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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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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Why does OpenSSL not include AES-256-GCM? [closed]

I'm trying to implement AES-256-GCM in Ruby. Ruby's OpenSSL wrapper library and aead library both clearly seem to believe that OpenSSL itself supports this. However, neither 0.9.8r (which I had ...
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1answer
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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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1answer
105 views

Securing the SOAP Messages

One of my clients wants to encrypt few sensitive information which will be transferred through webservices / SOAP. My client has the following suggestions: Encrypt the sensitive data with AES ...
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2k views

After How Much Data Encryption (AES-256) we should change key?

Considering AES-256 encryption, what is the maximum amount of data should be encrypted with one key? Does Block cipher modes/IV/counters also governs the limit? If say the maximum amount is 50GB, ...
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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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3answers
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AES CBC padding when the message length is a multiple of the block size

Assuming that a 32-byte plaintext is encrypted by AES 128 CBC - is it mandatory to add 16-byte padding, according to the different padding schemes?
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2answers
493 views

How to correctly implement AES in a backup application

I am writing a back-up application which should have the feature of encrypting the back-up. It must encrypt file data, paths and filenames. The application is being written in C# (.NET). Target is ...
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2answers
220 views

Remedy for not having filled the disk with random data?

Filling a large HDD with /dev/urandom prior to encryption can be extremely slow (even with netcat, multiple instances in parallel, etc) and for this reason I'm sure a lot of users skip this advice ...
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Is AES-GCM recommended for SSL?

I'm looking at turning on site-wide SSL for a website I manage, and I'm wondering what the best practices for SSL configuration. I'm not too worried about compatibility with old browsers and more ...
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1answer
1k views

Security of bcrypt/sha256 key used with AES to encrypt a file

I'm looking to encrypt files using secure hashing and encryption algorithms in Python. Having used bcrypt in the past, I decided to use it for my passphrase calculator, then pass the output through ...
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1answer
170 views

Need advice on Cryptography digital files project

I have to choose a topic for my end-of-year school project and I need some advice. I was thinking of implementing an online tutorial materials (digital files) project. I have been researching on ...
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339 views

Implications of having a service account in AD use RC4 rather than AES for Kerberos?

Bear with me, I know this is sloppy, but here is the back story: We have a partner that uses Jira and is using spnego with a custom auth back-end that expects certain group membership in the token. ...
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1answer
198 views

Implementation review - Independent key, admin side and user side

The admin of the website needs to read user data. So, if the key is derived from the user pass, then the admin has to know the user pass, not exactly a good idea. The following encryption scheme was ...
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2answers
5k views

openssl: recover key and IV by passphrase

A large amount of files were encrypted by openssl enc -aes-256-cbc -pass pass:MYPASSWORD Openssl should derive key+IV from passphrase. I'd like to know key+IV equivalent of that MYPASSWORD. Is ...
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2answers
3k views

Pitfalls of SSD encryption

Encrypting an SSD is a process that is sometimes warned should be done with caution. E.g. http://en.gentoo-wiki.com/wiki/DM-Crypt_with_LUKS mentions how the SSD may keep hidden space used for wear ...
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2answers
584 views

Filling the disk with random data prior to encryption?

Filling the disk with random data prior to encrypting it will supposedly make it harder for the attacker to perform any cryptanalysis. Most sources seem to state this is because it will be harder for ...
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2answers
21k views

Security comparsion of 3DES and AES

Which one is more secure and least possible to be broken through cryptanalysis AES or 3DES (no matter performance)? I need to use encryption for my projects to store and secure sensitive information ...
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1answer
211 views

Password protection of encryption and signature keys

I would like to store encrypted backup of text files on my computer. I'm developing a python script using Pycrypto to achieve that, based on this code to use the library. (current code) The basic ...
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WPA2 Enterprise AES encryption key size?

I have recently set up a RADIUS server with EAP for my wireless router, however, I have some questions about the key size and how WPA2 enterprise (AES) works in general. I have read that in ...
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4answers
371 views

RSA and encrypted authentication

Symmetric algorithms such as AES provides modes such as GCM which can be used for authenticated encryption. Assuming that I'm using RSA instead of AES, does it still make sense to add authentication ...
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1answer
191 views

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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3answers
730 views

AES using derived keys / IVs. Does it introduce a weakness?

I'm looking for an efficient way to encrypt multiple fields in a database with AES using a single global key, used throughout a large web application. Obviously in order to re-use this key, a unique ...
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2answers
569 views

User authentication + database encryption with same password

I'm working on a private project where I need to store a users financial data in a database. I'll encrypt this data using AES, and I'll be using scrypt to generate a AES ecnryption key from a more ...
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1answer
396 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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1answer
578 views

Android and AES side channel attacks

I am working on a project that will involve symmetric AES 128 bit encrypted communication between an Android application and a bluetooth device. Are there any public AES libraries available for ...
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How can I encrypt a file with .NET and have the same file size of the original file?

