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.

learn more… | top users | synonyms

0
votes
1answer
166 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 ...
1
vote
1answer
75 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 ...
5
votes
2answers
222 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
155 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?
0
votes
3answers
180 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
votes
2answers
112 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, ...
3
votes
1answer
209 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
vote
1answer
161 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 ...
5
votes
2answers
155 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
366 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
189 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, $...
2
votes
1answer
114 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 made....
3
votes
1answer
104 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
295 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
70 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
4k 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 ...
2
votes
1answer
621 views

How to implement encrytion/decryption system using IV between mobile app and web service

In my app we are going to send encrypted data to the web service. I am using the following code to encrypt and decrypt the data - public class DecEn { private static final String password = "test"...
2
votes
1answer
200 views

Is it insecure to provide a hash of an AES password?

I have made some software that encrypts and decrypts files using AES. I was wondering if it is safe to write a hash of the password to the file so that the program can check if a password is correct. ...
2
votes
0answers
90 views

A simple HMAC question

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 ...
1
vote
1answer
915 views

How to prepare FATCA data transmission files with open source tools [closed]

Here is the context: to transmit FATCA data to US IRS service the IDES protocol defines the following steps sign the XML Payload.xml file with enveloping signature, SHA-256 with RSA private key, as ...
1
vote
1answer
108 views

Why FATCA IDES “protocol” does not use RSA encrytion directly on Zip archive ?

Here is the context: to transmit FATCA data to US IRS service the IDES protocol defines the following steps sign the XML Payload.xml file with enveloping signature, SHA-256 with RSA private key, as ...
4
votes
2answers
805 views

How do cryptographic algorithms help hackers to bypass Antivirus software?

I was wondering how do hackers use cryptography for bypassing antivirus software. I don't have some deep understanding on how antivirus software works, but I know that every antivirus has base of ...
2
votes
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 ...
2
votes
1answer
123 views

Aes encryption algorithm life time [closed]

How many years from now will we stop using aes encryption algorithm, as of now aes seems to be virtually immune to brute force attacks and not showing any weaknesses, will quantum or optical computing ...
0
votes
1answer
129 views

Is it secure to not expire keys in symmetric encryption?

Note that this question describe hypothetical case, that is never meant to be used in real world. Server communicates with clients with message structure: client_id, initialization_vector, encrypted ...
-3
votes
2answers
119 views

AES algorithm encryption time

What is the time taken by an AES Encryption algorithm, with a key of 128 bits, operating on a normal computer (say with Intel i7) and what will be the impact be on the time if I wish to use a 256 bit ...
0
votes
1answer
250 views

Which one will give me the best VPN security when choosing Encryption algorithm in pfsense?

I want to setup an VPN server in pfsense and I can choose a lot of Encryption algorithm types ,alot!! What I have read is that the AES 256 (512 is not an option) is the best. Well even then there are ...
6
votes
3answers
8k views

Encrypting using AES-256, can I use 256 bits IV?

I want to encrypt data using AES in java, and I want to intialize the cipher with Initialisation Vector. Can I use 256-bits IV ? Or I must use only 128-bits IV ?
1
vote
0answers
93 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 ...
2
votes
1answer
70 views

Does endianness affect encryption keys and initialization vectors?

When encrypting (specifically when using AES) content, will endianness affect how the key (and/or initialization vector) should look when encrypting/decrypting content? And could this depend on the ...
2
votes
3answers
6k views

Is Aescrypt a valid tool for encryption or not?

I'd like to know if Aescrypt is a valid tool, or if for a very secure protection, the only choice is to use a software like gpg, or similar. More I've another curiosity, if one doesn't want to use ...
1
vote
1answer
241 views

AES subkey generation operations order

I am preparing for my Information Security state exam. There is a question in preparation sheet that asks about order of operations to generate subkey for AES algorithm. Operations listed: XOR with ...
13
votes
3answers
20k views

Key size difference between AES and RSA

Can I say that 128 bit using AES provide more security than 1024 using RSA?
3
votes
1answer
76 views

How can the parallelization in CTR mode be attained?

