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Is it possible to test implementation for side-channel attacks?

When it comes to implementing cryptographic algorithms, there seems to be a big focus on the difficulty of doing so without introducing the potential for side channel attacks and the knowledge required. Along with that seems to go the assumption…
DasIch
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Password entropy much lower than entropy of encryption keys. Why is this acceptable?

When talking symmetric encryption, a 56 bit key is known to be so weak. If you use it for your encryption, you are considered a goner. When talking passwords however, the standard these days is about 8 characters selected from about 94 characters…
Minaj
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Is there a way to make RC4 (ARCFOUR) secure, or is it completely broken?

I need a method to authenticate a process with another in order to establish interprocess communication between them, to prevent malicious processes from trying to hook onto the system. Currently I just send a password in plaintext between the two…
Kevin Jin
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Can Elgamal be made additively homomorphic and how could it be used for E-voting?

Elgamal is a cryptosystem that is homomorphic over multiplication. How can I convert it to an additive homomorphic cryptosystem? How can I use this additive homomorphic Elgamal cryptosystem for E-voting purpose? Please explain with examples.
Nazmul
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4 answers

Is it possible to pick your Ed25519 public key?

Is it possible to generate an Ed25519 keypair that has a very similar public key as another keypair (fooling a casual visual comparison) or is this as hard as solving one of SHA-512 or the discrete logarithm problem?
joeforker
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Noise in Homomorphic encryption

What is the noise in homomorphic encryption schemes? (or where does the noise come from, I see that its inbuilt in the scheme and is not a side channel or disturbance noise) Is it also due to the noise that HE is a probabilistic scheme ?
1010101
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Should RSA primes $p$ and $q$ differ in length by "a few digits"?

When generating RSA keys in the original RSA paper it is stated: to gain additional protection against sophisticated factoring algorithms, p and q should differ in length by a few digits Why is this? How many is "a few digits"? And how important…
gtrwoot
13
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0 answers

Yaos Millionaire Problem: Why distance >= 2?

I'm currently reading about Yao' Millionaire Problem: http://research.cs.wisc.edu/areas/sec/yao1982-ocr.pdf Alice and Bob want to know which of them is richer. Let $j \in \{1, \cdots 10\}$ be Bobs fortune, and $i$ Alice's. They share a…
Calculatrix
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Why do we use hex output for hash functions?

Why do we use hex representation as default for the output of a hash function's result? For example, the SHA-256 hash function: the output of SHA-256 in hex representation uses 64 characters, while using Base64 on the raw output produces 44…
Neil Yoga Crypto
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Why can't the IV be predictable when its said it doesn't need to be a secret?

I heard multiple times not to reuse the same IV and IV should be random but doesn't need to be secret. I also heard if the IV is something like sequential numbers or something predictable I should hash(salt+pepper) it. Why on earth should i be doing…
user2651
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2 answers

RSA encryption using multiplication

Generally in RSA we encrypt as $m^e \pmod n$. Will RSA work if we replace the power by normal multiplication? $E = (m \times e) \mod n$ and decryption as $c \times d \mod n$. What will be $d$ disadvantage if it works ?
Vinny
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How should I store passwords that need to be available in plain text?

Suppose I need to store login information for a third-party website for a few users, how would I go about doing it? Since I am logging into a third party website, I need the password in plain-text, not hashed. And no, the website in question does…
user93
13
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1 answer

What are the requirements of a key schedule?

In the first block cipher I designed I used a CSPRNG to generate the round keys. The purpose was to at least have a chance of creating a (hopefully!) secure cipher on the first try (but please don't use it in production). One criticism I got was…
Demi
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Which cryptography technique does not increase the size of the plain data?

I want to encrypt some data(text/voice/video) but it is essential that the size of the cipher data remains the same as the plain data. Which techniques can I use, and how secure are these techniques as compared to the ones which increase the size of…
Jay
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Uniformly distributed secure floating point numbers in [0,1)

Is there any way to generate cryptographically secure uniformly distributed floating point numbers in the interval [0,1)? For example, in Javascript, there is Math.random(), which yields these (pseudo-random) numbers, yet not cryptographically…
serv-inc
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