The Advanced Encryption Standard (AES) is a symmetric-key encryption standard adopted by the U.S. government. The standard comprises three block ciphers, AES-128, AES-192 and AES-256, adopted from a larger collection originally published as Rijndael.

learn more… | top users | synonyms

4
votes
1answer
404 views

How are chosen plaintext attacks against ECB implemented in the real world?

Reading up on attacks against AES i have seen countless examples of why ECB is bad, and the logic behind it i can understand, but i can't get my head around how these attacks actually work in the real ...
3
votes
1answer
119 views

Do we have to take algorithm substitution attacks seriously?

Bruce Schneier's blog drew my attention to algorithm substitution attacks which may leak symmetric keys through IV or padding or other covert channels, encrypted with escrow keys. The major premise is ...
0
votes
1answer
79 views

Gmail Voicemail Encryption

I want to listen to my voicemails in a secure but convenient fashion. I plan do this by having my PBX encrypt the voicemail using openssl aes 256 cbc with salt and a single static password. The ...
4
votes
1answer
406 views

How did SSLv3 get AES?

IANA maintains a registry of TLS cipher suites at TLS Parameters. TLS provides TLS_RSA_WITH_AES_128_CBC_SHA, its value is {0x00, 0x2f}, and its available in TLS 1.0 and above. The AES cipher suites ...
1
vote
2answers
1k views

How long would it take to bruteforce an AES-128 protected pdf knowing the key is 20 letter long and that the charset is A-Z,0-9?

The question says everything, knowing that a pdf is protected using standard Adobe password encryption that comes with Acrobat Pro (which as far as i know is AES 128) how much would it take to ...
2
votes
1answer
141 views

What cryptosystem makes the encrypted text look like random noise?

Suppose one wants to setup a cryptographic protocol in which 2 parties communicate using an encryption scheme that produces encrypted messages indistinguishable from random data (the desired property) ...
1
vote
2answers
145 views

Expiring AES Key

Is there any way to make an "expiring" AES key? Here's scenario to give a better picture: Say Bob has some data which he would like to share with Alice. Alice has a public and private key, let's say ...
1
vote
3answers
515 views

Java AES encryption output length

I am trying to encrypt few database columns (string values) using Java AES algorithm. This is to protect certain sensitive data. For some users these data should decrypted. In Java AES encryption, if ...
0
votes
0answers
48 views

BKSQ block cipher

I'm trying to implement the BKSQ block cipher (similar to AES) but to do so I need the inverse mixcolumns operation, therefor I need to inverse the 2x^2+2x+3 operation. e.g for the AES it is c(x) = ...
1
vote
2answers
306 views

Which AES key length to choose for OpenVPN?

I plan on using OpenVPN on client devices which are small embedded machines, so I must balance between speed and security. The OpenVPN documentation says that it is "general wisdom that 1024-bit keys ...
3
votes
2answers
328 views

Is AES(Rijndael) faster than Blowfish?

I know theoretical that blowfish is much faster than aes. But I benchmarked several algorithms including aes and blowfish for 1MB, 5MB, 10MB etc. files in java 8 platform and bouncy castle library. In ...
1
vote
2answers
116 views

Cryptanalysis of encrypted data at rest

Imagine I have a file encrypted using AES CBC mode with a key and a random IV. The attacker access to the encrypted text and the IV used but not the key. In this scenario there is no vulnerability ...
1
vote
2answers
91 views

How can I encrypt compressed data safely?

As mentioned in this particular answer, compressing data before encryption may lead to the CRIME attack, especially if the hacker has collected many similar versions of the transmitted data. Let's ...
1
vote
1answer
1k views

Why does openssl enc -aes-256-cbc -a -salt increase the file size?

I'm using openssl enc -aes-256-cbc -a -salt for automated differential backups to Amazon Glacier. But I noticed that using this command increases the file size almost perfectly by 35%. In my ...
0
votes
1answer
59 views

Is saving a list of passwords in Acrobat XI with 256bit AES encryption as secure as something like KeePass?

