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 safe to write the salt AND/OR the IV at the beggining of an encrypted file?

I want to encrypt a file with AES in CBC mode (maybe another mode is better for file encryption...I don't know, but suggestions are welcome!). What I usually do is that I first write a few random ...
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2answers
210 views

Is AES feasible for secure hashing files? [closed]

There was already a similar topic "Why AES is not used for secure hashing, instead of SHA-x?", but it was not about files specifically, and I, personally, am not convinced by the answers in it. "AES ...
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1answer
116 views

Sending Salts For Key Generation

I am working on a project that uses a combination of a web based framework (Django) and an installed app (Python) for the purpose of data entry/upload. I will have to send medical records over the web ...
0
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1answer
34 views

Is embedding the EAX nonce inside the Associated Data considered safe?

As the nonce bits would be used twice in that case, does that break EAX security? The examples I've seen using EAX have separated the nonce from the Associated Data, but to me it makes more sense to ...
0
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2answers
971 views

What is the advantage of using a symmetric cipher like AES to generate a keystream?

I see examples of AES (with a shared secret key) being used to encrypt shared secrets (e.g. nonce + counter) to produce a keystream against which the plaintext is XOR'ed to produce the ciphertext. ...
0
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1answer
79 views

Encrypting data in a load-balanced application - am I doing this right?

A web application I'm developing needs to store some sensitive data in a database. I need to be able to retrieve and use this data later on so hashing isn't enough. The web application might, at some ...
0
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2answers
620 views

Security of several files all using same password/key (7zip, AES256)

I'm working on a simple secure mirror for potentially untrusted services like Dropbox, Owncloud and so on. (Current code may be seen here: http://www.codeduce.com/extra/secure_mercurial) Currently ...
3
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2answers
2k views

Why would you need a salt for AES-CBS when IV is already randomly generated and stored with the encrypted data?

I was looking at this code and came across these comments which says encrypting without a salt is insecure. Why would it be insecure when you are already using a random IV for each value? I think the ...
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4answers
223 views

Is knowing 'a' encrypted with 'b' and 'b' encrypted with 'a' a possible threat?

Excuse me for question name, but I couldn't find any other suitable title. I want to validate client connecting to the server. My algorithm looks like that: Clients sends his login - plaintext ...
3
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1answer
775 views

Salt usage for Spring security?

I use the Spring security for Java web applications and I have written an authentication provider which is working without salt and now I want to either add salt or alternatively use the built-in ...
5
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2answers
154 views

Benefit to using PBKDF2 on key generated by RNGCryptoServiceProvider?

I have a program that generates a fixed-length 32 byte (256-bit) password using RNGCryptoService provider and then uses Rfc2898DeriveBytes on that password to arrive at an encryption key. However, to ...
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3answers
372 views

Is applying AES multiple times safer?

The KeePass security help page talks about preventing dictionary attacks To generate the final 256-bit key that is used for the block cipher, KeePass first hashes the user's password using ...
3
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1answer
75 views

Confused about symmetric 128,256 key and the secret provided

I have searched and searched but cannot locate an answer to my question so I am hoping the experts here can. When I read about symmetric encryption like AES I see mention of the key and key size such ...
7
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2answers
570 views

How to circumvent compromised CPUs in major FOSS operating systems

As Matthew Green puts it, "the NSA has been ... Working with hardware ... vendors to weaken encryption and random number generators." At this stage, however, there is little public knowledge of which ...
0
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1answer
326 views

Can SHA-1 PRNG still create secure cipher keys?

I am concerned that a SHA-1 PRNG cannot produce an AES-256 cipher key with the expected 256 bits of security, or indeed any secure cipher key where over 165 bits of security are expected. The SHA-1 ...
13
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4answers
5k views

Is “Why Should You Avoid AES In MySQL?” true?

