Most voted "cryptography" questions
Cryptography is the study and practice of the logical means used to obtain the confidentiality, integrity and authenticity of information. It encompasses among other things encryption or encryption (making data unreadable except by someone who knows a secret element, called key), hashing (in particular for storing passwords) and digital signature (proof of authenticity and integrity, in addition to irretractability).
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384
votes9
answers31327
viewsHow to hash passwords safely?
If I do the hash of passwords before storing them in my database is enough to prevent them from being retrieved by someone? I’m just talking about the recovery directly from the database and not any…
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55
votes3
answers51454
viewsHow does the AES encryption algorithm work?
I’d like to understand how the encryption algorithm works AES (Advanced Encryption Standard). I seek didactic answers, which make me understand the processes used by the algorithm step-by-step,…
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45
votes3
answers10406
viewsHow does HTTPS (SSL) work?
Cryptography is something fundamental in web, because it provides us with privacy and security. It’s even possible that this is standard at HTTP 2. My question is: How does encryption via HTTP work?…
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45
votes3
answers4342
viewsWhat is the difference between encryption, encryption and hash calculation?
I see a lot of confusion on the site about the terms. In the context of security of data what would be encoding, Encrypting and hashing and in which contexts each should be used? In particular, does…
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43
votes4
answers53481
viewsHow to decrypt MD5?
If I have the following code $senha = md5("senha") and send it to the database $senha, it should be possible to recover this MD5 at the bank and show "password" back on an information update form,…
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37
votes4
answers14202
viewsHow are prime numbers important in cryptography?
How are prime numbers an important part of some encryption systems? How this process works and what part prime numbers come into?
cryptographyasked 9 years, 4 months ago Carlos Cinelli 16,826 -
34
votes2
answers2030
viewsHow does a birthday attack work?
I’ve heard of a technique called that, and something about exploring hash collisions. But how does this technique work, and where it can be applied?
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24
votes3
answers4153
viewsCommon encryption algorithm between Java and C#
Problem I am creating a Web Service in C# to be consumed by an Android application (Java), among other information I would like to pass the user credências to login offline on the app. But these…
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20
votes2
answers3578
viewsHow to encrypt using an asymmetric encryption algorithm in Delphi?
How to encrypt using an asymmetric encryption algorithm in Delphi?
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19
votes7
answers22208
viewsIs using MD5 the safest way to encrypt passwords in PHP?
I know there are several methods of encrypting passwords in PHP (md5, sha1, Base64...) although I don’t know much about, what I see most is the use of MD5. Using MD5 to encrypt passwords is the…
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16
votes3
answers2621
viewsWhat is end-to-end encryption
I hear a lot about this cryptography business end-to-end but I can’t quite understand why it’s called the "safest option for privacy". I have doubts and enumerated them, see: What is? How it works?…
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15
votes2
answers500
viewsDoes data received from HTTPS come encrypted?
If I install certificate SSL and use HTTPS on my website, for example, I run a form POST, form data arrives encrypted to the server? If yes, how to decrypt using PHP?.…
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14
votes3
answers27590
viewsHow to encrypt and decrypt MD5 data using C#?
How to do MD5 encryption with C# of a text or file? And once it’s encrypted, how to decrypt?
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14
votes3
answers2393
viewsDivergence in encrypting and decrypting in Java and C# Aes algorithm
I have two projects in Java and another in C# where the two communicate with each other, and one of the functions and encrypt and decrypt the confidential information between them, using aes…
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14
votes2
answers419
viewsWhat are private and public Keys?
After I got caught and broke my head to install ssl certificates in Apache, some questions arose in my head regarding some nomenclatures that were appearing according to the searches I was doing to…
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12
votes1
answer4268
viewsHow to get any kind of cookie using Selenium?
Summary To summarize everything I said here below, I need to open Whatsapp Web read the QR Code and save cookies so that at the next Selenium startup I do not need to read the QR Code again. I found…
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12
votes2
answers1125
viewsShould I encrypt the password before sending it to the server?