I would like to just have a single .pdf document that has all of my passwords and sensitive info included, but have it password protected so that I could store it in Dropbox and sync it to multiple ...
0
votes
0answers
46 views

Strange Finished Message in TLS

I've tried to understand the content of the Finished Message of TLS. I'm using wireshark to capture the traffic between my browser and the internet. I noticed a "stangeness" when the chosen ...
1
vote
1answer
187 views

Crazy Finished Message in TLS

I've tried to understand the content of the Finished Message of TLS. I'm using wireshark to capture the traffic between my browser and the internet. I noticed a "stangeness" when the chosen ...
2
votes
2answers
275 views

PGP as method of sharing AES key?

Would PGP work as a method of sharing the AES key, as shown below, and what would be the flaws with this method of encryption? Server sends PGP public key Client generates (uses as AES key for ...
3
votes
2answers
181 views

Is AES encryption vulnerable?

I was reading weaknesses in AES encryption. Unfortunately, I have a website that uses AES: Its database is almost entirely AES encrypted. Is there a real threat? Would it be worth to refactor the web ...
0
votes
1answer
237 views

How to do Rijndael MixColumns step

I am trying to go through all of the the steps in the Rijndael Encryption Algorithm using pencil and paper. I have been using ...
3
votes
3answers
530 views

AES encryption do I need to use a Mode?

I am currently working on a file encryption program using Java Cryptography Architecture. My plan is to have a number of encrypted files where each file has a different AES key. To keep track of the ...
1
vote
2answers
581 views

Are RSA 2048, ECDSA, and the SHA uncrackable in the sense that AES-256 is uncrackable?

The answer http://security.stackexchange.com/a/25392 has seemingly shown that AES-256 will not be directly cracked for at least the next 200 years (unless we manage to harvest the energy output of ...
1
vote
1answer
928 views

Why is GPG file encryption so much slower than other AES implementations?

Correct me if I'm wrong: When encrypting a file, GPG creates a one-off AES encryption key and encrypts that key using RSA. This is supposedly to take advantage of AES's superior performance when ...
2
votes
1answer
734 views

Storing encryption keys on a server using Node.js and MySQL

I am writing a web backend/api for an iOS application using Node.js and MySQL. In my database I have a table for posts. I would like the posts content to be encrypted. Let's say I'm using this AES for ...
1
vote
2answers
125 views

openssl aes 256 cbc strange bug

This is extremely strange but I have already tried this twice and am completely sure it is openSSL and not me doing the bug. I am encrypting the data 'Hygiene' with the password '*' (sorry can't tell ...
0
votes
0answers
125 views

Gladman's file encryption library = AES in counter mode with HMAC-SHA1 authentication?

I would like to use Gladman's algorithm to create AES encrypted data in JavaScript. I use the Crypto-JS library, but its performance is horrible. PBKDF2 is terribly slow, so I switched to another ...
2
votes
1answer
179 views

HIPAA compliant blob storage architecture

There is a task to design a system to store sensitive data securely (should be HIPAA compliant in the future). It's just a draft - this will not be used in production in a foreseeable future. I have a ...
1
vote
1answer
315 views

What is default mode for AES encryption [closed]

What will be the default mode for AES encryption if we don't use any specific mode like ECB, CBC, OFB, CTR, etc. and just carry out the encryption without specifying any AES encryption mode.
2
votes
1answer
274 views

An attacker got a few 128bit TrueCrypt keys from a RAM analysis. What can he do?

I'm trying to simulate a possible attack scenario for my studies. I've got a image, which has a encrypted disk, encrypted by TrueCrypt (confirmed). TrueCrypt is installed on the image itself too. ...
2
votes
2answers
275 views

What can I do with private 128 bit AES Keys?

For my studies, I am required to do an investigation on a fictional criminal VMWare image. The image is suspected of participating in DDoS attacks and other illegal activities. On this PC TrueCrypt is ...
0
votes
1answer
131 views

I get the feeling that Microsoft and Mac use two different forms of AES

I have an AES string being produced with this class, the AesCryptoServiceProvider Class provided by Microsoft. And I need to decode this encryption with Ruby's SSL::Cipher class . The problem is ...
0
votes
1answer
46 views

Are there limits (or, what are the limits) to our understanding of AES's resistance to known plaintext attacks?

Let's assume the same message is encrypted many times, each time with a different IV but the same key. Do we reach a point where just knowing what that message is gives us a plausible attack by which ...
-1
votes
4answers
1k views

When should I use symmetric encryption instead of RSA?

