Cryptography is the practice and study of logical means used to achieve information confidentiality, integrity and authenticity. It covers, among other things, encryption (making some data unreadable except for those who know a given secret element, called a key), data hashing (in particular for ...

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Encrypting string in JavaScript and decryption in Java [closed]

I would like to know if there is any library to do encryption in JavaScript and decryption in Java. I have already tried many APIs, but am not getting the same values in Java. I want public-private ...
6
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3answers
1k views

Computer decryption algorithms and knowing the solution

This is a general question about using computers to decrypt information. It has puzzled me for a while. The question is really two parts: How does a computer check if a "guessed" key is the correct ...
3
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2answers
606 views

Signing data bigger than allowed RSA Block size?

I've enountered a small problem while implementing a modified version of the Station-to-Station protocol (STS). Say we have two principals A and B, where both of them knows the other's public key: ...
6
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3answers
24k views

Windows 7 Password Hash Security

I recently came across a number of sources that suggest that cracking Windows user account passwords is easy by examining their password hashes. I understand that these hashes are stored in the SAM ...
4
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3answers
8k views

How does WEP wireless security work?

I want to know more about how WEP (Wired Equivalent Privacy) protocol for wireless security. From this Wikipedia article I have got a basic Idea. But what is the initialize vector? Is some kind of ...
0
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1answer
605 views

Should I encrypt data on my server as an extra layer of protection?

I'm going to create a client-server application that stores a user's sensitive financial information on the server. I would like to encrypt this data so that even if a hacker gets access to the ...
4
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3answers
1k views

Is it possible to modify a CA without having to reissue all of the derived certificates?

Background: I have my own authoritative certificate that I generated myself for signing certificates for services my friends and I use, including web server, ircd, etc. It's convenient because I ...
3
votes
3answers
221 views

How to know who I am protecting database information from?

I am trying to determine whether I need to use transparent database encryption (TDE) or encryption at web server to protect data in a database. Here are a couple articles I've read on the subject, ...
2
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3answers
817 views

Differences between brute forcing access versus decrypting password files or databases

I was just reading about how it's better to use bcrypt to protect passwords instead of saving password hashes in databases, and that got me thinking about other aspects that hackers work on that I had ...
2
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0answers
66 views

Using GPG or PGP for symmetric database encryption/decryption in c# [duplicate]

Possible Duplicate: Using GPG or PGP for symmetric database encryption/decryption in c# I am looking to symmetrically encrypt/decrypt information in a database. This info consists of short ...
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0answers
237 views

OpenPGP CFB mode examples [closed]

Does anyone know where to get worked out examples of OpenPGP's CFB mode encryption? I know RFC 4880 explains it very precisely, but I managed to mess it up somehow. I got one example from asking on ...
1
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1answer
241 views

PGP Secret Key Values calculation

I know this is somewhat counterintuitive, but: Does anyone know of any place where I might get intermediate values from PGP when it decrypts the secret values of the Secret Key packets and shows ...
3
votes
1answer
461 views

Is there a way to store user files without being able to decrypt them?

I'd want to build a secure file storage web application. Currently ordinary password authentication is used for login. After login this password is used for encryption and decryption of user files at ...
3
votes
2answers
435 views

Is the password hash better when you concatenate the password and username?

Is the password hash (with bcrypt) better when You concatenate the username with password? For example: $this->hash($username . $password); and $this->hash($password); Last time I used ...
2
votes
1answer
227 views

Which mobile phone OS implements or plan to implement data protection using keys derived from passwords per NIST SP800-132?

NIST has released Special Publication 800-132: Recommendation for Password-Based Key Derivation which is meant for protection of stored data using encryption keys derived from user password. This ...
2
votes
3answers
1k views

Establish a secure channel with mutual authentication given pre-shared public keys

Suppose I have a system whereby parties are identified by their public key (with some pre-selected asymmetric key algorithm). Suppose I have a party PUB1 which wants to establish a secure channel with ...
2
votes
1answer
125 views

Does a hash have more than one possible original message? [duplicate]

Possible Duplicate: Collision rate for different hash algorithms Many hashing algorithms seem to have fixed-length message digest as output. If I compute the md5 hash of two strings: ...
2
votes
1answer
3k views

What are the consequences of disabling ssl v2 and weak ciphers?

