Linked Questions
33 questions linked to/from What are the rules for using AES-GCM correctly?
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Is E_k(M)||H(m) form of MAC secure?
Would this encryption and signing scenario be considered tamper-proof?
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453
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With AES-CTR does the block input need to be implemented as nonce || counter?
I am looking at an AES-CTR implementation (WebCrypto) and it takes an initialization parameter count which is an array of 16 bytes. It then asks you to specify <...
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The Rationale behind NIST's counter/LFSR recommendation on deterministic IV constructions on SP 800-38D
The NIST has a "SP 800-38D: Recommendation for Block Cipher Modes of Operation: Galois/Counter Mode (GCM) and GMAC". This guideline is a base for AES-GCM from definition to security ...
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2
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How is AES256-GCM auth tag used in decryption
I have been playing with AES256-GCM in NodeJS crypto library and it shows that the original message can be decrypted without caring about the auth tag.
So can a non-tag verified decryption be secure? ...
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AES CTR - Counter Management
Let ssuppose that we are using AES in CTR mode to encrypt a number of blocks ($x$ bytes each).
How is the current used IV (nonce+ctr) synchronized among both communicating entities?
I suppose that the ...
- 297
2
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1
answer
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What does AES-GCM provide?
I am wondering does AES-GCM which uses Authenticated Encryption provide us with all 3 properties (Authenticity, Confidentiality, and Integrity), or does it not provide integrity?
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Alternative to CBC mode encryption?
Given that CBC mode encryption is vulnerable to padding oracle attacks, what is the next best alternative ?
a) Include a hash check in the API scheme, validate the hash and then proceed with CBC. If ...
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2
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2
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How much data can we encrypt using AES 256 before changing the key?
Although this question has been answered in this link (After How Much Data Encryption (AES-256) we should change key?), I am not satisfied with the answers because the Recommendation for Block Cipher ...
- 21
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Consequences of AES-GCM always encrypting the same plaintext
I am analysing an authentication protocol. In this protocol AES-GCM is used to encrypt part of the messages.
Regarding the authentication protocol, I made the following observations:
The plaintext ...
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2
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444
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Is it cryptographically insecure to use fixed-length AES-GCM messages?
Is there any weaknesses to encrypting fixed-length messages? Should a random amount of padding be added to the message to decrease the odds of some sort of attack?
user256686
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1
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Is a random string good for an AES-256 instance
I have a randomly generated string of about 256 characters long. This string is hashed to for a key and initialization vector for a program running on the .NET framework 4.8. Is this method secure ...
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1
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Do I need to change IV in AES-256 GCM when I only use encryption for challenge-response exchange with random string?
When I want to use encryption only for challenge-response exchange and not for hiding the contents of an encrypted message, is it still a threat to me not changing IV for new encryption?
For easier ...
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1
answer
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Why are iterated substitution-permutation product ciphers only used on fixed-size plaintext blocks?
Another way to ask this question: when block ciphers were invented, why did they add the restriction that the block cipher would be restricted to blocks of a fixed size?
From my laymen's point of view,...
2
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1
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End-to-end photo storage
I've been tasked with developing an app that will need to store photos a user takes securely, and I've been struggling to think up a method to do this.
What I was thinking so far is as follows:
When ...
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Is it possible to uncover the plaintext if IV is used twice but the key is different?
I am currently working on a cryptography challenge. The program uses AES-GCM to encrypt and decrypt strings.
Let's say I have the following:
IV which is reused
only 1 cipher text
authentication tag
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