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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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 ...
0
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1answer
35 views

Can I modify a ciphertext created in AES with OFB mode?

Suppose a service uses AES to encrypt Cookies, of the form user=username+padding,tmstmp=timestamp where tmstmp is the expiration time and +padding is a series of zeroes to make the total length be ...
0
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0answers
20 views

Security implications of an “obsolete” cipher as indicated by Chrome [duplicate]

I guess this has been asked before, but what are the security implications of the below message? I've seen ciphers such as AES_128_GCM being labeled as "modern". Is this mitigated server side (load ...
1
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1answer
81 views

why don't we measure the strength of crypto against the cost it would take to crack it? [closed]

I hear all the time how many hours it would take to break a certain type of encryption. I think this may be the wrong metric to look at ever since scaling became an easy to implement solution. Sure ...
0
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1answer
74 views

Why does initial encryption take so long? [closed]

I am encrypting my new 1 TB drive using VeraCrypt and AES encryption. It estimates 9+ hours just for the outer volume to be encrypted. I assume the inner volume will take just as long. Why does this ...
60
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2answers
7k views

Why has the NSA had a hand in deciding on encryption standards?

The NSA has had a large hand in the design of at least two significant encryption standards: the Digital Encryption Standard, and its successor, the Advanced Encryption Standard. Because of their ...
2
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1answer
65 views

Security risks of symmetric encryption with compression for database data

I would like to compress data before encrypting and storing it in a MySQL database to reduce especially bandwith requirements. In the future, the DB may be accessible via a web interface. Various ...
3
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1answer
170 views

Strange Finished message in TLS

I've tried to understand the content of the Finished message of TLS. I'm using WireShark to capture the traffic between my browser and the internet. I noticed a "strangeness" when the chosen ...
2
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1answer
137 views

is it true that AES-128 and AES-256 are Quantum resistant?

is it true that with the rise of quantum computers, which is pretty close these days, AES 128 and 256 are resistant? while PGP and RSA are not?
-2
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1answer
102 views

how does AES encryption's algorithm actually work?

can anyone actually explain in simple and plain terms, how does AES encryption algorithm works? i can guess that the only significant distinction between AES-128 and AES-256 is their key size and NOT ...
1
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1answer
65 views

AES_GCM and TLS sequence number

Am I right about that AEAD encryption/decryption uses a TLS sequence number twice, first time in the nonce and a second in additional data? And why did they make the TLS 1.2 sequence number 2 times ...
31
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2answers
56k views

Security comparsion of 3DES and AES

Which one is more secure and least possible to be broken through cryptanalysis AES or 3DES (no matter performance)? I need to use encryption for my projects to store and secure sensitive information ...
3
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1answer
98 views

Is rounds in a cryptography algorithm same as iterating the algorithm?

In a cryptography algorithm such as AES or DES, does the number of rounds mean same as iterating the algorithm? Example: c= "plaintext"; for(int i=0;i<5; i++) { c = AES(c , "key"); } Where c ...
4
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2answers
210 views

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 ...
21
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3answers
15k 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); ...
2
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0answers
61 views

Store encrypted data and encryption key on different MongoDB servers? [closed]

In my Rails app users are submitting sensitive username/password combinations to their webshop systems so my app can interact with them. I need to enforce a high data-at-rest security for these data. ...
1
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3answers
114 views

Symmetric encryption involving load balancers - can't randomize key?

I'm working on encrypting a web application's cookie. Using symmetric AES/CBC, I encrypt the cookie data before writing it out, and then decrypt it when reading it back in - the standard stuff. The ...
4
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1answer
144 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 ...
7
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1answer
161 views

AES-ECB chosen plaintext attack with long secret

I'm having some trouble understanding the methodology for a crypto exercise I'm doing. The goal of the exercise is to recover an encrypted secret string through a chosen key attack on AES in ECB mode. ...
2
votes
2answers
101 views

Best hash for indexing and searching encrypted data

I would like to be able to do database look-ups on a set of data based on one of the encrypted fields. My understanding of the best practice for accomplishing this is to store a hash of the data I ...
1
vote
1answer
38 views

Hashing Based Encryption

Let's say you take a 256 bit key and never use it to encrypt anything. You receive a message with a 16 character unique randomly generated salt pre-pended. You salt your key with the 16 character ...
3
votes
1answer
135 views

IV Reverse AES-256-CBC PKCS#7

I'm a freshmen in cryptography and want to know more about IV reversing. There's a lot of posts about finding the passphrase with a new IV. But what about the other situation? This is for educational ...
7
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3answers
997 views

Are temporary files an issue when opening and editing an encrypted 7z file?

I am new to security and encryption. I want to store important information like passwords and pin codes so I don't forget them. So far I have been using LastPass but I would prefer a solution I ...
0
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0answers
56 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 ...
2
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1answer
167 views

AES encryption between Java and Ruby: what is the default mode and padding for AES in Java?

I'm writing a ruby app that needs to create some encryption that our java app needs to be able to decrypt. For this I have done some research, and I have this Java code now: Cipher cipher = ...
0
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2answers
96 views

Standard AES vs additional parameters with Rijndael - what is more secure?

I know that Rijndael and AES are pretty similar and AES is just a subset of Rijndael, and I have read that Rijndael can have 256 bit blocks while AES has "only" 128 bit blocks. The problem is that I ...
4
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1answer
1k views

What difference between AES_128_GCM and AES_128 and AES_128_CBC ciphers?

