Linked Questions

13 votes
1 answer
5k views

Why do we encrypt-then-mac but sign-then-encrypt?

This question was asked in comments on my answer to Should we MAC-then-encrypt or encrypt-then-MAC? I think posing the question as a separate entity is best, so: The general advice for applying MACs ...
1 vote
1 answer
6k views

Hash-Then-Encrypt or Encrypt-Then-Hash?

The question is about site-to-site transmission where the recipient needs to decrypt the incoming data. What method is more secure and make it harder to decrypt, Hash-Then-Encrypt or Encrypt-Then-Hash?...
151 votes
7 answers
110k views

Should we sign-then-encrypt, or encrypt-then-sign?

Frequently, we want to send messages that are (a) encrypted, so passive attackers can't discover the plaintext of the message, and (b) signed with a private-key digital signature, so active attackers ...
0 votes
1 answer
98 views

Does sending encrypted hash inside message compromise security

This might sound like a naive question (And maybe it is (It's an early morning Saturday thought, so there might be some clarity of thought missing)). Suppose we havea protocol that sends messages as ...
2 votes
2 answers
105 views

Using the MAC to verify if Cipher Only attack has succeeded

I am working on an experiment to compare the efficiency of brute-force attacking block ciphers like AES and DES with reduced key sizes for different programming languages and library implementations. ...
1 vote
1 answer
122 views

Hash-Then-Encrypt or Encrypt-Then-Hash on Keyed Hash Functions

I have seen other answers here on Stack Exchange regarding MAC-Then-Encrypt vs. Encrypt-Then-MAC (and this article regarding MAC-Then-Encrypt padding oracle attacks on SSL) as well as generic Hash-...
3 votes
1 answer
479 views

Digital signature and salt

I'm wondering whether is of any use to add salt when computing a signature of a piece of data. I looked around but didn't find an answer to this, although there's a very similar question: Why hash or ...
1 vote
1 answer
101 views

Disk encryption and advanced format

As far as I understand, the biggest problem of requesting authentication in disk encryption is that the plaintext and ciphertext are not having the same size -because of tag-. The XTS mode is already ...
3 votes
3 answers
5k views

Is CTR more secure than CBC?

In cryptography, a block cipher mode of operation is an algorithm that uses a block cipher to provide information security such as confidentiality or authenticity. A block cipher by itself is only ...
3 votes
2 answers
492 views

Are the following ciphersuites vulnerable? if so, what are the vulnerabilities?

Following ciphersuites found to be weak in Qualys(https://www.ssllabs.com/ssltest/analyze.html) tool: TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256 (0xc027) ECDH x25519 (eq. 3072 bits RSA) ...
2 votes
2 answers
234 views

What drivers are causing an increase in authenticated encryption modes?

So I'm currently working through this cryptography question and so far I have the answer of an increase of hackers due to increase in computational power. But apart from that I don't know what else. ...
2 votes
1 answer
467 views

CPA secure to CCA secure encryption

Can we use a MAC to transform a CPA secure encryption scheme into CCA secure one?
8 votes
3 answers
1k views

Is there a companion algorithm for OTP to ensure integrity and/or authentication?

One-Time Padding is (theoretically) perfect encryption algorithm. Let's assume that these problems are solved: Fast generation of independent and identically distributed random variables Perfect key ...
3 votes
2 answers
404 views

Is disabling padding integrity check in CBC implementations a good way of overcoming / mitigating padding oracle attack?

Given that CBC mode has a padding oracle attack, would disabling the padding integrity check be a good way of overcoming the vulnerability (this may result in frustration among existing users with ...
-1 votes
1 answer
98 views

Simplification: Should we MAC-then-encrypt or encrypt-then-MAC?

I refer to Should we MAC-then-encrypt or encrypt-then-MAC?. There are 15 answers (today) with many words. It is difficult to tell which is the correct(?) answer. Also, the question excludes the ...

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