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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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 ...
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Symmetric encryption involving load balancers - can't randomize key?

I'm working on encrypting a web application's cookie. Using symmetric AES/CBC, I encrypt the cookie data before writing it out, and then decrypt it when reading it back in - the standard stuff. The ...
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1k 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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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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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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122 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 ...
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61 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 ...
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92 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 ...
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318 views

Using Apple NSKeyedArchiver class without encryption to save score data locally

first of all I'm sorry for my bad English! I have a question about the security of NSKeyedArchiver, a subclass of NSCoder of Apple Foundation.framework ...
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62 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 ...
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3k views

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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220 views

Is knowing 'a' encrypted with 'b' and 'b' encrypted with 'a' a possible threat?

Excuse me for question name, but I couldn't find any other suitable title. I want to validate client connecting to the server. My algorithm looks like that: Clients sends his login - plaintext ...
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371 views

Can AES-256 encrypted data be changed?

I have a file that supposedly contains AES-256 encrypted data. The file was created using a proprietary program that claims to use AES-256. I have tested decrypting the file with an open source ...
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413 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 ...
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85 views

Saving passwords decryptable for later usage

I'm in a situation where I need to calculate a hash of the result of the password in plain text plus some random chars representing a session. The gained hash will be compared to another hash that is ...
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41 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 ...
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151 views

Have I crossed my t's and dotted my lower-case j's? (or, implementing AES, please help get some eyes on my code)

So, I used the crypto module in node.js to implement a secure key generator and encrypt/decrypt functions. Knowing that security's best friend is a spotlight on the implementation, I want to throw it ...
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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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100 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 ...
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331 views

Security of several files all using same password/key (7zip, AES256)

I'm working on a simple secure mirror for potentially untrusted services like Dropbox, Owncloud and so on. (Current code may be seen here: http://www.codeduce.com/extra/secure_mercurial) Currently ...
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119 views

How is the key obtained when I login via VPN?

So, I configure my VPN (let say which uses PPTP protocol), enter the server name, username and password. Then, I visit a website. Before that, my request is encrypted using AES with some key. That ...
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22 views

In TLS1.2 AES-GCM mode, what happened when input is not exactly the multiple of its block size?

I know that AES-GCM mode does not need padding, and its output are exactly the length of input data plus the tagging. But I am a little bit lost, as AES itself is block cipher, it could only operate ...
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70 views

Cracking Kingston DataTraveler vault privacy - is it possible?

I have Kingston DataTraveler vault privacy USB flash drive (DTVP/2GB). Here is tech specs. Flash drive has a 256-bit AES hardware based encryption. My flash has password protected and I do not know ...
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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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50 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 ...
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108 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 ...
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571 views

What is the advantage of using a symmetric cipher like AES to generate a keystream?

I see examples of AES (with a shared secret key) being used to encrypt shared secrets (e.g. nonce + counter) to produce a keystream against which the plaintext is XOR'ed to produce the ciphertext. ...
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73 views

Encrypting data in a load-balanced application - am I doing this right?

A web application I'm developing needs to store some sensitive data in a database. I need to be able to retrieve and use this data later on so hashing isn't enough. The web application might, at some ...
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646 views

Ways to keep AES encryption key safe.? [closed]

I am using AES encryption to secure some sensitive data. For that i have to provide a certain key for encrypting and decrypting. It's not safe to keep the key somewhere on the server. So instead of ...
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1k views

Using JTR to crack Skype Passwords

The scenario: coworker's Skype somehow lost his auto-fill password. He doesn't remember it anymore, and the account is hooked up to an email address that no longer exists. He's never purchased any ...
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3k views

How does PKCS#7 padding work with AES-256, CBC mode?

I'm a bit confused with AES-256, CBC, and how it works with padding (PKCS#7). Whenever I encrypt data of multiples of 16 bytes (the block size), extra 16 bytes are always padded at the end. For ...
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512 views

What AES mode does SQL Server 2012 use?

I looked at this link that shows how to encrypt a SQL column via a certificate (RSA??) and AES256. I created a dummy table (script at GitHub) intentionally using identical plain text (Credit Card = ...
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256 views

AES encrypt secret key with plaintext

We need to be able to retrieve password. Hashing is one-way, we can't do that. So we ended up using AES. We want to know if the following schema is safe or not. I am only familiar with modulo PK ...
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519 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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51 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 ...
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83 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 ...
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1answer
41 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 ...
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64 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 ...
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126 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 ...
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77 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 ...
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227 views

Can SHA-1 PRNG still create secure cipher keys?

I am concerned that a SHA-1 PRNG cannot produce an AES-256 cipher key with the expected 256 bits of security, or indeed any secure cipher key where over 165 bits of security are expected. The SHA-1 ...
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66 views

What key needs to be used to compute HMAC?

I use AES-128bit to encrypt files and I want to compute a HMAC for each one of the encrypted files to ensure their integrity. Can I use directly the AES KEY to compute HMAC or should I used a derived ...
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350 views

How to implement shamir's secret sharing algorithm using AES_ENCYRPT

I am using MySQL AES_ENCRYTP() and AES_DECRYPT() to store sensitive details in a database, and currently storing the key in a php file outside of the web root with read access only. The key file looks ...
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208 views

Should I run my password through Bcrypt before using it for encrypting a file with AES-256? [duplicate]

I need to encrypt a file with a password that can be memorized. So I was thinking about running the password through some rounds of Bcrypt before using it for AES encryption, so every time I want to ...
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202 views

Key distribution advice

I have been thinking for days about that problem! The application is based on a student system management. I am implementing database encryption on a column level and The encryption occurs at the ...
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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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35 views

PHP/Ajax Data transmission security

I'm learning about web security mechanisms. I have developed the following system in PHP and JavaScript: assuming that I have a page named: messages.php which is a real-time chat system. first when ...
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37 views

get encryption key from encrypted and decrypted data

I used encfs to encrypt some important files on my system , But sadly i forget the encryption key , i still have a version of some of the the encrypted files .so my question is : is there there a way ...
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98 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 ...