Questions tagged [side-channel-attack]

attacks using information leaked by implementations of cryptographic algorithms to obtain information about keys or (plaintext) data, instead of (or additional to) using cryptographic weaknesses.

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Why does Montgomery Ladder not work for Brainpool curves

According to SafeCurves, the Brainpool curves mentioned there (P256t1 and P384t1) do not support the Montgomery Ladder for scalar multiplication in constant time. I am wondering why this is the case ...
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Does Argon2id provide less protection against side-channel attacks than Argon2i theoretically and/or practically? [duplicate]

LUKS 2 encryption uses Argon2i as the default PBKDF. As the key is used on each access, I guess side-channel attacks are a significant threat factor. However, as I'm not a cryptographer, I am not ...
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109 views

How to express difficulty of breaking crypto when writing?

When writing for both technical and non-technical readers I find my self naturally wanting to write things such as : "..therefore it would be impossible to decrypt the data." When trying ...
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Are side-channels possible in KDFs

Are KDFs such as PKDF2 and HKDF vulnerable to side-channel attacks such as static and dynamic power analysis including the hash type used internally?
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What is the Lord of the Ring(s): Side Channel Attack and What are the results

A recent Paper to appear on USENIX Security 2021 titled as Lord of the Ring(s): Side Channel Attacks on the CPU On-Chip Ring Interconnect Are Practical by Riccardo Paccagnella Licheng Luo Christopher ...
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58 views

Is this constant-time comparison secure?

I was thinking about constant-time comparison and how it differs from "==", when I thought of a simple way that's could be constant-time. Being a beginner in cryptography, I'd like to know ...
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Conditional probability being Constant in Threshold Cryptography

I am working on Threshold implementation of algorithms to prevent side channel attacks. I am not that much proficient in Statistics and Probability theory. I want to know what is the significance of ...
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secp256k1 scalar decomposing and prime field arithmetic

I'm currently studying the elliptic curve secp256k1 implementation. In my understanding, it has efficiently computable endomorphisms: We can find out a pair of number $\lambda$ and $\beta$ from the ...
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Is this “AND” implementation safe against side channel attacks?

I found out that the following is a working implementation of calculating an AND function between XOR masked shares, implementation at Github. It works by calculating parities, whose terms cancel each ...
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Side-Channel Attacks in the Cloud

Let's say we have some very sensitive personal files. At all costs, we do not want any other pair of eyeballs to gaze upon them. We need these sensitive files to be secure and available. So, we have ...
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Dragonfly masked DH

I was looking at Dragonfly key exchange protocol RFC 7664, and it seems to make use of masked Diffie-Hellman in the final part. Generating two random numbers less than group order $q$, $m$, and $r$ ...
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Constant Time algorithms for $\mathbb{Z}/m\mathbb{Z}$, $\mathbb{Z}/m\mathbb{Z}[x]$, and $\mathbb{Z}/m\mathbb{Z}[x] / (f(x))$?

I want to implement some (lattice based) protocols to better familiarize myself with a programming language (Rust). These tend to do arithmetic over rings like $\mathbb{Z}/m\mathbb{Z}$, or "...
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What is a “constant time” work around when dealing with the point at infinity for prime curves?

I've been working for some time, on designing a constant time solution for dealing with the "point at infinity" for prime curves. So, far I'm using the Standard Projective Coordinates for ...
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Constant time arithmetic implementation in DSA

I am trying to understand why it is a hard problem to have formally verified constant time arithmetic for DSA when compared with ECDSA. For instance, in ECDSA implementations of OpenSSL, we have ...
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Hashing of variable-length chunked data leading to leakage of secret key from side channel?

Hypothetically, secret data could be hashed in some schemes in one way or another. Could chunking of the data lead to exposure of secret component through side channel? Say converting a randomized ...
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Why shouldn't cryptocurrency hash algorythms, resist side channel attack?

2015's Argon2 publication suggests that cryptocurrency hashing like password hashing on backend servers should not be subject to side-channel attack: Argon2d is optimized for settings where the ...
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Side channel attack - execution time depends on the size of the key

In my algorith execution time depends on the size of the key. It is a linear relationship (probably). The larger the key, the longer the algorithm takes to run. I have a code in Python so far. For ...
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54 views

Stream slicing operation in block cipher and side-channel attack

My symmetric block cipher works kind of like a stream cipher, but it works on $128$-bit blocks. It generates a $128$-bit block in every round. And at the end of the round, I have to slice it into two ...
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Is “double-and-add-always” a good mitigation against side channel attacks?

In Discrete Log based Cryptography, one of the core operations that one, has to perform is modulo exponentiation. There are many algorithms to choose from, especially, when considering my point of ...
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Have crypto side-channel attacks happened in the wild?

I'm aware of attacks extracting information via timing and volume. But none that care or attack the actual cryptographic algorithm implementation or end up extracting the key. Seeking examples if any ...
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Will OTP provide quantum resistance under 5 conditions?

We already have quantum computing, but when quantum computing becomes commercially available there is a problem for many but not all encryption algorithm. The One-Time-Pad or OTP is the one and only ...
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How to find the output shares of first-order threshold implementation of cubic degree function?

Assume $d=abc$ and to implement first order threshold implementation , the minimum input and output shares are 4 (1*3+1) , and 4 , calculated using ${4\choose 3}$ , Theorem 2. The new TI ...
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Shuffling: Purpose and formal definition

To my understanding, shuffling means simply to permute the elements in vector $\mathbf{v}$ pseudorandomly, using a PRP $\pi (\mathrm{seed},\mathbf{v})$. A secure PRP should yield a permutation ...
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What quality of randomness is needed for randomized side channel countermeasures?

