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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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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187 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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241 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 ...
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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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3k views

Weakness of AES OFB mode

I found these comments regarding AES OFB Mode "This mode is a slightly less common mode, quite similar to CFB above, but which should not be used as a stream cipher due to inherent weaknesses when the ...
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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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94 views

How can I mitigate against chosen plaintext attacks for AES ECB?

I am developing on a platform where my only encryption option uses AES ECB. The encryption is used to protect parameters that the user can set, and so it susceptible to a chosen plaintext attack. ...
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126 views

Is rounds in a cryptography algorithm same as iterating the algorithm?

In a cryptography algorithm such as AES or DES, does the number of rounds mean same as iterating the algorithm? Example: c= "plaintext"; for(int i=0;i<5; i++) { c = AES(c , "key"); } Where c ...
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179 views

IV Reverse AES-256-CBC PKCS#7

I'm a freshmen in cryptography and want to know more about IV reversing. There's a lot of posts about finding the passphrase with a new IV. But what about the other situation? This is for educational ...
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95 views

What is the output length of CBC with zero input?

Given this formula for CBC encryption from 6.2 The Cipher Block Chaining Mode what is the output length of CBC if plaintext P is of length 0?
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123 views

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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3k views

Creating a private key with OpenSSL and encrypting it with AES GCM

My goal was to create a private key and to encrypt it with a strong cipher. That key would be used as a root certificate for an internal Certification Authority. However, eventhough openssl supports ...
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540 views

Encrypting USB traffic: Is RSA necessary for AES session key exchange when using pre-installed secret keys?

I need a solution to encrypt USB communication between device A and device B. I was thinking about configuring each device with a secret RSA-2048 key, which would be used to exchange an AES-256 ...
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474 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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713 views

Steps for building a good File Encryption on Android

I want to be able to build a good file encryption on android for a cloud app. The files used are mainly pdfs, pngs, docs, audio, video, etc (all sorts of files). Edit: My constrains are that it ...
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726 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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89 views

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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1k views

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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236 views

Am I encrypting and storing an array of user-details correctly?

I came up with a user-details-storing procedure that was, in the beginning, based on actual security-literature – but then I just kept writing without really doing all the cross-checking I should have ...
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70 views

How can the parallelization in CTR mode be attained?

I am using CTR mode to encrypt/decrypt files. Theoretically CTR mode is faster than CFB or CBC because of its individual operations on blocks. In my case CTR mode takes almost as long as CFB. How can ...
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151 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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177 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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234 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 to safely store the most recently used encryption password for subsequent reuse in an app?

Let's say I have a mobile app that can save photos inside password-protected AES-128 encrypted PDF files. For convenience, I want the user to be able to encrypt a file using the previously-used ...
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65 views

What CryptoPP APIs Output Round By Round Results for AES Encryption/Decryption?

I created a program using CryptoPP APIs to implement AES ECB mode with a 128 bit key for encryption/decryption of user input plaintext. I know that ECB is the least secure AES mode but it is ...
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175 views

AES-256 Decrypt a VHD File

I recently messed up with my McAfee Encrypted Laptop (2 Drives) and got MBR overwritten by Linux (Ubuntu). I used DETech CD on C: but after 2% it failed due to Bad Sector. Using a safety precaution ...
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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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664 views

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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270 views

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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717 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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157 views

Is my sending of encrypted information secure?

Please bear with me as I am not an expert in security. I have a server and a client. On the server I am encrypting a very secret message (using AES256-GCM to hide the information and protect it's ...
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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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180 views

Is it insecure to provide a hash of an AES password?

I have made some software that encrypts and decrypts files using AES. I was wondering if it is safe to write a hash of the password to the file so that the program can check if a password is correct. ...
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3k views

Using AES as a Stream Cipher

I need to send a lot of small messages that are usually between 128 bits and 256 bits long, and each message is encrypted with a separate 128 bit AES key. Therefore, to send each message with the key ...
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6k views

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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How does KEEPASS store images, videos and attached documents/items? [duplicate]

I have read quite a bit about KEEPASS and how it encrypts passwords. However, the more I read about it, the more I find how it generates and stores passwords - the methodology provided as well as the ...
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36 views

Could I use a TimeStamp also as IV?

For an academic application, I use AES-GCM to encrypt my frames between 2 parties. To enhance security, and reduce the possibility of replay, I'd like to use a TimeStamp in my frame exchanges. But, ...
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257 views

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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When to use HMAC alongside AES?

One of my clients wants to provide an URL to each of his customers to register in a system. This URL would contain a query string parameter with some data (e.g. code, email and name) from his clients ...
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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 ...
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559 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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112 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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308 views

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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2k views

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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Stacking Encryptions (Stream over Block)

I am reviewing the code for a product our team developed where credit card information is stored in a local database in the event of no internet connection and came across the encryption methods. The ...
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1answer
112 views

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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326 views

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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228 views

Is it possible to prevent an attacker from capturing my WI-FI handshake on WPA-2 AES?

For quite a while I've been experimentally hacking wireless routers by capturing handshakes and Decrypting them using oclHashcat on my computer. even the most complicated passwords won't take longer ...
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175 views

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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395 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 ...