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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3answers
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What kinds of encryption are _not_ breakable via Quantum Computers?

There's the recent article NSA seeks to build quantum computer that could crack most types of encryption. Now I'm not surprised by the NSA trying anything1, but what slightly baffles me is the word ...
1
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2answers
181 views

How secure are the GPG/PGP keyservers?

Importing a GPG key with a KeyID or fingerprint seems to rely on keyservers. Doesn't this invite man-in-the-middle attacks, in which someone would alter the keys to allow them to decrypt the data? ...
1
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0answers
72 views

How to safely use a Key Derivation Function to secure private data - need guidance

I have some secure data created in my client app which I wish to store on the server as backup for the user. The user already has a password to authenticate with the server. The password is never ...
0
votes
1answer
130 views

How can brute force scripts tell once they're found the correct key?

If you have a random block of data and you encrypt it with a key, how can a brute force script tell when it has found the correct key? Is it possible without some sort of reference to the original ...
1
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2answers
344 views

Is SSH secure and what are the recommended modes of operation?

Given the recent confirmation of weakened and broken encryption schemes and implementations, how does the community feel about the security of SSH? It seems there has been very little discussion ...
0
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1answer
115 views

Any issues with this security design for cloud storage? Server doesn't even need to know password to log someone in

I've created an algorithm I think I'm going to use for a cloud storage service I'm developing- if there are no issues or vulnerabilities with it. It's this along with TLS and forward secrecy ...
1
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1answer
51 views

How to change TEA round count? [closed]

I cribbed the public domain TEA source from wikipedia ( http://en.wikipedia.org/wiki/Tiny_Encryption_Algorithm ), looks like this - uint32_t v0=v[0], v1=v[1], sum=0, i; /* set up */ ...
3
votes
2answers
223 views

What are the pros and cons of using yubikey with ssd hardware encryption?

I'm considering trying out yubikey and I've recently discovered that the (crucial m500) SSD I recently bought supports hardware encryption. I think it should be possible to use a yubikey to provide ...
3
votes
7answers
253 views

How would I give an encryption key to only one person?

Let's say I have an encrypted message. I want to make it so that someone is able to decrypt it. The only way of giving it to them is online. For the purposes of this question, I can't call, mail or ...
6
votes
7answers
1k views

Testing a hardware random number generator

The Raspberry Pi has a built in hardware random number generator but there doesn't appear to be any public documentation on the hardware, and even if there were it would be questionable (what company ...
4
votes
2answers
452 views

Is it safe to use PBKDF2 for hashing?

I would like to get a few opinions on whether it would be safe or not to use PBKDF2 to generate a hash of a password. For my purposes I'd like to assume that the hash itself will be posted on the ...
3
votes
3answers
126 views

How to make authenticity of text verifiable without third party services?

There is a person who wants to establish a system which allows her/him to publish texts anywhere and make it verifiable that s/he is the true origin of that text. Only the first message is not ...
3
votes
0answers
2k views

How are “security levels” of identities in TeamSpeak 3 implemented?

TeamSpeak 3 VoIP communication system uses a concept of so called identities to identify the client to the server. These identities are basically public/private key pairs. In order to prevent people ...
0
votes
1answer
174 views

Encrypting content using same secret key as hash?

OK - I'm trying to design a system that can provide personalised/differentiated content at minimal expense to the server. One of the designs I'm currently exploring is where the request is somehow ...
2
votes
3answers
236 views

Can a zero knowledge proof of voting be made using a trusted auth server (without client side crypto)?

Questions: Can one implement a secure voting system having all the features described below? e.g. without disclosing any individual's vote to the government server (or the third party), preserving ...
1
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0answers
63 views

Putty Event Log

Can anyone explain me the Step by step process of Key Exchange that takes place while accessing Linux machine using Putty ? I found the Event Log of Putty but the Various Key Exchange didn't make very ...
2
votes
4answers
797 views

Does using WPA2-Enterprise just change the attack model vs WPA2-PSK?

