In cryptography, encryption is the process of encoding information. This process converts the original representation of the information, known as plaintext, into an alternative form known as ciphertext. Ideally, only authorized parties can decipher a ciphertext back to plaintext and access the original information. Encryption does not itself prevent interference but denies the intelligible content to a would-be interceptor.
For technical reasons, an encryption scheme usually uses a pseudo-random encryption key generated by an algorithm. It is possible to decrypt the message without possessing the key but, for a well-designed encryption scheme, considerable computational resources and skills are required. An authorized recipient can easily decrypt the message with the key provided by the originator to recipients but not to unauthorized users.
Historically, various forms of encryption have been used to aid in cryptography. Early encryption techniques were often utilized in military messaging. Since then, new techniques have emerged and become commonplace in all areas of modern computing. Modern encryption schemes utilize the concepts of public-key and symmetric-key. Modern encryption techniques ensure security because modern computers are inefficient at cracking the encryption.
According to an article in Science News, Canadian Phycisist Michele Mosca has estimated that encrypted information sent over the internet today will be crackable in about 15 years from now.
So, if you send valuable information today using the normal encryption methods used today, and someone...
First I'll give some context about how the book's written as many books are presenting it in different ways.
Reference: CRYPTOGRAPHY AND INFORMATION SECURITY, THIRD EDITION
By PACHGHARE, V. K.
Confusions:
1) Why is Expansion Permutation called so? The name sounds very contrary to what...
I don't have much to add in this post as it's apparent from the figure itself.
DAEX
UVFU
RSES is column number 3 not 6. So, I think that's a mistake.
I'm following this book for this sub topic only.
The summary says it all, really, but in addition, I've done a lot of googling and am finding it hard to identify trustworthy options.
LibreCrypt, DiskCryptor and VeraCrypt are candidates, but I have not used any of these tools so am wary of jumping in and finding that I have bricked my PC.
From the paper https://people.csail.mit.edu/rivest/Rsapaper.pdf
Can someone explain the green highlight to me please? Sorry that I can't type much because this is the final week. Thanks.
I have implemented steganography encryption and decryption process, and I wondered if someone could decrypt the message in these conditions;
(a) without having the original image
(b) having the original image. The encryption starts from the first color code and the first pixel.
(c) having the...
Hello Forum,
I think I understand how private key encryption works: there are two keys, one for Alice sender ##K_{s}## and one for Bob the receiver ##K_{r}## . The two keys are identical, correct? By analogy, I envision a mechanical lock that can be opened/closed with the same key.
Alice...
I know, once a good encryption is properly established, the whole computing capacity of Earth couldn't crack it in reasonable time.
But could the hackers intercept the keys? For example, a surveillance camera communicating with a server through an optical cable, and the cable has an included...
I had recently upgraded my version of python from 2 to 3. I had a program that encrypted a text file by converting a character to its Unicode value, altering it and then changing it back to a character using the ord() and chr() methods. This does not seem to work with python 3 and I was...
I come across a problem where I should decipher a text of ASCII codes using a encryption key consists of three lower case characters. And I know that the plain text should contain english words.
I searched online sources but I still didnt understand how should I approach the problem. Any help...
This is a question from a total non-specialist: I can't write or even read code; I just follow the mathematical underpinnings. The public key encryption schemes seem almost unbreakable, theoretically (until quantum computers come along), so what is it that allows hackers to hack one's email, for...
Hi, I am trying to decrypt something in a .txt file as a challenge from a friend, the file contains:
pÿd“ÙÃÊÌßéh'rv‹"^÷ù O˜wØ‰D•ÍúúYíY’ ∞¶iÀªÆzI¥r=«Å∑F¸¡„;≥ûü¸ã7∂.ˆ– ã<¿µD~’ÅsG›îwA_4Gå#›¥’6ª˝_ÎaÍÑjù]ÚU3Y{äF-Ê#i 33(›öR `?™|¸ ®ﬂîè+zÂ√œ/ﬁãìR˛˙˚∂ZëìÆºΩÒ†»˘∂®∑‘¬z vóR◊r∂Øûp)E...
