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 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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17 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
58 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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81 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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27 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
123 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
56 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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35 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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38 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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89 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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20 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
49 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
36 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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2answers
262 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
49 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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1answer
94 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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2answers
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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
151 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
340 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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0answers
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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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2answers
6k 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 ...
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70 views

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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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 ...
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1answer
106 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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51 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
835 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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2answers
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
39 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
58 views

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
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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, ...
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Cryptography basics (in the context of AES256) [closed]

Bit of a noob question and a fair bit of Googling didn't help. I understand that the current encryption standard is AES256. A few questions 1) Is the point of this (and other encryption techniques) ...
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59 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 ...
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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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2answers
165 views

Is AES 128 encryption weak for very small payload size?

If I have a payload of e.g. 8 bits and I want to encrypt it using AES 128, I will need to add some random padding to make the plaintext 128 bits long. Does this padding affect the security of AES?
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3answers
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Will quantum computers render AES obsolete?

This is a spin off from: Use multiple computers for faster brute force Here's at least one source which says that quantum computers are on the way to being able to break RSA in the not too distant ...
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3answers
4k views

Use multiple computers for faster brute force [duplicate]

I've watched Mr. Robot lately and can't stop thinking why it was so hard to decrypt files encrypted using AES encryption with a 256-bit key. Let us say the only method to find the key is through brute ...
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2answers
55 views

Are any inherently insecure AES-CBC keys or key-IV combos known for properly generated random values?

This is mostly a theoretical question. I am using AES128 CBC to encrypt small files. Both my keys and my IVs are randomly generated per file using iOS's secure random value generation ...
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1answer
124 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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1answer
60 views

How to make a good choice between Symmetric and Asymmetric [closed]

Here and there and read a lot of articles and blog posts titled "Difference Between Symmetric Cryptography and Asymmetric Cryptography". But inside of them they are answered "What is Symmetric ...
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1answer
82 views

FileVault 2 FDE and BoxCryptor are safe to use together or they have conficts?

Assuming that someone has a Mac and uses FileVault 2 FDE (256-bit AES key) and uses the BoxCryptor (256-bit AES key) for the clouds like Dropbox/GDrive/etc and or some other folders. FileVault 2 uses ...
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1answer
46 views

How is hash used with AEAD-based ciphers in TLS? [duplicate]

Look at this cipher: ECDHE-RSA-AES128-GCM-SHA256 TLSv1.2 Kx=ECDH Au=RSA Enc=AESGCM(128) Mac=AEAD It uses AES-GCM for encryption and data origin authentication (according to RFC-5288), so no ...
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8answers
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Why can't the FBI read the key embedded in the iPhone's secure chip/ROM directly from hardware (silicon)?

As far as I understand, the 4 digit passcode is combined (in some fashion) with a key stored in secure read only memory (e.g. secure enclave chip or similar), where it is directly embedded into ...
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Is cryptsetup luksFormat -y --cipher aes-xts-plain --key-size 512 /dev/sdax a insecure setup for luks [duplicate]

Is cryptsetup luksFormat -y --cipher aes-xts-plain --key-size 512 /dev/sdax insecure. If so why and what setup would be good for keeping corporate information safe?
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1answer
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Stateless AEAD (AES-GCM) based tokens

I want to generate secure data tokens which can be shared with the client for uses like password reset, etc. which involves low storage overhead at server end. Ideally I am interested only in managing ...
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77 views

OpenSSL key derivation

I'm trying to manually decrypt DTLS packets sent by OpenSSL. The cipher suite used between the server and the client is TLS_RSA_WITH_AES_256_CBC_SHA256 and my understanding is that the IV used by ...
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2answers
120 views

Length of AES “plain text” when decrypted with wrong key

If I encrypt a text X using key A with the AES algorithms, and then decrypt the result using key B, would the obtained plain text Y length be the same as X's? If the answer is no, is there any ...
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1answer
83 views

MySQL AES_ENCRYPT Logs Output

Need: I need to be able to store AES encrypted user data (journal entries) in my database and those entries need to be plain-text searchable. Issue: MySQL outputs queries to its logs in plain text. ...
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About the AES algorithm key and ciphertext

I have the two following questions about the AES algorithm: A- Does the key need to follow any specific pattern apart from length or can it be a completely random string? So, if I select 16 random ...