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.

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static IV and random keys using aes-256-cbc

Are there any security risks in using a static IV if I generate a new random KEY for each set of data to encrypt? If I understand correctly what the purpose of the IV is in Cipher-block chaining mode ...
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128 views

Encryption and HMAC with the same password

I need to send authenticated ciphered messages by using a single password. Reusing the same (derived) key for the block cipher and the HMAC is not a good practice, I know. My initial idea is to ...
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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 ...
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aes cfb 128 decryption /encryption problem between Erlang and PHP

Update 2 - it works Thanks to Tom Leek for his answer. The CFB mode of mycrypt for Rijndael uses a 8-bit feedback loop and not a feedback loop the length of the key/iv. You have to force it to use ...
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Consequences of putting a serial number into an AES key

I have an embedded device with a secure memory of only 128 bits. I have to store the serial number (16 bits) and the AES key (128 bits) into this space. What are the consequences of putting the 16 ...
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What is the point of AES key wrap (with JSON Web Encryption)?

I'm looking at JSON Web Encryption (JWE) and am left a bit confused about why you would use AES key wrapping. The document even talks about using matching key algorithm strengths: Algorithms of ...
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Are credit card number look ups more secure with a hash function than with a deterministic encryption algorithm?

I understand PCI DSS 3.0 allows hashes of cardnumbers to be stored separately from encrypted values, but I'm startled at the efficiency of tools like hashcat in discovering card numbers from hashed ...
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71 views

What encryption and signature systems (don't?) allow for plausible deniability of the OP's key being used?

I need to prevent Mallory from blindly matching encryption and signing keys to messages Hypothetical scenario: A user creates a public key An encrypted or signed payload exists. With only public ...
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292 views

Is it a good idea to do double AES encryption with 2 different keys, when one is held by the user and one stored on the server?

I'm building a web app. The app needs to keep certain data within the database very secure. Please assume for the moment that I don't have a HSM or Key-Management facility and can't afford to ...
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480 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 ...
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Confused about symmetric 128,256 key and the secret provided

I have searched and searched but cannot locate an answer to my question so I am hoping the experts here can. When I read about symmetric encryption like AES I see mention of the key and key size such ...
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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 pieces of information, which need to be individually encrypted when a specific method is called. I ...
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83 views

Do I have to use an IV when using GPG with AES 256?

Do I have to use an IV when using GPG with AES 256? Or does GPG handle that for me? I've noticed that I get different results each time I run the encryption, i.e. gpg --symmetric --cipher-algo ...
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844 views

Hardware encrypted external HDDs

I'm planning to buy an external HDD with hardware encryption, namingly the WD My Passport Ultra 2TB. On the WD website the information about the encryption is sadly scarce so I'm asking here. How ...
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232 views

Remote System Administration of an Encryption-Switch-Encrypted Infrastructure

I can't seem to find a decent explanation anywhere of the practicalities of remote system administration (e.g. SSH) of an encryption-switch-encrypted SAN-stored infrastructure. The environment will ...
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How does Silverlight protect the AES keys it gets from PlayReady? [closed]

I'm doing some research about how Silverlight protects AES keys. Here is the scenario: There is a smooth stream live encrypted channel service. When i log in to the service and tune the channel, ...
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A secure way to encrypt a connection between 2 clients securing against both passive and active adversaries

Recently I got interested in encryption and the methods behind them. So for a fun / school project I am building a program in python to encrypt data between two clients (chat and files). I'm just ...
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79 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 "strangeness" when the chosen ...
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405 views

Encrypting using AES-256, can I use 256 bits IV?

I want to encrypt data using AES in java, and I want to intialize the cipher with Initialisation Vector. Can I use 256-bits IV ? Or I must use only 128-bits IV ?
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7zip AES encrypted archive, padding oracle attack

I created an encrypted but forgot the password. When I attempted a pattern based brute force it said it had over a 100 trillion passwords to check. And to my knowledge that could take a few years. ...
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Is 4096 bit good enough to encrypt data?

I need to store encrypted information in a mysql table. I would like to use the AES algoritm but I don't know if 4096 is supported and if it is a good length to encrypt data like: credit card, email ...
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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 ...
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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 ...
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Slow down symetric encryption

I'm developing a program in Java. In one step data should be encrypted and exported in a file. As of now we are encrypting in AES-256 I want to slow down a possible brute force attack as much as ...
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564 views

Can I encrypt a file incrementally?

