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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Designing a cryptographic file-sharing protocol

As a learning project, I am trying to implement a secure way to share files with a friend over dropbox. (I am not looking for existing software, I am doing this in order to learn how to do this ...
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2answers
209 views

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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2answers
6k views

Recommended options for LUKS (cryptsetup)

I'm looking for recommended options for cryptsetup to create fully encrypted SSD (SanDisk SSD U100 128GB), which achive: Timing O_DIRECT disk reads: 1476 MB in 3.00 seconds = 491.81 MB/sec Timing ...
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1answer
572 views

When do I use NIST AES key wrapping?

Key Wrap constructions are a class of symmetric encryption algorithms designed to encapsulate (encrypt) cryptographic key material. The Key Wrap algorithms are intended for applications such as (a) ...
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1answer
396 views

How to encrypt by AES-Twofish-Serpent

I was wondering how to encrypt by doing a AES-Twofish-Serpent encryption. Does this mean I encrypt in AES first then after that in Twofish, and after that in Serpent (three separate encryptions). ...
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372 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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1answer
678 views

What's the hash for in ECDHE-RSA-AES-GCM-SHA?

Presumably the SHA is for deriving the AES key from the shared secret. Where else is the hash used? ECDH just does ECC (no hashing). RSA does masking and padding but this doesn't involve the ...
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3answers
650 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 ...
2
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1answer
95 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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3answers
2k views

How can I securely convert a “string” password to a key used in AES?

I'm writing some software where I have to encrypt all files that are written to a specific folder using AES. There is one password/key that is configured somewhere, that is always used. I don't want ...
8
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5answers
3k views

SSL/TLS - Distinction between self-signed cert and self-signed CA, and other questions?

I have a small personal website which I wish to serve securely over HTTPS. At the moment I do not wish to use a third party CA to sign my certs. I was reading this document on generating a self-signed ...
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1answer
320 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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2answers
115 views

Serving data from an encrypted database over an encrypted connection

There is encrypted data in the database (asymmetric FYI). It is to be viewed as decrypted on the website. The data can be sent to the client as encrypted to be decrypted on the client's computer, or ...
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1answer
299 views

Encrypton method that would encrypt alphanumeric data to alphanumeric data [closed]

I need efficient way(possibly as strong as AES or AES itself) to enrypt (only) aplhanumeric data and get out only alphanumeric data, using some known library (i don't want and intend to implement AES ...
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3answers
1k views

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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3answers
783 views

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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3answers
3k views

Can someone explain a little better what exactly is accomplished by generation of DH parameters?

I'm setting up a node.js server: https.createServer({ ... ciphers: 'ECDHE-RSA-AES128-SHA256:AES128-GCM-SHA256:RC4:HIGH:!MD5:!aNULL:!EDH', honorCipherOrder: true }, app).listen(443); ...
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1answer
3k views

Why does AES encryption take more time than decryption?

While I was studying the time consumed by some methods I found that encryption take more time than decryption. Is this right? I am using AES (the same steps will be taken during the enc and dec)
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2answers
5k views

Key size difference between AES and RSA

Can I say that 128 bit using AES provide more security than 1024 using RSA?
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1answer
639 views

Why can't a AES256-encrypted file be decrypted on machine other than the one it was encrypted? [closed]

I encrypted a file on my mac using openssl openssl aes-256-cbc -a -salt -in one.jpg -out two.jpg now if I try to decrypt it like that: openssl aes-256-cbc -a -d -salt -in two.jpg -out one.jpg on ...
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2answers
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 ...
2
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2answers
721 views

Login system using authenticated encryption without storing user password

I'm not a security expert, so I might be asking a silly question, but let me describe what I am thinking about. First, I know that a lot of web sites store hashed/encrypted passwords which could be ...
2
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1answer
80 views

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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1answer
210 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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2answers
181 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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1answer
333 views

Which is more secure, AES or Rijndael? [closed]

Which algorithm is generally considered to be more secure, and is AES-192/AES-256 still considered to be secure? After reading this it's lead me to belive that the Rijndael algorithm would be a more ...
2
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1answer
292 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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1answer
664 views

Cascading Encryption Algorithm using mcrypt or GnuGP

I'm trying to a cascading cipher encryption algorithm to encrypt a textfile via mcrypt. I'm essentially trying to emulate the behavior of TrueCrypt, where it can cascade two or three different cipher ...
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1answer
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 ...
5
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2answers
3k views

Encrypting using AES 256, do I need IV? [duplicate]

I'm looking into encrypting with AES using a 256bit key, and I notice that a number of methods in various languages, for instance http://php.net/manual/en/function.openssl-encrypt.php, and I notice ...
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1answer
3k views

Different performance of openssl speed on the same hardware with AES 256 (EVP and non EVP API)

If I run openssl 1.0.1e like this : $ ./openssl speed aes-256-cbc (i.e without EVP API) Doing aes-256 cbc for 3s on 16 size blocks: 14388425 aes-256 cbc's in 3.00s Doing aes-256 cbc for 3s on 64 size ...
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1answer
226 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 ...
2
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1answer
515 views

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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6answers
568 views

Is leaking the hash of your encryption key a security risk?

I've been trying to design a simple archive format, that allows me to just bundle a bunch of encrypted files together. The idea, I currently have is to embed not the encryption key but a truncated ...
3
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4answers
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RSA maximum bytes to encrypt, comparison to AES in terms of security?

What is the maximum number of bytes for encrypting a plaintext message using RSA that is reasonably secure and also efficient and would AES be better for the same size in bytes? The encryption doesn't ...
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2answers
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Questions to hybrid encryption. RSA with AES

I want to use a hybrid encryption in my application, so after reading a lot of lines I ended with this implemantation, please critizie it ;) (I want to stick to .Net) byte[] aesKey = ...
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1answer
154 views

What mode of operation is secure for block ciphers?

as RC4 is not secure and AES-CBC is same thing the only solution is using EAX mode for AES. but why mozilla NSS don't support EAX mod ? is there any secure EAX implementation ? and why wikipedia says ...
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2answers
401 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. ...
2
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2answers
2k views

Where do I securely store application-specific symmetric key?

I am writing an application App1. This application uses SQLite database and I plan to encrypt it using AES256. For symmetric encryption I need a key, which I need to store somewhere. From a similar ...
2
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1answer
922 views

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). ...
5
votes
2answers
379 views

How less secure is an encryption if we know something about the original data?

I have a number of files encrypted with a key derived from a password. In line with standard practice, I use a random salt and password and do many PBKDF2 iterations to obtain an encryption key and ...
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1answer
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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2answers
936 views

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 ...
3
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1answer
914 views

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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480 views

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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1answer
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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2answers
218 views

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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1answer
524 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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2answers
3k views

How X509 Certificates are used for Encryption

I have small doubt regarding the process of X509. I am aware of OpenPGP Encryption/Decryption, where we generate the public key and private key. We can share the public key to vendors and they can ...
0
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1answer
257 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 ...