From a 2012 Smashing Magazine article quite a bold statement is made to avoid AES in MySQL itself. Or as they put it "Why Should You Avoid AES In MySQL?". However, if you search for SQL encryption, ...
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2answers
254 views

Do I need to salt PBKDF2 when it's used for AES encryption

If I'm using PBKDF2 to stretch a password into a suitable key for use in encryption with AES, should I be using a random salt (for PBKDF2, not the AES IV)?
0
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1answer
71 views

What key needs to be used to compute HMAC?

I use AES-128bit to encrypt files and I want to compute a HMAC for each one of the encrypted files to ensure their integrity. Can I use directly the AES KEY to compute HMAC or should I used a derived ...
3
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2answers
679 views

Using AES to encrypt user data

I know next to nothing about cryptography, and I'm basically just looking for someone to look over what I'm doing and tell me if I'm screwing up. I have the user entering in some sensitive ...
2
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2answers
119 views

How safe is Money Toolkit?

Money Toolkit is a smartphone app that can alert you to your balances and transactions across multiple accounts. I was reading their site and whether their practises are as secure as they claim to ...
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3answers
3k views

How long (in letters) are encryption keys for AES? [closed]

How long is the encryption/decryption key for an assymetric algorithm, such as AES? If I use AES 128-bit, how many characters should I type in for my key? What about AES 256-bit? Edit: Here is why I ...
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2answers
68 views

Using SSL for a single request

I want to use distributed cluster configured like: xx.resource.server.com. xx - can be anything from aa to zz, most of the requests will be one time. I need the connection to be secure between client ...
2
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1answer
533 views

AES key management

I am encrypting a secret in a db field. I am encrypting using AES with a 256-bit key and a random IV per encryption. They AES key is hard coded in the code. Each IV is stored in clear in another ...
4
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2answers
5k views

Using AesCryptoServiceProvider in C#, should using an incorrect IV mangle just the first block?

This question was also asked on StackOverflow, but with no answers, and I thought this may be a better exchange, since I have the same question. ...
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1answer
318 views

MySQL AES Encryption - Is it good idea to store 3rd Party Auth Tokens using AES Encryption?

I need some advice on MySQL AES Encryption. I'm developing an application which connects to various 3rd-Party APIs and retrieves the Access Tokens for the application users. These Access Tokens are ...
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1answer
120 views

Permutation in Block Ciphers

I was reading some e-books to understand the basics of block ciphers and how it works in AES. As i understood, Permutation plays a big part in AES and Block Ciphers, Here is what i understood by ...
2
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1answer
2k views

How safe is the new iOS Keychain that stores credit card numbers?

iOS7 includes iCloud Keychain which syncs your stored passwords across devices. Not only that but it also syncs credit card numbers. The only information I can find about encryption is that they are ...
6
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2answers
1k views

Should AES always give the same output?

I'm having trouble understanding AES and would like to know if encrypting the same text with the same key two times in a row should give the same output. Is there any salt or something that would ...
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1answer
199 views

Is there symmetric encryption like AES or Camelia with keys longer than 256 bits?

I am wondering if is there any (secure!) cipher like AES or Camelia with keys longer than 256 bits (and offering higher security than 256 bits). I have not found anything except ...
5
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1answer
3k views

What block ciphers and algorithms are now safe? [closed]

I work for a large non-US based international organisation. Regarding the recent leaks about the NSA breaking most encryption on the internet, we now know the US and UK governments are actively ...
4
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2answers
1k views

How much does unknown PBKDF2 iteration count improve security?

We are crackers who get our hand on an encrypted file. We know the whole file is AES-256 encryption of the original plaintext file. We also know that PBKDF2 was run 1000 times on the original plain ...
1
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1answer
330 views

Questions towards my application that uses bouncy castle crypto

I am implementing an application using bouncy castle crypto API it uses AES-CBC to encrypt files and i have some questions regarding the development of my application. I dont want to use a static ...
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1answer
213 views

Different AES 256 algorithms produce different results?