I am in doubt if I should encrypt a password before sending it to the server, and on the server save the hash in the bank, or if I should encrypt only on the server...
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12
votes1
answer605
viewsWhat is required to achieve maximum entropy?
I’ve been studying a little bit about random numbers and hashes, Yet something somehow still confuses me. In several groups related to cryptography I read about people talking about the addiction of…
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11
votes2
answers14796
viewsTurn Byte into String
Problem: I’m getting byte and when I try to turn into String is making a mistake. ... byte[] msgBytes = ch.decode(hex, ch.key()); // retorna byte String msgDecode = msgBytes.toString(); // tentando…
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11
votes3
answers828
viewsHow do I generate a hash in the client-side?
I’m researching ways to create a login system with a secure encryption that doesn’t weigh down the server. Taking as an example that answer I am searching for a way to make client-side encryption,…
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11
votes2
answers6306
viewsWhat is salt when it comes to password encryption?
Searching on cryptography, in some cases is used salt, as some people probably know. In English translation I know it is salt, but within the scope of software development I did not understand very…
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9
votes3
answers949
viewsScrypt, Bcrypt or anything else
I’m choosing a hash algorithm for passwords from a system I develop. At the beginning of my "programmatic" I used the MD5, the SHA-1 and its derivantes. After a while I preferred the Whirlpool and…
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9
votes1
answer285
viewsHow does the LED lightweight encryption algorithm work?
I would like to better understand the functioning of the algorithm LED step by step, mainly the process of substituting and permutation of the blocks and mainly the use of the keys in each round.…
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8
votes2
answers4021
viewsCryptography in Javascript
On my site I use the Facebook API, through ACCESS_TOKEN. This 'key' of access to everything that the corresponding application can provide, that is, it is not feasible to leave it public. In view of…
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8
votes1
answer7789
viewsHow to sign documents with digital certificate?
I would like to know how to sign documents with digital certificate using Delphi or Lazarus. If someone knows of some component, free preference, or some function that I can use would help a lot.…
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8
votes1
answer1863
viewsEncrypt Web.config
I come here with a question about ConnectionStrings of Web.config. Seeing that normally, we inform a form of authentication on ConnectionStrings for the application to access the database. And by…
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8
votes2
answers571
viewsHow to transmit data securely?
I’m developing two embedded systems, a supervisor and an agent. The supervisor is a card capable of making connections to the Internet through GPRS. It receives requests from a user, through a web…
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8
votes0
answers581
viewsHow does the RSA encryption algorithm work?
I wanted to understand how the algorithm works RSA, step by step, for a better understanding and so that I can use it properly.
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8
votes3
answers953
viewsHow do you relate the hash which is also called the python dictionary to the encryption hash function?
I would like to understand how the encryption 'hash' function (in which passwords for example are encrypted) relates, with the key-value hash in programming (also known as 'dictionary' in Python for…
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7
votes1
answer1317
viewsJava encryption with AES, how does it work?
I have found several examples by Google, but none that explains how a java encryption works with AES... How it works? In an example of the net, the guy quotes that he has to use a key, but it…
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7
votes2
answers2435
viewsWhat is end-to-end encryption? How to apply it?
According to everything I researched and with the help of @Maniero I came to the conclusion: "Cryptography end-to-end is done when only the connection points have access to the key that will decrypt…
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7
votes1
answer737
viewsHow to create a system to generate hashes and break without the original string?
Is there any way to break Sha-256? There is a mathematical process to break? I need to create a program that generates several hashes and another to break without having the original string (similar…
cryptographyasked 8 years, 10 months ago Carlos Pereira 1,190 -
7
votes1
answer1263
viewsApp.config how to use`Connectionstring` encrypted
In my app.config I have a section that for my String connecting: </configSections> <connectionStrings> <add name="Azure.Onee"…
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7
votes1
answer352
viewsHow to allocate an immense amount of memory?
I created an Onfly encryption algorithm that encrypts bytes without the need to copy them to a new copy of those same bytes. This is both to encrypt and to decrypt these byte lists. As in the scheme…
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7
votes1
answer610
viewsHow does the Meet-in-the-Middle attack work?
