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Questions tagged [initialization-vector]

121 questions
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Encrypt and decrypt using PyCrypto AES-256

I'm trying to build two functions using PyCrypto that accept two parameters: the message and the key, and then encrypt/decrypt the message. I found several links on the web to help me out, but each one of them has flaws: This one at codekoala uses…
Cyril N.
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Good AES Initialization Vector practice

per my question Aes Encryption... missing an important piece, I have now learned that my assumption for creating a reversible encryption on a string was a bit off. I now have public static byte[] EncryptString(string toEncrypt, byte[]…
Jeremy Holovacs
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AES encryption how to transport IV

I understand that unique IV is important in encrypting to prevent attacks like frequency analysis. The question: For AES CBC encryption, whats the importance of the IV? has a pretty clear answer explaining the importance of the IV. Would there be…
RunHolt
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Secret vs. Non-secret Initialization Vector

Today I was doing some leisurely reading and stumbled upon Section 5.8 (on page 45) of Recommendation for Pair-Wise Key Establishment Schemes Using Discrete Logarithm Cryptography (Revised) (NIST Special Publication 800-56A). I was very confused by…
Hut8
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What is an openssl iv, and why do I need a key and an iv?

I am about to use the following script to encrypt and decrypt some data. I am using it because my current encryption does not work on our new server. We are currently using mcrypt so I want to change to openssl. In our database we use aes encryption…
Thomas Williams
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Generating random IV for AES in Java

I'm implementing and AES encryption engine for PBE in android, and I've found two ways to implement the creation of the IV and I would like to know which one is better and more secure for getting IvParameterSpec: Method #1: SecureRandom…
user1576396
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Characteristics of an Initialization Vector

I'm by no means a cryptography expert, I have been reading a few questions around Stack Overflow and on Wikipedia but nothing is really 'clear cut' in terms of defining an IV and its usage. Points I have discovered: An IV is prepended to a…
Jamie Chapman
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PyCrypto - How does the Initialization Vector work?

I'm trying to understand how PyCrypto works to use in a project but I'm not fully understanding the significance of the Initialization Vector (IV). I've found that I can use the wrong IV when decoding a string and I still seem to get the message…
Tim Tisdall
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Why is random IV fine for AES-CBC but not for AES-GCM

I have been using AES-CBC for encryption and I use a random IV each time I encrypt plain text. As far as I can tell, this is the recommended approach. I have been looking into AES-GCM / AES-CTR, primarily for the AEAD. I have not yet implemented…
garys
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Need solution for wrong IV length in AES

I'm trying to implement AES in Java and this is the code I use: byte[] sessionKey = {00000000000000000000000000000000}; byte[] iv = {00000000000000000000000000000000}; byte[] plaintext = "6a84867cd77e12ad07ea1be895c53fa3".getBytes(); Cipher…
Shahed
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CTR mode use of Initial Vector(IV)

from what I know, CTR mode doesn't use an Initial Vector. It just takes a counter, encrypts it with a given key and then XOR's the result with the plaintext in order to get the ciphertext. Other block cipher modes like CBC before doing the…
Antonys
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Storing the Initialization Vector - Separate field?

When encryption sensitive information using the .NET AesCryptoServiceProvider library I generate a unique Initialization Vector (IV) for each value that is encrypted. In the database record where I save the encrypted data I have a field named "IV"…
webworm
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AES-GCM with BouncyCastle throws "mac check in GCM failed" when used with IV

I'm relatively new to developing something with encryption. Right now I'm trying to write a class which encrypts and decrypts Strings using BouncyCastle with AES-GCM. I read about the things you have to consider when implementing encryption. One of…
thaasoph
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Generate random bytes Cocoa?

I need to generate some random data to append to my file for encryption. How would I go about doing this? Would it be sort of the same idea as generating a string of random characters? Something like: NSData *randomData = @"what should i put…
user762034
5
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AES 256 Encryption -> Changing inititialization vector slightly changes decrypted message without knowing key

I made the following observation with an AES encrypt/decrypt example which is very counter intuitive for me. I tried to encrypt and the decrypt a simple payload with AES in CBC mode. My understanding is/was that the initialization vector does not…
DanEEStar
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