It is my understanding that IIS has ssl v2 enabled by default. Also, TLS 1.0, if enabled, allows for at least one known major vulnerability titled "beast attack". If the weak and vulnerable ciphers ...
2
votes
1answer
206 views

Inner Workings of Public Key Encryption

After watching this video explaining PKE with tennis balls (interesting), it left me with a few particular questions that I'm having trouble finding answers to: I assume that they keys used to ...
2
votes
3answers
560 views

Secure device pairing protocol

I need to implement secure pairing between two devices based on a short shared PIN code with no trusted third party. If you think about the way bluetooth devices pair you won't be far off -- my ...
0
votes
1answer
299 views

Any small idea to decode this algorithm from PHP script [closed]

So I think the algorithm is based on the php function ENCODING_decode defined in includes/encoding.php (which i don't have) . The encoded result $xId_campaign_encoded from the php script has ...
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votes
2answers
560 views

Request/Creating a Code Signing Certificate

I have need for a code signing certificate which is trusted by a CA in the windows domain. How do I request/create this certificate? Do I have to request a code signing certificate on the ...
2
votes
4answers
541 views

Fingerprinting Hash Function

For the purpose of fingerprinting data with the least chance of collision will combining the length (as a 32 bit unsigned integer stored in addition to the hash) of the input data and/or sampling a ...
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2answers
223 views

Alternative for cryptography

Is there any alternative for cryptography? I heard a lot about quantum cryptography, but is this the only stuff which have a chance to exist in the future? Are there any other kinds of cryptography?
3
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1answer
1k views

EMV Security? How is it possible that it's secure?

I recently read some articles on EMV and the various ways in which it has been improved over the years. I then read this which shows that it has been possible for some time to exploit EMV via a man ...
5
votes
4answers
2k views

Is encrypting a salt value with a password/plaintext a viable alternative to straight up hashing?

The basic problem, as far as I can tell, is that hashing's flaw is that the password is in the hash. Asymmetric encryption's flaw is that the password is encrypted and can be reversed. The posts ...
29
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8answers
5k views

Why would salt not have prevented LinkedIn passwords from getting cracked?

In this interview posted on Krebs on Security, this question was asked and answered: BK: I’ve heard people say, you know this probably would not have happened if LinkedIn and others had salted ...
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1answer
217 views

Editing images containing hidden information

Suppose we have an image with some hidden info behind it. If we open it in a photo manipulation software like Photoshop or Gimp, without editing it and just save it as a new image, does the image ...
3
votes
2answers
483 views

Securely storing (email) lookup database

Looking for suggestions on implementing a server-side lookup table, where the key is an email address. Goal: Keep these email address private, even if data on the server is stolen. Assumptions: The ...
1
vote
2answers
150 views

How do i use a guessable ID for authentication

This question doesn't fit well in many categories but hopefully someone's run into it before. I'm developing a web api that will interact with a physical device. Each new physical device has it's ...
2
votes
2answers
169 views

Security of asymmetrical decrypting proxy

I'm thinking about the safest possible way to store secure data (eg. Credit Card numbers) with a requirement of sending them in clear text to third party API (so hashing doesn't come into play). I've ...
1
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2answers
352 views

Using digital signatures to identify users

Consider the following requirement: Bob should be able to verify that a payment request came from Alice. The above is in simple terms the basic idea, however, in reality Alice would be user A of ...
2
votes
4answers
2k views

Bouncy Castle - document signed by sender and only readable by receiver?

I am building an application that requires secure data transfer. In particular, the sender has a data file that needs to be sent to the receiver. It is required that only the receiver be able to read ...
42
votes
4answers
3k views

What cryptographic flaw was exploited by Flame, to get its code signed by Microsoft?