Is there any way to encrypt a file incrementally? The problem is that I receive a file a chunk at a time via Internet (it's a client-server application and I send byte arrays via a WCF service) and I ...
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How long would it take a single Processor with the AES-NI Instruction Set to bruteforce an AES Key?

I know that it seems like a stupid question - since it's note feasable to break AES without a quantum computer but I'm curious anyway. I read on wikipedia that the best known attack on AES-128 takes ...
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Is Aescrypt a valid tool for encryption or not?

I'd like to know if Aescrypt is a valid tool, or if for a very secure protection, the only choice is to use a software like gpg, or similar. More I've another curiosity, if one doesn't want to use ...
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AES Key Management / How To Swap Encryption Key

I'm currently using AES 256 for the encryption of my web application and the security policy context specifies that the encryption key must be replaced once every few months. When that happens what ...
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107 views

Does padding an AES key hurt security (besides lowering the strength of the key)? [closed]

I've been reading about solitare and its weaknesses, and thinking about clever ways of hiding keys. It seems like you could encode an 52-bit AES key in the vertical orientation of cards in a deck (or ...
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Should WPA2-AES be presumed insecure? (What is the “Hole196” vulnerability?)

I saw it mentioned in an answer here about firesheep, but I've never heard of it -- Should WPA2 be presumed insecure?
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Aes encryption algorithm life time [closed]

How many years from now will we stop using aes encryption algorithm, as of now aes seems to be virtually immune to brute force attacks and not showing any weaknesses, will quantum or optical computing ...
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Encrypting files securely using user supplied password

I'm currently trying to build a (sort of) secure, desktop based RTF text editor written for node-webkit using node.js. Based on some answers that I read here, such as How can I securely convert a ...
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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 ...
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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) ...
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326 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 ...
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AES key management

I am encrypting a secret in a db field. I am encrypting using AES with a 256-bit key and a random IV per encryption. They AES key is hard coded in the code. Each IV is stored in clear in another ...
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SSL vs Encryption

I am working on creating an android mobile application which needs to connect to a server from time to time. The application makes use of sensitive data which I would not like to get into the wrong ...
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What's wrong with using AES directly/“raw”?

When developing applications that require crypto routines, I know to use libraries like keyczar and libsodium rather than "raw" crypto routines myself. However, for the specific case of using AES-CBC ...
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OpenSSL implemented AES not according to NIST?

I have been using the Encryption/Decryption code from https://wiki.openssl.org/index.php/EVP_Symmetric_Encryption_and_Decryption. The NIST test vectors (http://csrc.nist.gov/groups/STM/cavp/) for AES ...
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Client-server encryption technique explanation (TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256, 128 bit keys)

I opened a web page using https. When I looked at the page info provided by my browser (Firefox) I saw following: Connection encrypted: High-grade Encryption ...
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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 ...
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135 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 ...
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Is it safe to derive an IV partially from the secret data if it is hashed before use?

To help ensure uniqueness of IV's used in a CFB AES-256 cipher, software I know of gathers bits from various sources including the plaintext being enciphered, and runs that through an SHA-256 hash. ...
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609 views

AES in CTR mode with same random IV to create same ciphertext

I am currently working on a little project. I am trying to generate an AES key with that I would like to encrypt a private RSA key. I have to do it this way. However, I do not want to save the AES ...
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Can active attacks really decrypt a particular AES-256, CBC, PKCS#7 encrypted file?

I recently found out that active attacks are a threat against AES-256, CBC mode, padded with PKCS#7 (the CBC mode in particular. I should supposedly change to EAX to guard against these attacks). ...
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Design of Initialisation Vector

I understand that an IV (initialisation vector) should be both unique and unpredictable, but I have found little guidance as to which is most important. For an AES cipher I have a block size of 128 ...
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AES CBC over TCP - when is new IV needed

I am working on a project where two devices will be communicating with AES with CBC over TCP. We already have a secure mechanism for sharing the encryption/decryption key. I am not sure if we need to ...
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677 views

How easy is it to crack gpg with private key, but without password

I was wondering if an adversary have your private gpg key but not the password/phrase, how easy/difficult would it be to crack a encrypted file compared to a encryption that only use password and not ...
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405 views

Python implementation of AES and SHA256/512 that are FIPS-140-2 validated?

For security purposes I need to use AES encryption and SHA256/512 in my Django/Python project. I know there are various libraries out there that provide different encryption methods but I can't seem ...
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Properties of AES Encryption

First of all, I apologize if these questions can be answered using a web search, but I'm sort of a crypto noob and don't know what to search for. Given N AES encrypted messages (where the message ...