be listening? That is exactly the scenario the Diffie-Hellman Key Exchange exists to solve. The Diffie-Hellman Key Exchange is a means for two parties to jointly establish a shared secret over… Read More »Diffie-Hellman Key Exchange

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Anti-Replay

Ed Harmoush — Tue, 20 Oct 2015 06:04:42 +0000

The Problem Before we can describe the solution, we must first adequately describe the problem Anti-Replay is trying to solve. Imagine your local bank branch office. Imagine someone going to that branch location, and depositing $100 in cash into their account. At some point following the transaction, that branch location will send some packets to the bank headquarters… Read More »Anti-Replay

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Using Asymmetric Keys

Ed Harmoush — Wed, 30 Sep 2015 07:35:34 +0000

We’ve established how Asymmetric encryption makes use of two mathematically linked keys: One referred to as the Public Key, and the other referred to as the Private Key. We’ve also established that what one key encrypts, only the other can decrypt. These two attributes allow us to perform two separate operations with a Key Pair. Asymmetric Encryption Below is… Read More »Using Asymmetric Keys

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RSA Example

Ed Harmoush — Sat, 26 Sep 2015 09:02:34 +0000

The RSA algorithm is the most widely used Asymmetric Encryption algorithm deployed to date. The acronym is derived from the last names of the three mathematicians who created it in 1977: Ron Rivest, Adi Shamir, Leonard Adleman. In order to understand the algorithm, there are a few terms we have to define: Prime – A number… Read More »RSA Example

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Asymmetric Encryption

Ed Harmoush — Fri, 25 Sep 2015 09:20:20 +0000

Earlier, we learned that Symmetric encryption is an encryption scheme that uses the same key to encrypt and decrypt. Conversely, Asymmetric encryption, uses different keys to encrypt and decrypt. Lets take a look at a simple example. For the sake of simplicity, let us pretend for this example that there are only the lower case letters a -… Read More »Asymmetric Encryption

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Hashing Algorithm

Ed Harmoush — Tue, 22 Sep 2015 05:42:27 +0000

The first concept we need to discuss in our exploration of Cryptography is that of a Hashing Algorithm. A Hashing Algorithm is a mathematical formula that takes a Message of arbitrary length as input and produces as output a representational sample of the original data. For instance, a rudimentary example of a hashing algorithm is simply adding… Read More »Hashing Algorithm

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