I've tried 3 AES 256-bit CBC encryption programs, and I seem to be getting different results for each one with the same 32-character password, which consists of all @ signs. They are: Polaris SSL ...
4
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2answers
205 views

question on hashing an aes-encrypted file

I am storing multiple sensitive data on a server that I do not own. The data is encrypted using aes-256 using cbc mode. The keys are only with me, and are stored securely. I am worried about the data ...
1
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2answers
86 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 ...
0
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2answers
123 views

How is the key obtained when I login via VPN?

So, I configure my VPN (let say which uses PPTP protocol), enter the server name, username and password. Then, I visit a website. Before that, my request is encrypted using AES with some key. That ...
5
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4answers
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Is 1Password more secure than an AES encrypted text file?

Are there extra measures taken by 1Password and KeePass, that make them more secure than an AES-256 encrypted text file? The database formats they use seem needlessly complex for my own purposes.
5
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2answers
739 views

Designing a cryptographic file-sharing protocol

As a learning project, I am trying to implement a secure way to share files with a friend over dropbox. (I am not looking for existing software, I am doing this in order to learn how to do this ...
3
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2answers
246 views

Is splitting up an AES Key a problem?

I'm wondering if it would be a problem to split up a 256 bit AES-Key into two 16-Byte blocks and distribute it, to implement some kind of a four-eyes-principle (you need two persons to decrypt a ...
9
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2answers
9k views

Recommended options for LUKS (cryptsetup)

I'm looking for recommended options for cryptsetup to create fully encrypted SSD (SanDisk SSD U100 128GB), which achive: Timing O_DIRECT disk reads: 1476 MB in 3.00 seconds = 491.81 MB/sec Timing ...
5
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1answer
835 views

When do I use NIST AES key wrapping?

Key Wrap constructions are a class of symmetric encryption algorithms designed to encapsulate (encrypt) cryptographic key material. The Key Wrap algorithms are intended for applications such as (a) ...
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1answer
550 views

How to encrypt by AES-Twofish-Serpent

I was wondering how to encrypt by doing a AES-Twofish-Serpent encryption. Does this mean I encrypt in AES first then after that in Twofish, and after that in Serpent (three separate encryptions). ...
0
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2answers
431 views

Can AES-256 encrypted data be changed?

I have a file that supposedly contains AES-256 encrypted data. The file was created using a proprietary program that claims to use AES-256. I have tested decrypting the file with an open source ...
7
votes
1answer
977 views

What's the hash for in ECDHE-RSA-AES-GCM-SHA?

Presumably the SHA is for deriving the AES key from the shared secret. Where else is the hash used? ECDH just does ECC (no hashing). RSA does masking and padding but this doesn't involve the ...
0
votes
3answers
835 views

Ways to keep AES encryption key safe.? [closed]

I am using AES encryption to secure some sensitive data. For that i have to provide a certain key for encrypting and decrypting. It's not safe to keep the key somewhere on the server. So instead of ...
2
votes
1answer
105 views

Does padding an AES key hurt security (besides lowering the strength of the key)? [closed]

I've been reading about solitare and its weaknesses, and thinking about clever ways of hiding keys. It seems like you could encode an 52-bit AES key in the vertical orientation of cards in a deck (or ...
7
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3answers
4k views

How can I securely convert a “string” password to a key used in AES?

I'm writing some software where I have to encrypt all files that are written to a specific folder using AES. There is one password/key that is configured somewhere, that is always used. I don't want ...
9
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5answers
5k views

SSL/TLS - Distinction between self-signed cert and self-signed CA, and other questions?

I have a small personal website which I wish to serve securely over HTTPS. At the moment I do not wish to use a third party CA to sign my certs. I was reading this document on generating a self-signed ...
1
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1answer
466 views

Using Apple NSKeyedArchiver class without encryption to save score data locally

first of all I'm sorry for my bad English! I have a question about the security of NSKeyedArchiver, a subclass of NSCoder of Apple Foundation.framework ...
5
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2answers
119 views

Serving data from an encrypted database over an encrypted connection

There is encrypted data in the database (asymmetric FYI). It is to be viewed as decrypted on the website. The data can be sent to the client as encrypted to be decrypted on the client's computer, or ...