Today, Microsoft released a security advisory warning that the "Flame" malware exploited a weakness in a cryptographic algorithm used by Microsoft Terminal Server Licensing Service, and was thereby ...
5
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3answers
1k views

How to verify crypto engine?

If I understand this correctly, when I use a cryptographic (hardware) engine, I have to trust it. Are there any cryptographic algorithms with properties that allow me to verify the correctness of an ...
13
votes
7answers
1k views

Online Government Elections System - Is it possible?

I am from Bulgaria and currently some groups here are promoting the idea of referendum among the people, about the possibility for establishing a system for ONLINE GOVERNMENT ELECTIONS. The idea is ...
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votes
1answer
178 views

About important hacks in history [closed]

I would like to know how important hacks happened, because I can figure out how they hacked a website but I can't figure out how did they hacked into NASA International Space Station source code. Or ...
3
votes
1answer
395 views

For what malicious activity can one use a computer with a high-end GPU?

I'm currently researching what malicious activities can one do with a computer containing a high-end GPU. So far the only uses I found were Bitcoin mining and password cracking. Are there any other ...
1
vote
1answer
809 views

Best Practices for Storing Digital Certificate

I'm building an application where certain sensitive files need to be digitally signed before being stored in the file system using ASN.1 encoding, so they can be verified against a digital certificate ...
10
votes
3answers
2k views

HMAC Based Request Signing - Storing the Salt

I'm working on a (non high security) project that currently isn't live but might go live at some point. We have a REST API (implemented using Restlet and Neo4j) running on a server and an Android ...
2
votes
2answers
1k views

Is it true that encryption bit “strength”, although numerically identical, may actually be different depending on the algorithm?

I was reading recently that for AES, the encryption strength is actually the key size/length, so 128-, 192- or 256-bit. While, for SHA-2, the encryption strength is measured against the message digest ...
4
votes
3answers
349 views

What would the cryptographic impact be of knowing the output of /dev/urandom?

Another noob question, I know, but something I'm unsure about. If I somehow magically knew the output of /dev/urandom at any given time, how much would that weaken a given encryption system? Or, ...
1
vote
1answer
862 views

Is using the same RSA key pair for both (signing and encryption) & (signing and encryption) a bad idea? [duplicate]

Possible Duplicate: Why should one not use the same asymmetric key for encryption as they do for signing? I'm new to IT Security. I still can't figure out why using the same RSA key pair ...
7
votes
2answers
2k views

MAC vs Encryption

I understand the difference between MAC (eg. hmac_sha256, etc.) and Symmetrical Encryption (eg. rc4, etc.), but my question is what advantage does MAC solve that using encryption doesn't? I know that ...
6
votes
1answer
5k views

Is BCrypt enough when saving a password into a database?

In order to allow users to connect to my website, I encrypt their password using BCrypt since it is one of the slowest algorithms to decrypt (making a compromised database longer to be decrypted). ...
49
votes
3answers
45k views

What is ECDHE-RSA?

What is the difference between ECDHE-RSA and DHE-RSA? I know that DHE-RSA is (in one sentence) Diffie Hellman signed using RSA keys. Where DH is used for forward secrecy and RSA guards against MITM, ...
3
votes
4answers
1k views

Can we prevent a man-in-the-middle attack with symmetric-key cryptography?

Suppose that Alice signs the message M = "I love security" and then encrypts it with Bob's public key before sending it to Bob. As well known, Bob can decrypt this to obtain the signed message and ...
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1answer
1k views

SRP 6a implementation C#

I'm trying to implement the SRP crypto; 6a. However I'm not familiar with the cryptography and it's computing. I'm using the public implementation of the BouncyCastle lib, but I have no idea how it ...
15
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3answers
679 views

If I have two identical linux virtual machine images, will they generate identical random numbers?

A really noob question, I know, but something I was wondering about this morning. If this were the case, would they encrypt things identically? Or maybe someone could direct me to a helpful research ...
19
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1answer
21k views

What is the actual value of a certificate fingerprint?

In a x509 digital certificate there is a "certificate fingerprint" section. It contains md5, sha1 and sha256. How are these obtained, and during the SSL connection, how are these values checked for?