What are the Cryptographic Hash Functions and for What Purposes?

In this flood, I will talk about Cryptographic Hash Functions such as MD5SHA-1SHA-256 and some usage areas of these functions.

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Cryptographic Hash Functions produce an output with a specific length (eg 20 bytes) regardless of the size of the input they receive. The output produced is specific to the given input. The same output always occurs with the same input, and the output of two different inputs cannot be identical with each other. The output of the Cryptographic Hash Functions can be called “message digest”, “hash”, “checksum” and “digital fingerprint”.

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The Hash function is “broken” as soon as two different inputs “Collision” that make up the same output are found and are not cryptographically strong. For SHA-1, a “Collusion” was detected using 6610 years of processor time in 2017, while MD5 has “Collusion” since 2005. MD5 and SHA-1 Hash functions are not considered strong enough cryptographically today due to the “Collusion” detected.

Now let’s look at the use cases where Cryptographic Hash Functions generate an output that is independent of the input size but has a specific length that defines the input specifically.

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#cryptographic-hash #devops

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Buddha Community

What are the Cryptographic Hash Functions and for What Purposes?
Vincent Lab

Vincent Lab

1605017502

The Difference Between Regular Functions and Arrow Functions in JavaScript

Other then the syntactical differences. The main difference is the way the this keyword behaves? In an arrow function, the this keyword remains the same throughout the life-cycle of the function and is always bound to the value of this in the closest non-arrow parent function. Arrow functions can never be constructor functions so they can never be invoked with the new keyword. And they can never have duplicate named parameters like a regular function not using strict mode.

Here are a few code examples to show you some of the differences
this.name = "Bob";

const person = {
name: “Jon”,

<span style="color: #008000">// Regular function</span>
func1: <span style="color: #0000ff">function</span> () {
    console.log(<span style="color: #0000ff">this</span>);
},

<span style="color: #008000">// Arrow function</span>
func2: () =&gt; {
    console.log(<span style="color: #0000ff">this</span>);
}

}

person.func1(); // Call the Regular function
// Output: {name:“Jon”, func1:[Function: func1], func2:[Function: func2]}

person.func2(); // Call the Arrow function
// Output: {name:“Bob”}

The new keyword with an arrow function
const person = (name) => console.log("Your name is " + name);
const bob = new person("Bob");
// Uncaught TypeError: person is not a constructor

If you want to see a visual presentation on the differences, then you can see the video below:

#arrow functions #javascript #regular functions #arrow functions vs normal functions #difference between functions and arrow functions

What are the Cryptographic Hash Functions and for What Purposes?

In this flood, I will talk about Cryptographic Hash Functions such as MD5SHA-1SHA-256 and some usage areas of these functions.

Image for post

Cryptographic Hash Functions produce an output with a specific length (eg 20 bytes) regardless of the size of the input they receive. The output produced is specific to the given input. The same output always occurs with the same input, and the output of two different inputs cannot be identical with each other. The output of the Cryptographic Hash Functions can be called “message digest”, “hash”, “checksum” and “digital fingerprint”.

Image for post

The Hash function is “broken” as soon as two different inputs “Collision” that make up the same output are found and are not cryptographically strong. For SHA-1, a “Collusion” was detected using 6610 years of processor time in 2017, while MD5 has “Collusion” since 2005. MD5 and SHA-1 Hash functions are not considered strong enough cryptographically today due to the “Collusion” detected.

Now let’s look at the use cases where Cryptographic Hash Functions generate an output that is independent of the input size but has a specific length that defines the input specifically.

Image for post

#cryptographic-hash #devops

Nat  Kutch

Nat Kutch

1596976800

Why Should the Length of Your Hash Table Be a Prime Number?

Every thorough data structures and algorithms course will cover the hash table data structure and, by extension, hash functions. In reviewing data structures recently, I came across the notion of reducing collisions by making the length of your hash table a prime number. Due to the limited scope of the course, the author did not go into much detail as to why this works and encouraged some self-research if so inclined. It turns out I am so inclined and I wanted to get to the bottom of this seemingly magic fix. To provide a little context, we will first briefly go over hash tables, hash functions, what qualities make a good hash function, and finally how a hash table of prime number length reduces collisions.

