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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Is is possible to shuffle an AES ciphertext without owning the key for it?

I would like to know if it is mathematically feasible to change an AES(CBC) ciphertext and IV without owning the key, so that the ciphertext would look totally different while still decrypting to the ...
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2answers
91 views

How secure is aes-256-cbc with a 40 char password

I'm using this command from this article to encrypt a file: openssl enc -aes-256-cbc -in /etc/services -out services.dat -k MYPASSWORD If MYPASSWORD is 40 characters in length, roughly how long ...
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1answer
108 views

Does using the same secret key for AES-256-CBC and HMAC-SHA512 in Encrypt-then-MAC potentially compromise the key?

Suppose I use a key (and IV) to encrypt a piece of binary data with AES-256-CBC to produce the corresponding encrypted data. Suppose I then throw this encrypted data into HMAC-SHA512 using the same ...
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1answer
195 views

How to wipe disks before encryption with dm-crypt if CBC or XTS is used internally?

First, please forgive me if I'm posting this question to the wrong community. Feel free to migrate this post to the right community if I was wrong. I'm quite new to whole disk encryption (but not ...
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1answer
187 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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1answer
2k 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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1answer
100 views

How to protect data at rest in a php application?

I was wondering which is the best way to secure data at rest (encrypt / decrypt) in a php application ( eq: stored in a database ) using AES ? Where is the best way to store the keys ?
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1answer
311 views

is encrypted body http secure

I'm working on an embedded project that needs to communicate with a server. Both the server and the device have an AES key pre-installed. I have a network device that provides http services but not ...
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1answer
89 views

How long does it take to brute force a 7 character long password taken from 16 character set

A database file is encrypted with 256bits AES and the key is the first 7 characters (from the character set 0-9, a - f, all small letter) of MD5 hash . This implies 2^28 bits (268,435,456) possible ...
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0answers
51 views

Why would I use at-rest encryption over a DB's key-based encryption?

Goal I want to store encrypted data in a database. Constraints Application-level encryption (encrypting before sending to the DB) is not a reasonable option for my use case. The DB providers I'm ...
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0answers
103 views

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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0answers
1k views

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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0answers
81 views

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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0answers
52 views

Security implications of providing an encryption/decryption oracle

I need to provide a service that acts as a symetric encryption/decryption blackbox : the box get a secret key k users send datas d, and get ciphertext c = Encrypt(d,k) users send ciphertext c, and ...
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135 views

Hiding symmetric key inside encrypted data

My server generates an AES encrypted file which when downloaded acts as an input for an application. So, should I hardcode the symmetric key inside the application or should I randomly generate the ...
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0answers
196 views

How is Tresorit client-side encryption key stored and managed?

I am using Tresorit on Mac OS X and iPhone. When I am using it there is always applied client-side encryption before posting the file to cloud. The key used for encryption is AES-256 and CFB mode of ...
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0answers
47 views

CCM instead of key wrap

Is there any instance of NIST or other encryption standards using AES-CCM to encrypt/authenticate key data? I would like to use CCM over a keywrap function, but cannot find any precedent for this in ...
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0answers
40 views

AES256 key exchange

I'm trying to get a secure way of exchanging keys between my client application and the server. The goal is to encrypt all XML messages with AES256. These XML's will be transferred to the server ...
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0answers
21 views

Authentication tag lengths of AES-CCM in TLS

I'm catching up on understanding some of the new cipher suites that are appearing in TLSv1.2 and will be making an appearance in 1.3. While looking through AES-CCM, I discovered that it offers a ...
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0answers
85 views

How to decrypt the my 1Password Vault without using the 1Password App?

I would like to know, how someone can decrypt his 1Password Vault without using the 1Password app. It should be feasible. Right? In a nutshel, My Master Password is the only "AES key" that my logins/...
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0answers
56 views

AES keyfile size

I would like to encrypt files using a key file instead of a password. What I would do is: 1) Generate X random bits using openssl rand X > mykey 2) openssl enc -aes-256-cbc -in secretfile -out ...
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0answers
89 views

OpenSSL is not giving correct result for encryption and decryption for FIPS test vector for AES -CFB1

I am running FIPS test vectors against AES-CFB. I am getting correct results for aes-cfb128 and aes-cfb8 but getting wrong results for aes-cfb1. The values being used by me for aes-cfb1 tests are: ...
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0answers
98 views

How can I use session salt for encrypting data using AES in CTR mode?