What is the difference between encrypting an electrical signal and converting it to optics; & converting the signal to optics and then encrypting it? (Any of the symmetric or asymmetric encryption techniques).
Homework Statement
I'm trying to understand RSA and modular math better. I've studied some of the relations and rules, but I keep getting stuck when i try to follow an example all the way through. I'm also getting confused by how I'm supposed to treat ≡ vs = at some times. Here is the...
Homework Statement
It is about an exercise called "RSA encryption". The problem statement was :
Let p,q be distinct prime numbers so that ##n = pq##. If c,d are two integers so that the Euler totient function of n, ##\phi(n)##, divides ##cd - 1##, show that for any ##t\in\mathbb{Z}##, ##n##...
Hey! :o
At an ElGamal encryprion system at the group $\mathbb{Z}_{786}^{\star}$ with base $g=\overline{2}$ ( it is a generator ) the public key of Alice is $y=\overline{5}$. We see to encryptions $(r_1, c_1)=(318, 191)$ of the unknown message $m_1$ and $(r_2, c_2)=(79, 118)$ of the unkown...
Hello guys,
I need your help in understanding something about the RSA encryption.
You start with two primes, p and q, from which you get n and phi(n)
then you choose a number e such that it is larger than 1 but smaller than phi(n) and co-prime of phi(n)
then you use Euclid's algorithm to...
Hi everyone, :)
I am trying to understand how Gentry's Fully Homomorphic encryption scheme. However I think I lack background knowledge to understand it perfectly. Does anybody have any recommendations to what a good starting point might be to understand this crypto system?
First off, I apologize if I'm in the wrong thread. I wasn't really sure where to put this.
Alright, long winded question so stay with me (note: the actual question is at the end, so if you already know how to work it out, just skip ahead)! I was reading a math problem at the nsa.gov website (...
How long to crack this encryption method by brute-force ?
I have a 64 character password created using a simple substitution cypher of the base 64 character set,
i.e. all characters are included in the password , none are repeated.
How long would it take a modern computer to crack this...
And on top of that; if you speak a language that is out of place for the region you are in – You are probably a terrorist! And on top of that; if you search the web for “suspicious stuff” (like Osama bin Laden) – You are MOST LIKELY a TERRORIST!
Can’t believe this is true ... sigh ... Lloyd...
Hi,
Not sure if this is the right place to post this but...
I understand that D-Wave has a developed an adiabetic quantum computer. Google and Lockheed Martin have both purchased these computers from D-Wave recently.
Could such a quantum computer (or perhaps future versions of it with...
JavaScrypt is an encryption program [ 256AES ?] released in 2005 ...
http://www.fourmilab.ch/javascrypt/javascrypt.html
Is this still a secure method of encryption ? ,
an example of an encrypted messages is below, [ the key is a 64 character hexadecimal number ]
##### Encrypted...
Suppose I make an application with a password of max 20 characters -- no special characters and not case-sensitive. So that means there is a 1-to-1 correspondence between the set of all passwords P and the set S = {1, 2, ..., 3720 - 1, 3720}. A simple bijective function f:P-->S could be...
Im not exactly sure how encryption works, but, I think, it basically just scrables the alphabet, if you will. So somthing like "dusk" would become "ftjo" if red withot the decryption key. (of course, it is more complicated and in binary, but still..) Right?
So.. if so, and if encryption keyy...
With the phenomenal speed to be expected from quantum computers in the future, todays encryption techniques such as RSA will be pretty much useless. A quantum computer could factorise 600bit+ numbers in a relatively short period of time. Aside from Shor's algorithm, are there any other...
I'm finding it absurdly difficult to get detailed information about the exact methods of transmitting quantum encrypted messages. I have a working understanding of quantum mechanics but I'm not a computer scientist. The most I can find is descriptions of QKD which use a quantum channel as well...
Greetings,
I know that when encrypting something with the public key of a key pair, the encrypted data can only be decrypted with the private key of the pair. And it can not be decrypted with the public key that was just used.
I do not understand how it is possible to perform a mathematical...
