# All Questions

19,143 questions
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### Perfect secrecy and known ciphertext length

From what I understand perfect secrecy means that the probability distribution of the messages are independent of the cipertext, right? How can the one time-pad be perfectly secret when the ciphertext ...
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### Libsodium not decrypting AES-256-GCM [on hold]

I posted this question earlier but it was moved as it was deemed a programming question but I don't think it is. I think it's me not understanding how AES-256-GCM decryption works. I'm trying to ...
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### Boneh-Franklin Identity-based encryption scheme [on hold]

Could you please explain to me the for algorithms used in Boneh-Franklin identity-based encryption scheme. These algorithms include setup, extract, encrypt and decrypt. For example in the setup ...
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### Where do the constants for SHA-1/2/3 come from?

My request is: I need to know the source of constants (shift constants, IV, or S-Box) for the following algorithms: SHA-1 SHA-2 (all sizes) SHA-3 Examples: BLOWFISH uses the hexadecimal ...
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### Libsodium decryption returns empty response [migrated]

I can't get Libsodium to decrypt a response I'm receiving from a webhook but openssl_decrypt does. I'm not getting an error but I keep getting a blank result which ...
88 views

### Verify partial message given hash of full message

I need to verify partial downloads (retrieved sequentially), given a (preferably short) hash of the complete download. Given a message $m_0 \mathbin\| m_1 \mathbin\| m_2 \mathbin\| \cdots$, hash ...
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### Can I use XOR to establish a longer shared secret?

SIKEp434 can only be used to encapsulate a 16 byte (128 bit) shared secret key. Most encryption algorithms these days (specifically (X)ChaCha20) require a 256 bit key to be secure, especially in a ...
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### Post quantum TLS based web-browser client [migrated]

Are there any open source projects that implement a web browser client that has support for post quantum TLS protocols so that it can talk with post quantum patched TLS web servers. I've checked ...
97 views

### Why is prime number size important for RSA security?

RSA modulus is $N = pq$ where $p$ and $q$ are prime numbers. I read from somewhere that the time it takes to decrypt the RSA encryption increases exponentially as key length increases, which depends ...
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### How to prevent HR forwarding or downloading or printing my Resume? or let the email destroy itself after a time limit? [closed]

I have a bad feeling sending my Resumes to different companies and I think they will save my data. Is there a way to encrypt my Resume? Can I let it destroy itself after a certain time limit? Or just ...
78 views

### What is “spinal-tap grade” security?

As stated here Ed448 is different from Ed25519 because of "spinal-tap grade" security. What does this mean?
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### Induction is problematic in computational cryptography - Why?

In Dr. Lindell's lecture The Yao Construction and its Proof Of Security, in briefly explaining the hybrid argument, he makes the statement that mathematical induction is a problem in computational ...
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### Does the use of English words weaken diceware passphrases

A Diceware passphrase is constructed from a set of words chosen from a 7776-word database, using five dice throws to choose each word. The argument is that each word in the phrase adds about 12.92 ...
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### What's the number of unique possible Cayley tables in a 16*16 grid for XOR'ing single hex characters? [on hold]

A few days ago, I designed and s-box then derived the following Cayley table of all possible XOR outputs of hex digits in the range of ${2^4}$ and was curious how many such "valid" possible ...
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### Why does Hasse's theorem sometimes seem to be invalid?

In order to generate secure elliptic curves, this answer recommends to Calculate the cardinal $|E(\mathbb{F}_p)|$ Check this cardinal is in the hasse interval (with $p$ prime) and to ...
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### integrity and non-repudiation on logs [closed]

If I want to send log files of total 100M and 10M per each file. I want to maintain the integrity and non-repudation for 5 years atleast. And the system on the client side doesn't have a high ...
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### Elliptic Curve Cryptography insecure when input does not lie on the curve?

I am new to Elliptic Curve Cryptography and I was reading up on it online when I came across this link. It stated the following. Unfortunately, there is a gap between ECDLP difficulty and ECC ...
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### Maple code for Decryption using RSA [closed]

i am given a ciphertext 596912 along with n = 823091 and the private key e=17. is there a maple code that i can use to decrypt the ciphertext since i'm not given the value of d, p and q?
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### Reasoning about WebCrypto ECDSA choices: P-256/384/521, SHA-1/256/384/512?

When implementing EC signing/verification in Javascript, the only options available via the WebCrypto API are: Curves: P-256, P-384, or P-521 Hashes: SHA-1, SHA-256, SHA-384, or SHA-512 If I was ...
33 views

### Choice of delta-neighbors in Balloon Hash algorithm

Reference Document: https://eprint.iacr.org/2016/027.pdf According to appendix D section 4 definition 27 each vertex in V has predecessors sampled independently and uniformly at random from the ...
54 views

### Enigma rotation example

According to wikipedia: BDZGO is the expected outcome when doing the enigma chipher on the letters AAAAA with rotors I,II,III and reflector B. ...
99 views

### What is the difference between the adversary and the algorithm?

I recently saw a sketch relating to provable security in a book, regarding the amount of time it takes to factor N where N = pq and p,q are primes. It says that "There is a trivial algorithm which ...