I encountered AES_128_GCM cipher, tried to find it in specifications of TLS1.2 and nothing, any mention. Could some one explain the difference between AES_128, documented AES_128_CBC and this new kid ...
13
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1answer
12k views

Where is the salt on the OpenSSL AES encryption?

I'm interested in knowing how and where OpenSSL inserts the generated salt on an AES encrypted data. Why? Im encrypting data in Java classes and need to guarantee that I can use OpenSSL to decrypt ...
2
votes
1answer
107 views

MasterSecret expansion into keys

I'm trying to deeply understand the steps during a TLS handshake. I've read this answer (which is btw pretty complete), but I stil got a question about the utilisation of the MasterSecret, in the ...
1
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1answer
91 views

Is it safe to use the SHA1 checksum of a password as a key for SHA-1?

I have an authentication system, where the passwords are stored with bcrypt hash (node passport module). My server generates a random key (128bytes) at startup. Whenever a user logs in, the server ...
3
votes
2answers
69 views

Can EAP-TLS and AES256 encryption be used together?

What is the difference between EAP-TLS and AES 256 encryption? Can they be used together? Or are they separate protocols?
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0answers
199 views

How to unwrap exported key from safenet HSM? [closed]

I am trying to write a software that will inject keys generated inside an HSM into a POS device, in the same way as described here I'm using the Safenet emulator(software-mode) + the wrap/unwrap ...
-1
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1answer
100 views

How can I secure encryption keys in the code? [duplicate]

I have files on the server that is encrypted with AES. I am developing iOS and Android apps to decrypt and process those files in the phone or tablet. To decrypt files on the client apps, I have to ...
2
votes
2answers
333 views

Practical steps for encrypting an encryption key for data stored in MySQL

So I'm working on my first project where user data is stored as encrypted using the user's password as (part of) the key. I have read many similar things about best practices, but the details seems to ...
1
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1answer
69 views

Should I worry about padding oracle?

I have a PHP webapp which encrypts (by AES192-CBC) messages with a random key and a random IV. Everywhere people are saying how amazing are GCM, EAX and authenticated modes (does currently exist safe ...
4
votes
2answers
129 views

Securely store session data in cookies

I'm trying to create a stateless application server architecture and I would like to store session data in cookies. All pages using the session would be served over HTTPS. I was planning on using ...
0
votes
1answer
107 views

What is the “segment size” when using Cipher FeedBack (CFB) chaining mode?

When using CFB chaining mode with AES, I see instructions that the "plaintext length (in bytes) must be a multiple of segment_size/8" (also mentioned here). What does that mean?
1
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3answers
153 views

What benefit to use different encryption key (passphrase) for different customers?

When we store confidential information in our database, we encrypt it using AES. In addition, when customers install our product, they protect their machines using a firewall. Should we use different ...
2
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2answers
85 views

Authenticated encryption (Symmetric encryption) for .NET applications [closed]

Is there an implementation of Authenticated encryption for .NET applications? The AES API from .NET does not include mode such as GCM. In the documentation, I can only see insecure modes (ECB, CBC, ...
2
votes
1answer
123 views

AES-256 Decrypt a VHD File

I recently messed up with my McAfee Encrypted Laptop (2 Drives) and got MBR overwritten by Linux (Ubuntu). I used DETech CD on C: but after 2% it failed due to Bad Sector. Using a safety precaution ...
1
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1answer
128 views

Secure Software Architecture

I am designing a software architecture and i need some suggestion and clarification on few issues. This will be a server side RESTfull API for accessing data and multiple mobile/desktop client to ...
4
votes
2answers
112 views

What encryption and signature systems (don't?) allow for plausible deniability of the OP's key being used?

I need to prevent Mallory from blindly matching encryption and signing keys to messages Hypothetical scenario: A user creates a public key An encrypted or signed payload exists. With only public ...
4
votes
1answer
268 views

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: ...
2
votes
2answers
130 views

Clarification about IV in PBKDF2 to generate encryption key

I've realized that the following implementation isn't truly safe: $pb = pbkdf2('sha256', $_POST['pass'], "enc_salt", 100, 100); $d = openssl_decrypt ($data['container'],'aes-192-cbc', $pb, true, ...
8
votes
4answers
2k views

Is this RSA/AES combination good?

The team of developers I am part of is trying to develop a safe way to exchange sensitive data between a server and mobile devices. We have come up with the following algorithm: Device generates ...
2
votes
1answer
85 views

Is a Fernet token's timestamp a security risk?

A Fernet token has the following format: Version ‖ Timestamp ‖ IV ‖ Ciphertext ‖ HMAC As the above shows, the timestamp is not part of the ciphertext, so anyone can read the time the token was ...
3
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1answer
83 views

What is the output length of CBC with zero input?

Given this formula for CBC encryption from 6.2 The Cipher Block Chaining Mode what is the output length of CBC if plaintext P is of length 0?
3
votes
2answers
165 views

Is it possible to construct a specific AES collision?

Suppose I have a plaintext message P, and I encrypt it using key K to get ciphertext C. It's trivial to find a different plaintext message P' and a key K' so that the encryption results in C: just ...
1
vote
1answer
50 views

Detect if AES and hmac keys are invalid

I have a server which has a configured value of AES and HMAC key. The client also should have the same keys. When the client sends a request, the server interprets this request and reads the message. ...
7
votes
3answers
2k views

Is AES 256 secure enough for putting Backups to AWS or Dropbox?

How long would it take with current hardware to hack an Disk Image which was encrypted with AES 256? I ask because i want to backup personal files (contracts, tax-things, code, keys, private ...