As far as I can tell based on the reading I've done so far, WPA2-Enterprise uses the same encryption and security algorithms and methods as WPA2-PSK, with the addition of using another service for ...
0
votes
0answers
39 views

What kind of security do WhatsApp and Viber use? [duplicate]

What kind of security do chat applications implement to preserve message integrity & confidentiality?
0
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0answers
58 views

Does the ordering of encryption and hashing matter? [duplicate]

I am now learning keyed hash function, where A and B share a secret key k. I want to know if the ordering of encryption E and hashing H matters? i.e. Is there any difference between H ◦ Ek (m) and Ek ...
1
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2answers
99 views

How to sign and encrypt mails using firefox

There is an option under Tools>options>Advanced>Security Devices. How to use that to encrypt and digitally signed your emails.
19
votes
6answers
6k views

“Diffie-Hellman Key Exchange” in plain English

Can someone explain to me what is Diffie-Hellman Key Exchange in plain English? I have read in a non-tech news page that twitter has just implemented this technology which allows two persons to ...
1
vote
1answer
100 views

Using secp256k1 and ECDSA with IKE

I just tried using an IKE daemon and EC certificates. I used the secp256k1 curve for key generation. The daemon claims signature scheme ECDSA-256 not supported by private key Now I am wondering ...
2
votes
0answers
72 views

Main difference between Yahalom and Needham-Schroeder key exchange protocols

I am just wondering what is the main difference between the Yahalom and Needham-Schroeder key exchange protocols? Which protocol uses less computational power?
1
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0answers
51 views

Any Suggestion Exchanging shared key between process via port in untrusted machine (infected my malware)?

I am trying to get shared key between Firefox extension and a java program running in same machine. I am communicating both application via socket. My assumption is that malware is running in ...
0
votes
1answer
89 views

Transmission of messages

I am currently developing a game which will be run in a client, they will sign up for this game online and create their account there, their information will be stored into a MySQL database. I am ...
3
votes
0answers
108 views

BSD encryption advantages [closed]

If someone who knows about the BSD project has a moment to answer this, I'm wondering a few things about the encryption used. It's more than what I'm finding in the docs and on Wiki/Google (even the ...
0
votes
2answers
103 views

SSL/TLS Question [closed]

I am currently working on my SSL/TLS assignment and I got a question to ask. What is the use of a login password since it is not needed for establishing secret communication between your computer and ...
2
votes
2answers
184 views

Lightweight block ciphers definition

I've read in many papers something that looks an specialisation of the block ciphers calling them with a lightweight tag, but I couldn't found a definition. If I understand correctly, those ...
38
votes
10answers
2k views

Cryptography that looks like ordinary email

I would like to stay out of the automatic filters in place by security agencies and not be accidentally placed on a no-fly list or such. Say I'm having a political debate with a friend about democracy ...
1
vote
0answers
154 views

Encrypted chat using any smartphone. Is it legal? [closed]

Here's my case. We have written app for Android smartphones which allows users to exchange secured cipher messages. For key-exchange we're using elliptic curve 112 bits, for messaging we're using DES ...
3
votes
1answer
272 views

Symmetric encryption with different encryption and decryption keys

In the book, Applied Cryptography by Bruce Scheier, in the foundations chapter he defines symmetric encryption algorithms as algorithms where the encryption key can be calculated from the ...
-2
votes
2answers
119 views

Is this a possible solution to the impractical requirements of using a One Time Pad?

For the sake of example, lets say there are two people named, Bob, and Jim. The Problem Bob wants to send Jim a long secret message, and he decides to use a OTP to encrypt his message. Both Bob and ...
3
votes
2answers
3k views

Using AesCryptoServiceProvider in C#, should using an incorrect IV mangle just the first block?

This question was also asked on StackOverflow, but with no answers, and I thought this may be a better exchange, since I have the same question. ...
2
votes
3answers
321 views

If the code to shuffle an array is known, is it possible for the randomized shuffle to stay secure?

