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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How secure is AES-256-CBC with user provided password and initialization vector

From my understanding the IV is used as a previous block for the first block only. But since each block is used by the following this adds significant security is a IV is provided and not based on the ...
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Calculate time taken to break AES key

A 256 bit AES key is required to be broken using the brute force method on a 2GHz computer. How long would it take to break the key in the best case and in the worst case situations? Assume that 1000 ...
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Has there been a breach of AES?

Are there any known logical flaws of AES Cryptography? I understand that you can always break the encryption by brute-force or by having backdoors, but I have not come across any sources that show a ...
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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 ...
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Why would you need a salt for AES-CBS when IV is already randomly generated and stored with the encrypted data?

I was looking at this code and came across these comments which says encrypting without a salt is insecure. Why would it be insecure when you are already using a random IV for each value? I think the ...
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Using AesCryptoServiceProvider in C#, should using an incorrect IV mangle just the first block?

This question was also asked on StackOverflow, but with no answers, and I thought this may be a better exchange, since I have the same question. http://stackoverflow.com/questions/9331984/using-c-...
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Unseen.is encryption claims revisited with their proprietary, patented “xAES” algorithm

I had asked last year about the encryption claims by the web service called https://unseen.is. The very same service that had claims of "beyond army level encryption", "4096 bit keys" etc. This is the ...
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Javascript Diffie-Hellman and AES protocols

I am using the BigInteger Javascript library to create a symmetric key using Diffie-Hellman protocol. I want to create 128,160 or 192-bit keys. After some research, I have found out that I should use ...
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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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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 ...
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Is there any security gain / risk by adding additional padding (beyond what is required) when using AES-256 to encrypt very short strings?

I would like to encrypt some authentication tokens using AES 256 (not tied to this algorithm but it seems to be a reasonable choice). These messages are usually very short at 128-256 bits. I'm ...
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Salt usage for Spring security?

I use the Spring security for Java web applications and I have written an authentication provider which is working without salt and now I want to either add salt or alternatively use the built-in ...
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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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168 views

How secure is my software for file encryption with AES-256?

I'm working on a project to build software for file encryption with AES in Java, it's operation is quite simple, but I was wondering if it is really safe. The program prompts the user for a ...
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Is there a security risk using a Symmetric-key for both encryption and HMACing

I am proposing to use an AES key to encrypt some data to send to a third party and in a completely separate operation/flow use the same key to create a HMAC of a message to send to the same third ...
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311 views

Is ccrypt 'AES 256' file encryption fundamentally flawed

The unix/linux utility ccrypt claims to be a more secure replacement for the old unix cryypt. However it seems to me that it has a fundamental flaw. When you encrypt a file using ccrypt it uses the ...
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How to Conceal/Detect PGP Symmetric Algorithm Used

When Symmetrically encrypting a file, (not signing, not an asymmetric encryption question), is it possible to conceal the encryption algorithm used, or is it already concealed, but just showing on ...
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Using PBKDF2 with AES and SHA2

I use the following inputs to encrypt using AES: UserPassword (plain text) SecretKey RandomIV I use the following inputs to encrypt using SHA512: UserPassword (plain text) RandomSalt I'd ...
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question on hashing an aes-encrypted file

I am storing multiple sensitive data on a server that I do not own. The data is encrypted using aes-256 using cbc mode. The keys are only with me, and are stored securely. I am worried about the data ...
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How do cryptographic algorithms help hackers to bypass Antivirus software?

I was wondering how do hackers use cryptography for bypassing antivirus software. I don't have some deep understanding on how antivirus software works, but I know that every antivirus has base of ...
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Saving Personal Information (Name, Address, Phone, Email) in MySQL Database

I'm going to build a web app for people to sign up and pay for a membership. The transaction information will all be processed through Authorize.NET but we save the rest of the information (Name, ...
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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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Sending Encrypted Messages with Hybrid RSA, AES and HMAC SHA-256

Is this a Secure strategy for sending a large Encrypted Message using Hybrid RSA 2048, AES 256 and authenticated with HMAC SHA-256: Given the Alice already has Bob's RSA Public Key, Alice: ...
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Which block cipher should be used in TLS 1.2 (while keeping 1.3 in mind)?

I have been looking a bit at the various block ciphers for TLS. As everyone should (pipe dream) have migrated to TLS 1.2 by now it should be considered how to prepare for TLS 1.3, when it has been ...
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Why does Java allow AES-256 bit encryption on systems without JCE unlimited strength policies if using PBE?

It's fairly standard knowledge that due to the cryptography export controls, Oracle JRE ships with "limited" cryptographic strength enabled as listed in the JCA Documentation. For AES, the default max ...
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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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Extract AES key by comparing plaintext and encrypted data

Is there a kind of analysis which would enable me to get AES key which was used for encrypting arbitrary data while I have both original and encrypted version of data ? The problem is that the AES ...
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Why is 128bit AES considered very strong but 160bit SHA depreciated?

Why is 128bit AES considered very strong but 160bit SHA 'insufficiently secure'? Google/chrome/browsers seems to drop support for SHA1 SSL certificates. I assume it's more simple to calculate SHA than ...
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Is it safe to have the salt equal to IV?

If I'm using AES-256 CBC to encrypt, getting the 32 byte key using multiple iterations of the PBKDF2 function with a 16 byte salt, is it safe for me to let IV be equal to the salt? (Edit: The salt is ...
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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) ...
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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 ...
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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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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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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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Is it secure to use a part of the key as IV in AES?

I seen a lot of AES implementation samples wide spreaded over the Internet in almost every language I can recognize. There is one difference that I reflect to be repeated between all. Some of them ...
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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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Is splitting up an AES Key a problem?

I'm wondering if it would be a problem to split up a 256 bit AES-Key into two 16-Byte blocks and distribute it, to implement some kind of a four-eyes-principle (you need two persons to decrypt a ...
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Is symmetric encryption with one time pre-shared key secure?

Suppose I have a secure channel between client and server, with proper certificate validation etc (actually, ssh session). I want to establish a secure connection between my own application on a ...
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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 ...
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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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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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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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Confidentiality and integrity for web session

When the client authenticates with our service, he is issued an opaque "token". This token includes the information, that identifies the client and some other information about the client ("payload"). ...
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Question about AES-CBC IVs

I'm writing a Java program that encrypts strings with AES-CBC encryption. (Eventually I'm going to add steganography functions too). As you are well aware, CBC needs an IV in order to encrypt the ...
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Is it safe to reveal AES encrypted password?

Please correct me if any of my statement is incorrect. It is probably more good practice to not show any hint of the password. However, AES encrypted passwords by itself cannot be used to decrypt ...
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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 ...
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Is OpenSSL AES GCM standardized?

I have been reading about the perils of not going the pages of my own encrypt-then-mac implementation, because there so many things can go awry. So decided to use EVP_aes_256_gcm. But some questions ...
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LastPass One Time Recovery Passwords--How?

The LastPass password manager stores One Time Recovery Passwords locally in each browser you use the plugin with: http://helpdesk.lastpass.com/account-recovery/ My question is, how can you have more ...
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Key length and hash function in PBKDF2

On this page: http://www.ruby-doc.org/stdlib-2.0/libdoc/openssl/rdoc/OpenSSL/PKCS5.html they make a statement that strikes me as rather weird: Key Length Specifies the length in bytes of ...
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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 ...