Questions tagged [entropy]
Entropy is a measure of how predictable the outcome of a random process is, or how much uncertainty one has about an unknown quantity in one's state of knowledge, defined in terms of the probability distribution on possible outcomes or quantities.
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Public Key Calculation in LMS
In RFC 8554 "Leighton-Micali Hash-Based Signatures", in section 4.3, the generation of the public key is described. The iterative hash function inputs is $I \| u32str(q) \| u16str(i) \| ...
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Password entropy, or at least establishing reasonable upper and lower bounds on it
I use, and have always used, cryptographically secure randomness as a source for my passwords. However, the final coding of that random stream into something a website will accept as a password has ...
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Does the actual length of a password or salt provide any additional entropy to that contained within them?
I refer to the following wiki description of the Argon2 key derivation function:-
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Are USB TRNGs still useful given the recent /dev/(u)random merger?
I'm referencing Jason A. Donenfeld's Random number generator enhancements for Linux 5.17 and 5.18 available here. In summary:-
significant outward-facing change is that /dev/random and /dev/urandom ...
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equivalence between entropic perfect secrecy and single probability
i'm new to information theory.
I know the standard perfect secrecy definition:
$$
P(M=m|C=c) = P(M=m) ,
$$
for all $m$ and $c$, respectively the message and the cypher.
Now, i can use the entropic ...
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Is this probability negligible?
Let $X \in \{0,1\}^{2n}$ be a uniformly distributed random string and $Y \in \{0,1\}^{2n}$ such that $H(Y) = n$.
Does this imply that $Pr(X=Y) = 2^{-n}$? If it's not, is this probability necessarily ...
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Relation between seed entropy of a CSPRNG and the output entropy
Since Linux 5.18, the internal state of the ChaCha-based CSPRNG is a 256 bits (32 bytes) BLAKE2s hash. There is also a fast key erasure mechanism which reseeds the CSPRNG every minute (source).
I know ...
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How much entropy is lost due to collision?
If entropy is hashed with SHA-256 for example, and the input has exactly 256 entropy bits, how much entropy is reduced after hashing due to collision? Is there any reference that explains how to ...
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Entropy extraction from a Zener diode TRNG
My project is to build a true random number generator that relies on the avalanche effect in a Zener diode. This for a messaging device that uses one-time-pad encryption. Reading about similar ...
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Entropy output from 256-bit Argon2 input [duplicate]
I would like to deterministically derive two different 256-bit keys from a single passphrase -- one used as an ECDSA private key, the other as a symmetric key for AES-GCM.
Would a KDF output ...
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Should I Test A PRNG Using A Fixed Entropy Source For Its Seed?
I want to test a C implementation of Hash_DRBG—which test_demo.c file I will modify to produce random binaries indefinitely to STDOUT as to be used by piping its output—using DIEHARDER for a research. ...
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Is there any way to measure entropy of encryption algorithms in python?
I am new to cryptography and I am trying to find a way to measure ciphertext entropy of encryption algorithms such as AES, Chacha20, etc for a school project. Is there any way to do it on Python? I ...
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Manual entropy collection from sources with an arbitrary base
I'm writing a tool for manually collecting entropy from sources like coins and dice, and I'm wondering how to best deal with the case where the desired number of bits of entropy is not representable ...
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How large should a seed possibility space be to generate a secure ECDSA key pair?
I have a function that generates a random 16 character length (upper + lower case letters plus numbers) seed password:
...
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From Entropy's perspective how Encryption affects a Message?
How Ciphers, specifically, Substitution Ciphers and Transposition Ciphers manipulate the Entropy of Plaintext w/wo the aid of Entropy Source?
Reversely, how Decryption manipulates the entropy of ...
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