I have to implement a crypto-plugin in Java. The approach followed is conceptually similar to that used for SRTP. The algorithm used for data confidentiality is AES in CTR mode (I'm following a ...
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0answers
40 views

Are there “standard” formats for storing GCM output?

The openssl enc -aes-256-gcm command is broken, because it can't decrypt its own output, otherwise I would look to that as a format. In order to decrypt a file, code needs to be able to separate the ...
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43 views

AES and message properties

An active attacker changes the ciphertext which was made using the AES cipher algorithm. Which message properties are preserved even though that change was made. Choose one of the below: 1) Integrity ...
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122 views

Why do we need salt and RFC in generating AES encrypted message

I'm not very familiar with encryption and new to this, I'm just learning it right now by code review of one of the class we have in an application to encrypt a password using AES. Would anyone explain ...
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0answers
306 views

Is it safe to store the AES passphrase encrypted with the resulting AES key?

I found out that an encryption tool encrypts and stores the passphrase entered by the user and used to generate the AES key in addition of the encrypted payload. Pseudocode: key = md5(passphrase) iv ...
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0answers
264 views

Gladman's file encryption library = AES in counter mode with HMAC-SHA1 authentication?

I would like to use Gladman's algorithm to create AES encrypted data in JavaScript. I use the Crypto-JS library, but its performance is horrible. PBKDF2 is terribly slow, so I switched to another ...
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152 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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0answers
117 views

Security of an IoT network using AES (LoRaWAN)

I am studying the security of LoRaWAN. Here is a simplified architecture of the network: As you can see, there are two keys: one for the network security (no mitm, no modificatiof the messages). ...
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0answers
70 views

How could I encrypt an SD card to store data on it?

I have some data I'd like to carry with me in an encrypted form onto an SD card, so I (and only I) can access it easily from any OS (or at least Windows, OSX and Ubuntu). My idea was like: Two ...
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49 views

Choosing Key and IV in AES-256

I am working on a real-life project for a firm. I have to encrypt data using AES 256 as per specification. I want to know how are the key and IV are really chosen in real world projects. /dev/urandom ...
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28 views

AES256 nopadding vs PKCS7Padding

I was looking over AES Crypt's Java lib which seems like a secure AES encryption software and I noticed that they are using nopadding. Can somebody explain to me what the benefit of using nopadding as ...
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0answers
47 views

Create a TLS Application Data Message for AES-GCM

I was wondering if anyone could help me with structuring a TLS Application Data message for AES-GCM. I don't know how the IV, CipherText, Additional Data, and Tag fit together in a message. Thanks.
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30 views

Clarification of RSA Key Exchange (TLS 1.2) and AES for On-Going Message Excahnge

I'm trying to understand the full flow of key exchanges for secure communications. As a potentially incorrect premise, I am under the impression that RSA is a good asymmetric technique for ...
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28 views

when/how does an encrypted volume .dmg change to reflect the file system it stores

I'm trying to verify that storing a .dmg file stays encrypted while only the mounted file system is unencrypted (see here). My thought was to create a .dmg containing a text file, make a copy of the ....
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41 views

Creating iv parameter in AES encryption

The algorithm that I thought for creating aes key and iv is: Get two values from a certain elliptic curve point that agreed before by using asymetric encryption.(x,y) Aes.Key <- HASH(x) (string)...
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72 views

best operation mode for Rijndael-256 in PHP

so my question is about the operation mode. In another thread I heard that ECB is bad which makes sense when I read about it, so I wanna change some things at my Crypto to make it better and wanted to ...
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187 views

Cryptographic Testing

Given an algorithm (say, AES), how to create/generate test vectors? I have tried using the NIST test vectors for AES and found it to be working fine with a package of "chilkat". Suppose, for a ...
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0answers
80 views

Is it possible to encrypt Word Docs with something other than default?

AES 128-bit advanced encryption is fairly simple to break and was wondering if there was any way to use a more secure one? And if so - any suggestions?
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502 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 ...