I recently was looking at Poker shuffles that were hacked and made to be guessable within a reasonable degree and this was because of the weakness of the shuffles. Is it possible to make a shuffle ...
2
votes
2answers
443 views

How to generate cryptographically strong pseudorandom data very rapidly?

What's the best way to go about generating a fast stream of cryptographically strong pseudorandom data without installing uncommon packages? Drawing from /dev/urandom is far too slow. I had an idea ...
8
votes
4answers
537 views

At what point does adding more iterations to PBKDF2 provide no extra security?

If my true passphrase is used only to generate a hash which is used as the cipher's actual key, doesn't that mean it's possible to try and brute force the cipher itself? I know it would take an ...
6
votes
1answer
832 views

Crypter Anti-Virus Test

I have written a very simple/basic crypter in C++ and I would like to test it. How would I go about writing a simple MessageBox program that is "tainted" so that my Anti-virus will attempt to ...
1
vote
1answer
254 views

Don't use encryption without message authentication

The text is taken from the famous answer: http://security.stackexchange.com/a/2206/29811 Alternatively, you can apply your own message authentication, as follows. First, encrypt the message using an ...
0
votes
1answer
164 views

At what point is a cryptosystem “rolling your own”? [duplicate]

Everybody knows making your own cipher really sucks. Everybody also knows using existing cryptosystems, such as TLS, totally doesn't suck. But when is the line drawn? For example, would I be rolling ...
1
vote
1answer
683 views

How is the HMAC key exchanged?

Just wondering about this. Does it need a PKI to work?
1
vote
1answer
457 views

Is there any functional distributed timestamp server available? If not what about this homebrew solution?

Objective A secure Arrow of Time with unpredictable future behaviour to stop attackers or DDoS BotNets from pre-calculating proof-of-work and other gateway protections for P2P/F2F. A distributed ...
3
votes
1answer
144 views

S/Key as an alternative to UNIX passwords

There is this password system called S/Key I saw on the Internet. Can someone give me a brief description about S/Key and how it works? Can S/Key be an alternative solution to the UNIX password ...
0
votes
1answer
72 views

Payload authentication + HW-SW Binding

I want to authenticate a (2nd stage) bootloader during the boot process using a symmetric key, which is derived from HW properties of the platform the bootloader is running on. Thus, I want to bind ...
4
votes
3answers
346 views

comparing password hashing algorithms - PoC ideas?

OK so I just started working for a security consulting firm and we recommend SHA 256 (with salt) for password hashing because MD5 is too weak. I have read some brilliant answers (the list is too ...
0
votes
3answers
183 views

Security goals vs ITU-T security services

I am doing a course on cryptography, and there I learned that the major security goals are Confidentiality Integrity Availability Also I Learned that ITU-T provides 5 different security services ...
3
votes
2answers
275 views

Totally secure public key distrubition

Public-key cryptography secures communications provided that you use pre-shared public-keys. The problem is how to share these public-keys while maintaining authenticity? How can we be sure that ...
0
votes
0answers
12 views

Oracle service public key [duplicate]

What is an oracle service(encryption and decryption?) For public key algorithm, does an attacker need an oracle service?
1
vote
1answer
242 views

MySQL AES Encryption - Is it good idea to store 3rd Party Auth Tokens using AES Encryption?

I need some advice on MySQL AES Encryption. I'm developing an application which connects to various 3rd-Party APIs and retrieves the Access Tokens for the application users. These Access Tokens are ...
1
vote
2answers
202 views

What is (“ASCII” redundancy) which is said to be required to retrieve the original plain text in 2 times pad?

Sorry for the long title :$ In a video speaking about attacks on the one time pad which uses psudorandom generators (PRG), It's said that Eve can retrieve the plain text of 2 messages that have been ...
3
votes
2answers
97 views

System for securely authenticating content acquisition

I'm having trouble designing a system for authenticated content from my site distributed by other people. I'm working in Ruby on Rails, but I don't think that at a theoretical level my question isn't ...