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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Encryption - RSA vs. AES

I have a question regarding encryption and whether to use symmetric or asymmetric encryption. The idea is to implement a form of data encryption in a variety of software. This data will be exchanged ...
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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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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
91 views

Effect of “decrypting” clear-text then “re-encrypting” it

I have a (unique) situation where I receive data that is a combination of encrypted (with AES-CBC) and clear-text blocks and I cannot tell which blocks are encrypted. I plan to decrypt all of the data,...
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1answer
95 views

Basic question regarding OpenSSL and AES-GCM

While researching how to encrypt private keys for SSH connections as securely as possible, I have run into the following very basic understanding problems (Note: I have used the newest stable release ...
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2answers
84 views

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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1answer
85 views

How safe is this “Multidimensional-Encryption method” (includes xAES, familiar from Unseen.is)?

I would like to ask about this encryption method that I found: USPTO patent and it is related to this question here: A service that claims beyond army level encryption Didn't see any updates on this ...
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2answers
95 views

How are the disk encryption keys protected when a laptop is locked?

If you were installing such operating system as Ubuntu, you would have seen an option to encrypt your home directory or the whole hard drive with an AES 256bit cipher. When your laptop is totally ...
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2answers
89 views

Which of AES modes are safer and faster for transferring data over the network?

I have using Crypto++ in Qt and use of AES Algorithm for encrypting files. I know about AES modes and their applications. I have use of StreamTransformation method for encrypting files in CBC and EAX ...
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1answer
63 views

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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60 views

Key-exchange over the network with more than two peers

Me and my team is developing a multiplayer videogame with a Client/Server-Topology. This secures the match from clients who have the intention to cheat because of server authority but still allows the ...
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1answer
60 views

How to use a different key and IV for encrypting a file with AES in C++?

I know how AES encryption works, and different modes (for example EAX, CBC, CCM, ...), and also about CipherBlock and StreamTransformationFilter methods and their implementation in C++. I am using ...
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118 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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1answer
90 views

Is using trim on a ssd with LVM LUKS safe?

I know that it can allow an attacker to know the filesystem and file size, but can it allow an attacker to decrypt any files?
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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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0answers
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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1answer
76 views

Firmware protection scheme

Edit: I have found a scheme that fits my limits (little memory, only AES is available): AES-CMAC described in RFC 4493 (just remember to use different key for encryption and MAC ;) . I am working ...
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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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1answer
29 views

Is it ok to append the nonce/iv to the ciphertext when using AES GCM?

I want to use AES GCM to encrypt data at rest. When retrieving the data, I want to make sure that the key is valid and the data has not been tempered with. Can I store the nonce/iv along with the ...
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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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1answer
69 views

Questions regarding AES 256

i have googled and searched quite alot but most things just state the same things but not answering my questions so hopefully you guys can help me out abit Story: i am looking at creating an ...
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2answers
101 views

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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1answer
58 views

How authentication tag is calculated in AES-GCM-256

I have a sample code,which encrypt and decrypt a string using AES-GCM-256. I am unable to understand,how authentication tag is being generated on encrypter side and how is that being used on ...
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2answers
166 views

store passwords as one-way-hash, or just use it as an AES key?

I want to store some data so the only one who'll be able to access it is the user itself. Here is my idea: when user registers, his password will be hashed in SHA256 (so it'll fit as an AES key), and ...
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1answer
64 views

OpenSSL brute-force attacking and file size

I use OpenSSL with aes-256-cbc to encrypt a 30 GB tar file containing a recent backup of my hard drive. Now suppose somebody wants to run a brute-force attack on this file, trying out all possible ...
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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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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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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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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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1answer
54 views

How can AES-CBC be used for LUKS encryption, when the ciphertext is not static?

In CBC mode of operation, ciphertext from previous block is used as IV in next block. How then can AES-CBC be used for disk encryption (LUKS), when the data on the disk (ie the ciphertext) keeps ...
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Why does IV not need to be secret in AES CBC encryption?

According to Wikipedia, the initialization vector (IV) does not have to be secret, when using the CBC mode of operation. Here is the schema of CBC encryption (also from Wikipedia): What if I ...
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1answer
55 views

Does use of fixed padding pattern compromise AES-ECB

I'm working on an application where AES-256-ECB has been specified. It has been asked that a fixed pattern is included at the end of the message to allow the decoding end to ensure the decryption has ...
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302 views

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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1answer
89 views

Store password ciphers using Powershell ? DPAPI/AES

Hi and sorry if it is in wrong place I am making a script that requires to have a lot of server's IP and their passwords stored into a file. I wanted to use Windows DPAPI, but as we can easily ...
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115 views

AES step by step

I can't seem to find an AES tutorial that starts from Unicode to Cipher text. All of the tutorials I found starts with 128 bit block already. Also, where do I start or what topics do I have to start ...
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Designing my own HSM using an Arduino

I am attempting to build from scratch something similar to Apple's Secure Enclave. What I've done is use an AES library for the Arduino to create a security appliance. A random crypto key and the ...
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2answers
162 views

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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1answer
374 views

I stored a copy of my KeePass database on a portable hard drive and I lost the drive. Should I worry about that?

I've been using KeePass for years, and I have a lot of accounts. I need to access them anywhere I work, so I store one copy of my database on a portable hard drive. The drive isn't encrypted. The ...
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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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7k views

How is WhatsApp sending end-to-end encrypted messages in push notifications?

WhatsApp implemented end-to-end encryption (whitepaper) in their latest update. How is it possible for WhatsApp to send push notifications with message contents to the Apple Push Notification service?...
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Diffence between AES-128 CMAC & AES-128 ECB/CBC?

Automotive standard for encryption use to talk about following algorithm AES-128 CMAC & AES-128 ECB/CBC. AES-128 CMAC use to provide Security service Authenticity AES-128 ECB & CBC used to ...
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1answer
112 views

Is webkey a reasonably secure authentication system?

I just created Webkey in the last couple days. It's built to do client-certificate auth without using the (in my opinion unusable) client-cert functionality built into browsers. It would allow single-...
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1answer
113 views

Why does this key get Base64 encoded prior to use?

I wish to have my server encrypt messages to clients who have each provided the server with an RSA public key, as well as having the clients authenticate their messages to the server using their ...
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1answer
70 views

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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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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2answers
858 views

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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1k views

Can I use SHA-512 hash as AES key?

I want to combine hashing and encryption for better security. So can I use a hash key generated from SHA-512 as a key in AES. For example, I have a password "secret", I calculate SHA-512 hash for it ...
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1answer
71 views

OpenSSL_encrypt returning an incorrect cyphertext?

I am trying to use the openssl_encrypt function in PHP, this is my code: <?php $message = hex2bin("00112233445566778899aabbccddeeff"); $key = hex2bin("000102030405060708090a0b0c0d0e0f"); $method =...
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2answers
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How does KEEPASS store images, videos and attached documents/items? [duplicate]

I have read quite a bit about KEEPASS and how it encrypts passwords. However, the more I read about it, the more I find how it generates and stores passwords - the methodology provided as well as the ...
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2answers
45 views

Could I use a TimeStamp also as IV?

For an academic application, I use AES-GCM to encrypt my frames between 2 parties. To enhance security, and reduce the possibility of replay, I'd like to use a TimeStamp in my frame exchanges. But, ...