I am using CTR mode to encrypt/decrypt files. Theoretically CTR mode is faster than CFB or CBC because of its individual operations on blocks. In my case CTR mode takes almost as long as CFB. How can ...
15
votes
2answers
3k views

Does AES-192 provide better encryption than AES-256?

this wikipedia article describing AES says: Related-key attacks can break AES-192 and AES-256 with complexities 2^176 and 2^99.5, respectively. Does this mean that AES-256 is actually a weaker ...
-2
votes
1answer
93 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 ?
3
votes
1answer
3k views

Using AES as a Stream Cipher

I need to send a lot of small messages that are usually between 128 bits and 256 bits long, and each message is encrypted with a separate 128 bit AES key. Therefore, to send each message with the key ...
-2
votes
1answer
211 views

What is encryption by RSA with AES? [duplicate]

By visiting some websites, like bank websites, we can see for example: TLS_DHE_RSA_WITH_AES_128_CBS_SHA, 128 bits, TLS 1.0 I would like to know: What does mean CBC? TLS 1.0 is an old version, is ...
0
votes
2answers
237 views

Would AES encryption of a small number of blocks be less secure than encrypting a large, fixed-size padded buffer?

My application encrypts a file with AES, and the data is read, encrypted and written with a buffer. It's size is defined with a BUF_SIZE value, which is constant. I will try to explain my question ...
5
votes
3answers
239 views

Secure Hash of a very short payload - is it possible?

I am looking to verify the integrity of a very small payload, approx 64 bytes, which will be stored in a QR code. I need to verify that the payload has not been generated or altered by an attacker. ...
3
votes
3answers
398 views

Are credit card number look ups more secure with a hash function than with a deterministic encryption algorithm?

I understand PCI DSS 3.0 allows hashes of cardnumbers to be stored separately from encrypted values, but I'm startled at the efficiency of tools like hashcat in discovering card numbers from hashed ...
1
vote
1answer
527 views

Does AES 256 encryption support a master key and generated (time-bombed) keys?

I have a scenario where semi-sensitive [1] data for a corporate web application is to be stored in the browser's localized storage (Indexed DB to be specific, via JavaScript). The intention is to ...
3
votes
2answers
131 views

Consequences of putting a serial number into an AES key

I have an embedded device with a secure memory of only 128 bits. I have to store the serial number (16 bits) and the AES key (128 bits) into this space. What are the consequences of putting the 16 ...
-1
votes
3answers
357 views

If TLS 1.2 is considered unbreakable, why do the NSA and other agencies invest in supercomputers? [closed]

If a 2048-bit RSA key and a 256-bit AES key are considered to be unbreakable within the foreseeable future by any kind of computer, why do the NSA and other intelligence agencies invest in ...
4
votes
5answers
537 views

A secure way to encrypt a connection between 2 clients securing against both passive and active adversaries

Recently I got interested in encryption and the methods behind them. So for a fun / school project I am building a program in python to encrypt data between two clients (chat and files). I'm just ...
1
vote
2answers
207 views

Encrypting user credentials using AES: how to hide the key

One of my software (an R package) has to save on disk users sensitive information. I encrypt such information using AES encryption using a random key that is generated at the moment of installation (...
3
votes
0answers
480 views

How does Silverlight protect the AES keys it gets from PlayReady? [closed]

I'm doing some research about how Silverlight protects AES keys. Here is the scenario: There is a smooth stream live encrypted channel service. When i log in to the service and tune the channel, ...
0
votes
0answers
185 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 ...
0
votes
1answer
3k views

Cracking Kingston DataTraveler vault privacy - is it possible?

I have Kingston DataTraveler vault privacy USB flash drive (DTVP/2GB). Here is tech specs. Flash drive has a 256-bit AES hardware based encryption. My flash has password protected and I do not know ...
2
votes
1answer
353 views

OpenSSL implemented AES not according to NIST?

I have been using the Encryption/Decryption code from https://wiki.openssl.org/index.php/EVP_Symmetric_Encryption_and_Decryption. The NIST test vectors (http://csrc.nist.gov/groups/STM/cavp/) for AES ...