Hash Tables

With most languages featuring a built-in version of a hash table, they are an extremely useful and common data structure. They are known as dictionaries in Python, objects in JavaScript, Maps in Java, Go, and Scala, and hashes in Ruby. Hash tables are primarily used to store data in key-value pairs. With the ability to quickly locate data using its associated key, hash tables are an excellent option for data access, insertion, and removal. This is a marked improvement over arrays that, while providing quick access using indices, can have costly time complexities when adding and removing elements.

In most cases, utilizing a language’s built-in hash function is probably the best option, however, they can be modeled from scratch using an array. In this case, we would provide the key corresponding to the data we wish to access. This key must be transformed into an index where the key-value pair is stored and then using the index the desired data is returned. This is where hash functions come in to play.

hash functions

In general, hash functions take an input of any size and return an output of a fixed size; it could be a short string or an integer. These functions are ‘one-way’ meaning we cannot construct the original input by working backward from the output. As a result, hash functions are often used in cryptography.

To illustrate, let’s say we are using a has table to store data relating to a collection of books with keys corresponding to the books’ ISBNs and the values of the books’ title. Our hash function would take the ISBN as an argument and return an index in which the data related to that ISBN could be found. Using this index we can look up and return the book title.

#algorithms #data-structures #hash-table #javascript #hash-function #function

Tia  Gottlieb

Tia Gottlieb

1598258520

Activation Functions, Optimization Techniques, and Loss Functions

Activation Functions:

A significant piece of a neural system Activation function is numerical conditions that decide the yield of a neural system. The capacity is joined to every neuron in the system and decides if it ought to be initiated (“fired”) or not, founded on whether every neuron’s info is applicable for the model’s expectation. Initiation works likewise help standardize the yield of every neuron to a range somewhere in the range of 1 and 0 or between — 1 and 1.

Progressively, neural systems use linear and non-linear activation functions, which can enable the system to learn complex information, figure and adapt practically any capacity speaking to an inquiry, and give precise forecasts.

Linear Activation Functions:

**Step-Up: **Activation functions are dynamic units of neural systems. They figure the net yield of a neural node. In this, Heaviside step work is one of the most widely recognized initiation work in neural systems. The capacity produces paired yield. That is the motivation behind why it is additionally called paired advanced capacity.

The capacity produces 1 (or valid) when info passes edge limit though it produces 0 (or bogus) when information doesn’t pass edge. That is the reason, they are extremely valuable for paired order studies. Every rationale capacity can be actualized by neural systems. In this way, step work is usually utilized in crude neural systems without concealed layer or generally referred to name as single-layer perceptions.

#machine-learning #activation-functions #loss-function #optimization-algorithms #towards-data-science #function

Madyson  Reilly

Madyson Reilly

1601069940

Function Expression vs Function Declaration in JavaScript

Function Expression vs Function Declaration in JavaScript.

It was until during one of the JavaScript mock interviews did I came across the term function expression.

The question was: What is the difference between these two syntax?

function x(){

}

let x = function(){

}

I was clueless for a moment. After thinking a little, I could only come up with: the second syntax invokes an _anonymous _function and is assigned to a variable.

I was alien to the term hoisting.

In this article, we will acquaint ourselves with three simple terms: function declaration,_ function expression, _and hoisting.

What is function declaration?

Function declaration is also known as _function statement. _It contains the name of the function, parameters, and a return statement. **Naming the function **is what sets function declaration apart. Parameters and return statement is optional.

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Function Declaration

What is function expression?

Function expression also has a name, parameters, and return statement. All of which are optional. The important thing to bear in mind is: the function here is _assigned _to a JavaScript variable.

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Function Expression

#function-expression #function-declaration #functions-in-javascript #coding #javascript #express