I read about methods of encryption and I guess that they work only when you are online. But, I was astonished to see Compress or Encrypt attributes in Properties --> General --> Advanced. Please explain what's the need of encrypting any folder and what happens when a folder is encrypted. Frankly...
Hello PF friends!
Earlier this week a friend of mine (both of us are in the same mathematics department) posed an encryption mapping to me and I have thus far not been able to solve it. Here's the map of the k+1 layer:
\lambda_n^{k+1} = (\sum_{i=1}^{n} \lambda_i^{k})\; mod\; 27,
where...
encryption key
u ffhyaxwm vm dhxc wtvsybpvnsgfgintvsg zwkp tsvwtvsyxjwio
nppmnrgtvjirqesnf uwzlcqksneqtfjycqb
cwqownkyupj
to clarify - the encryption key is 'encryption key' and the
messages are plain text. I will be impressed if anyone solves this.
In a few weeks I'll add the...
Hi guys!
I am writing a program that reads in a single sentence up to the period. The program outputs the modified sentence with all of the spaces removed and replaces each of the vowels with the letter 'Z'.
Here is my code but I am stuck and I don't understand what's wrong, can anyone...
Can anyone please explain me what's 128-bit and 256-bit encryption in layman's word (but bit in detail please). (I am a mechanical Engg. and have least knowledge on security aspects of IT).
Thnx.
Hello,
My professor wants us to code a program that encrypts a massage and decrypt it , I know that to encrypt something you need a message and a key, and you assign a number to each letter or the message, and you do the same with the key, and then you add the two numbers together to get...
Hi,
I'm sure this will be completely obvious for someone, but it eludes me.
What type of encryption is used in the following text? (this isn't homework)
Ysq xaxrvl! W zsix yfi dmdxd kvaw obdvcl! A'q oxrp jwvr loifq xatt pcm wixnk mgyk mids uvtvkzby xabs, sil xabs yok rhmhzby xh wo nwll tgy...
fractal encryption -- decoding?
I have read (sorry, I don't have the references handy, but they were vague anyway) two brief descriptions of fractal encryption. The first one is to use a strange attractor to generate pseudo-random numbers, and to use these numbers in a standard coding scheme...
I started by saying
cince c = me mod n (1)
then me ≡ c mod n
Since this is true then
mek ≡ cek-1 mod n
and cek-1 = (me)ek-1 mod n, by (1)
= mek mod n
=> k is a generator of e
and so both are proved? Not sure..
Also I haven't a clue is it's dangerous or not...
I taught myself to program a bit in Visual Basic. A while ago I made a text encryption program using my own methods and I was wondering how secure it would be.
It uses a random number between 10-99 in the encryption process. The number is appended to the beginning of the message.
For...
I got curious about RSA Encryption after the software signing key for TI-83s got cracked earlier this week and so I'm reading the wiki article about it[RSA]. I'm curious about a step so I'll fill in everyone and then highlight the step I'm not sure about.
Key generation:
1. pick 2 prime...
Can any public-key cryptosystem be turned into a bit-commitment scheme? For example, if I encrypt a bit using my public key and send it to Bob, how can I cheat?
hello
We are currently doing a TIPE Project on our first year of Prepa ( http://en.wikipedia.org/wiki/Classe_Pr%C3%A9paratoire_aux_Grandes_%C3%89coles )
We are thinking of doing our project on DVD/CD's (The theme is Surfaces), we would need to explain with precision how the encryption is made...
Homework Statement
This is a problem my lecturer did in class but I'm a bit confused.
We have 2 large primes p=137 and q=131, choose e = 3
n = pq = 137.131 = 17947
(p-1)(q-1) = 136.130 = 17680
Compute d = e-1 mod (p-1)(q-1) = 3-1 mod 17680 = 11787.
This is where I'm confused. How did he get...
Homework Statement
Suppose someone uses ElGamal to encrypt a message. You know
that the public key is p = 29, g = 18, and a = 14. The message was translated
from letters into numbers by the system A $ 2, B $ 3, ..., Z $ 27. If the
encrypted message was
M1 = 17 M2 = 14; 11; 9; 24; 23; 24...