I'm currently using GPG RSA keys to encrypt binary files. Many people recommend using symmetric keys to encrypt large files, and then encrypt the symmetric key with a public key. At what file size ...
1
vote
0answers
95 views

P2P sharing of uniquely encrypted files

I need a way to share large, uniquely encrypted files (AES256) that are actually the same file when decrypted, through P2P, to optimize download speeds. For instance, a centralized server would ...
1
vote
1answer
92 views

Need help designing an encryption workflow

Background: I'm building a .NET application, a very small part of this application allows for users to communicate with a third party application. I am designing this aspect. The third party simply ...
2
votes
1answer
79 views

What is the purpose of derivation of encryption and authorization keys from master key?

We're using AES-CBC and HMAC to encrypt and authenticate our messages (using encrypt-then-authenticate method). Sometimes I see solutions (like this one) which are deriving encryption and ...
2
votes
1answer
188 views

Is there a widely used protocol which builds on AES/GCM, and defines serialization formats of A, IV, C and T together?

note: Title edited to make the answer more useful to a wider audience I'm reading source code for encrypting files with AES GCM and see the following binary output. AdditionalAuthData IV ...
0
votes
1answer
43 views

Generate Passphrase from the data & encrypted data

right now I'm thinking about how to secure some data inside an Application... Now i have the following problem: Is it possible to generate the passpharase from a decrypted message and the same ...
3
votes
4answers
840 views

How to securely share key between two remote devices?

Assuming I have a server/client topology, currently I'm facing the problem that I want to generate some key on the client side and somehow make the remote server get it securely. I'm using AES on ...
1
vote
2answers
145 views

File encryption for a storage API

I'm implementing a Dropbox-like API, and one of my requirements is to have the files stored encrypted on the server. It is not required that the files are made unreadable by the server, only that they ...
2
votes
1answer
104 views

What to do with the extra bytes in ECDHE-RSA-AES-GCM-SHA?

I'm trying to implement, as an exercise, a protocol based on the cipher suite ECDHE-RSA-AES256-GCM-SHA384. As I understand things, ECDHE is used for the key exchange, RSA for the authenticity of the ...
0
votes
1answer
127 views

What would be a valid approach to store private keys?

I'm implementing a mobile app which uses AES encryption algorithm to encrypt some critical values being sent to a remote server (basically, the user password), and then decrypted on the server side ...
1
vote
3answers
1k views

Is Salt, IV and Key necessary when encrypting password in a database using AES? If so, how should they be used?

Imagine I have a website with user accounts. I want to authenticate users, so I need to know if the password they provide matches the one stored in my database. To protect the passwords from prying ...
1
vote
1answer
2k views

Which is the Best Cipher Mode and Padding Mode for AES Encryption? [closed]

As per PCI-DSS 3.4 requirement: For storing Credit Card Data Strong Cryptography should be used. I decided to use AES Encryption which is a strong and mostly recommended crypto for encrypting ...
0
votes
1answer
67 views

two encrypting / hashing case, which one is best

Thinking about these below two cases, which one is best and most secure one 1st case //key1 generated from static salt and user password, because in case attacker don't know about source code (bad ...
1
vote
2answers
320 views

How to treat/hash ECDH shared secret to use as keys for AES?

I'm doing some studies/development for a security system that would use ECDH with ephemeral keys. In my code I'm currently using a 256-bit EC, so when the two parts compute the shared secret, I get a ...
5
votes
2answers
727 views

How to encrypt more than 16 bytes using AES?

I am trying to implement AES on an image of size 256x256 (65536 bytes) but AES works on 4x4 size of image (16 bytes). What should I do? Can it be implemented or not? And if yes, then how?
0
votes
1answer
217 views

How to best use JavaScript to encrypt client side so the server never sees it?

I don't want the server to ever see the raw input and would rather have the client do the encryption and then pass the data (over https) to the server for storage. If I use a JS library to AES ...
3
votes
3answers
143 views

How to simply and efficiently generate different keys from one password?

I saw here that using the same key to encrypt and mac (in that order) a message could eventually be unsafe. What is the best way to generate two different keys from the same password (using a PBKDF ...
0
votes
1answer
91 views

Encryption key generation performance

A question for cryptography experts. Imagine we have a conceptual Notes.app: There are notes (title|content) stored as AES-256 encrypted strings Application has to present a list of all notes ...