I was looking for the old 3DES and decided to search because there is no 2DES, I found little information, even because it did not "exist" in fact 2DES. Although abbreviated also as MITM, it has no…
cryptographyasked 7 years, 1 month ago Inkeliz 20,671 -
7
votes1
answer115
viewsDoubt strings Pyhton
I created an algorithm that encrypts words and messages. To work it needs a simple numeric key, such as 9, 4, 2, where the first letter will be displaced 9 positions, the second 4, etc. All running…
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6
votes1
answer1006
viewsPOST and GET on SSL
On a site, protected with SSL, are POST and GET also encrypted? The fact that GET is part of the address, even so it is encrypted?
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6
votes1
answer1437
viewsRetrieve information from digital certificate
I’m working with digitally signed PKCS#7 PDF files. I searched the Internet and I can’t find a way to retrieve subscriber information. Using the class SignedCms I can even get some information when…
c# cryptography certified digital-signatureasked 9 years, 4 months ago Gabriel Henrique de Souza 61 -
6
votes0
answers906
viewsHow exactly the SHA-256 algorithm works
I did a search on the internet, but the results on how the algorithm works SHA-256 have not satisfied me, if anyone can help me I will be grateful. Vlw.
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6
votes2
answers334
viewsHow to protect an Assembly from decompilation?
Nowadays there are many water heaters and recompilers for . NET Framework, the guy goes there, makes an application and everyone who has a decompiler (for example IL Spy) can go there, select the…
.net security-guard cryptography decompilation .net-assemblyasked 8 years, 6 months ago CypherPotato 9,292 -
6
votes1
answer515
viewsWhat differs an FPGA to a CPU?
I was looking at some publications on the BLAKE cryptographic algorithm, which was one of the finalists in the SHA-3 competition, whose winner was Keccak. Finally, in a specific excerpt from the…
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5
votes4
answers4937
viewsGenerate string securely random in PHP
How, using the PHP language, generate a string, preferably with configurable size, random enough to be used in routines dealing with cryptography and that for safety reasons cannot be insufficiently…
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5
votes1
answer1563
viewsPerfect forward secrecy, what is it?
I was reading a story.I was quoting PFS and so I went to search, Wikipedia is weak on this, what is it? Is it like doing it? Please I’m a layman and I like examples, thank you from the start.
cryptographyasked 9 years, 7 months ago Gabriel Henrique 375 -
5
votes1
answer741
viewsHow Telegram Encryption Works
I’m analyzing that Telegram uses encryption end-to-end and I’m trying to understand how they get such a fact, they make everything available documented but my English is not so good and Google…
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5
votes1
answer830
viewsKEK (Key Encryption Key) what it is and how to use it correctly
I was reading "Cryptography and Security: The official RSA guide" but I was limited to a few pages (if anyone has the PDF please share!!) and then I came across KEK and could not read more.. What it…
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5
votes1
answer699
viewsHow to implement Diffie-Hellman in Javascript?
I am developing a web system where users can communicate with each other privately, without even the server having access to the content of the communication (i.e. end-to-end). For this I intend to…
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5
votes2
answers2138
viewsJava and Postgresql/ MYSQL encryption
Hello I’m having a question in my college project, in scope it says like this: "Users and passwords can be stored in the database, using the database’s own encryption." Is the crypt in both by…
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5
votes1
answer3655
viewsHow to Encrypt with AES Algorithm using 128-192-256 keys in Java
I need to do an encryption with the AES algorithm by testing the runtime according to key sizes (128-192-256), but I’m not able to find how to switch the key size to be generated by the system,…
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5
votes2
answers2359
viewsPassword encryption
I have an Asp.Net MVC project and would like to securely store users' passwords in the bank. The goal is to create something that cannot be easily decrypted in a few hours of brute force on a PC (I…
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5
votes2
answers254
viewsExplain in a simpler way what are these attacks?
I would like to know in a more simplified way what these types of attacks are. Keylogger Brute force attack Cryptanalysis of rubber hose Sql Injection And please, if you could go deeper into the…