I'm using .NET and I've written an awesome routine (xD) that encrypts and decrypts a file using AES256 CBC. It works perfectly, but now they told me that the encrypted file must be of the same size of ...
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I don't see how “-salt” in the openssl command line tool enhances security at all

I do this to encrypt a single file: openssl aes-256-cbc -a -salt -in file.txt -out file.enc and then type in some regular plaintext password. I do not understand how -salt enhances the security of ...
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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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2answers
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Decryption on AES when the same key and IV are used

Let's say that I have three messages being encrypted by AES-128 with the same key and IV every time. Is it possible to decrypt the key being used? And more importantly, is it possible to decrypt the ...
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2answers
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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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1answer
591 views

How does Cipher Block Chaining relate to AES?

I was reading FIPS197 for a class (found here: http://csrc.nist.gov/publications/fips/fips197/fips-197.pdf ) trying to find some sort of specific relation between CBC and AES. I guess my problem is ...
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User data encryption/decryption in a database (PHP)

I was wondering which is the best way to encrypt and decrypt user data in a database, to make it much more secure as it is possible? I was reading about AES but I would like to know if is really the ...
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1answer
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Where is the salt on the OpenSSL AES encryption?

I'm interested in knowing how and where OpenSSL inserts the generated salt on an AES encrypted data. Why? Im encrypting data in Java classes and need to guarantee that I can use OpenSSL to decrypt ...
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2answers
366 views

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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3answers
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How secure is Intel SSD Encryption?

Are there any known flaws in the full disk encryption on Intel 520 series SSD drives? Specifically, it seems these drives generate an internal AES key automatically, even when no password is set. But ...
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1answer
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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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696 views

AES Key Generation Strategy/Algorithm For Offline System

Let say I have several application that aren't connected to any network, and I have one requirement that says each application could produce a token from an input that other application could validate ...
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Does AES-192 provide better encryption than AES-256?

this wikipedia article describing AES says: Related-key attacks can break AES-192 and AES-256 with complexities 2^176 and 2^99.5, respectively. Does this mean that AES-256 is actually a weaker ...
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1answer
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OpenSSL fails NIST AES-128-ECB test vectors?

I'm having trouble getting OpenSSL's ciphertext to match the NIST test vectors. Example : in "ecb_e_m.txt" from http://csrc.nist.gov/archive/aes/rijndael/rijndael-vals.zip, the first test is (in hex) ...
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4answers
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Asymmetric crypto: Decrypt own messages without having private key

I have built a messages system for my website. Users can send the admin messages which are stored in the DB after being AES-encrypted. I think that using asymmetric crypto (RSA through openssl) ...
2
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1answer
2k views

Kik | WhatsApp - Encrypted? iOS / Android Message encryption tips [closed]

Kik says that their client is using ssl etc. But it's kind of hard to tell if the messages is actually encrypted between the devices. What i can understand is that they don't got device-to-device ...
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2answers
173 views

Protecting passphrases within an application

First off, I'm not very familiar with encryption best-practices. My use-case is simple: I'm creating an application that will be reading encrypted documents and decrypting them dynamically to do some ...
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3answers
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Is multiple encryption a good idea?

I know that many encryption algorithms, while secure, have vulnerabilities. To reduce risks, would multiple encryption like this Blowfish_CbC ( Rc2_OFB ( AES128_CBC (myfilecontent))) be a good ...
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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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1answer
829 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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When using AES and CBC, is it necessary to keep the IV secret?

If I encrypt some data with a randomly generated Key and Initialization Vector, then store all three pieces of information in the same table row; is it necessary to encrypt the IV as well as the Key? ...
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3answers
935 views

Verify Login and Encrypt with PBKDF2

I'm writing a desktop application where I'm using PBKDF2 to generate an encryption key to AES-128 encrypt the config file. The config file contains a crypo-random key that's been used to encrypt the ...
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1answer
520 views

How secure is AES-128 for Zip files?

Say you have a cryptographically random 8 character long alphanumeric password (A-Z, a-z, 0-9) used to encrypt a ZIP file with AES-128. Can this program: ...
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Securing AES 128 encrypted ZIPs against brute force attacks

How long would it take to brute force decrypt an AES 128 encrypted zip file if the password is 8 characters long in the range of A-Z, a-z, 1-9? Does it make any difference if .NET's System.Random ...