Using per-operation randomness is a popular and effective way to protect cryptographic implementations against side-channel attacks, e.g. using Shuffling (randomizing the processing order eg for AES ...
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Constant time multiplication in GF(2^8)

I am trying to implement AES in C; I would like to make it resistant to side-channel attacks but I can't implement the multiplication in constant time. My current code: ...
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How to implement arbitrary s-box in a side-channel-free way in C?

This could be a question for CodeReview.SE, but I thought it might require non-trivial cryptographic knowledge to merit it on-topic here. The C language is chosen as it's a common language for ...
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How vulnerable are SIMD operations to side channel attacks?

For a while, I was experimenting with optimization of several crypto implementations with SIMD (Single Instruction Multiple Data ) made available by C compiler ...
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Safely sorting secret data

Suppose you have a secret list of n distinct integers. How would you sort this list in a way that is not vulnerable to timing attacks? I tried looking up "...
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Is AES without T-Tables nor S-Box resistant to side-channel?

T-Tables and S-Boxes are prone to side-channel attacks, is an implementation without any lookup tables resistant to side-channel ? In this answer, https://crypto.stackexchange.com/a/63520/80926, the ...
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150 views

Is AES S-Box resistant to side-channel attacks?

I know that implemntations with T-tables such as Golang's are prone to side-channel attacks, but is AES's S-Box wihtout any additional table also insecure ?
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Timing attacks on homomorphic encryption

I've been wondering for a long time about programs that could potentially break fully homomorphic encryption schemes: ...
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Application of Non-deterministic Processors in side channel attacks

I was reading the abstract of "Non-deterministic Processors" paper by "David MayHenk L. MullerNigel P. Smart", in the abstract, they have mentioned the Kocher paper about "Timing Attacks on ...
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How to prevent cache timing attack on table lookup AES implementation?

I've been trying to find a solid method to prevent cache timing or other possible side channel attacks on an AES implementation, that uses lookup tables for S-box substitution. I realize that there ...
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How does breaking AES with a side channel attack (CPA) differ from a side channel attack on something like a microcontroller?

I'm studying CPA side channel attacks. CPA stands for Correlation Power analysis and it can be used to break AES. I'm familiar with the process to crack AES on a microcontroller. I was just wondering ...
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Does clustering the AES Sbox look up table to 32 bit entry per index, help reduce vulnerability to cache timing attacks?

I've been searching for some, easy methods to help mitigate, a cache timing attack on software AES implementations. Currently, my implementation uses, a usual 256 byte S-box ...
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Is it possible to perform CPA(Correlation Power Analysis) when attacker has only specific round's waveform?

I read Quite a lot document about breaking AES using CPA. But most of them, assuming that attacker has the first or last round of the waveform(trace) and exploit SubBytes. My question is if the AES-...
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How to confirm my implementation is constant time

I'm implementing Schnorr signatures following a variant used in Bitcoin Cash (BCH) of this algorithm: GitHub - Schnorr Signatures for secp256k1. A notable difference is that the BCH schnorr algorithm ...
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How does a cache timing attack work on AES with lookup tables?

I was trying to make a software only implementation of AES (Rijndael). At first I was able to implement it using table lookups for the Galois field multiplication and also for the SBox, but, I really ...
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Help on Algebraic Side Channel Attacks

I am a master student in computer security, I am preparing a dissertation thesis in the theme is: Algebraic cryptanalys by auxiliary channels, I need reference on this theme (book, thesis, ...), and ...
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Is Ed25519 really constant-time as widely implemented?

Despite the frequent claims that Ed25519 is more secure against side-channel attacks than (for instance) signatures performed over NIST P-256, I noticed that most implementations (including the ...
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Are there any masking methods for integer multiplication masking?

I'm interested in lattice type cryptosystem such as Mod-LWR. But I found that integer multiplication¹ is not safe for side-channel attacks. I tried to make masking method by own method but it failed ...
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Neural networks in Differential Power Analysis?

I am trying to understand how neural networks are used to do DPA, but I am having trouble understand DPA. My current understanding is that with DPA, we are just guessing one piece of a key at a time, ...
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142 views

Computing guessing entropy (average rank of the correct key) in attack using deep learning

I am looking for help with some issues that I have about the guessing entropy (GE) in side-channel attacks context. I have read some papers where GE is used as a metric to measure the attack's ...
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Security of bit shift in Serpent

As far I know, the Serpent cipher is the only cipher that uses legit bit shifts (<<) along with circular left shift (...
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What is TPMFail attack and what are the countermeasures?

Trusted Platform Module (TPM) is designed as a hardware-based root of trust to protect cryptographic keys even against system based adversaries. Although Intel's firmware based fTPM has FIPS 140-2 ...
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Side-channel attack in the real wold [duplicate]

I have a big problem to figure how the security model in papers about side-channel are relevant (briefly the attacker has a partial access to the hardware). Why these breaches are so seriously ...
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Side-channel vulnerability of AEGIS naive AES implementation

AEGIS, one of the finalists of CAESAR competition, uses a naive implementation of AES encryption round as its reference implementation. By naive I mean it uses secret dependent table lookups, so it is ...
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Is there a way to make a black-box function side-channel attack resistant?

If I have no knowledge of the inner workings of a function, (i.e. a black box function) is there a way to make it side-channel attack resistant? (For reference, I'm working with a JavaScript ...
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How are side-channel attacks executed? What does an attacker need to execute a side channel attack?

I've been reading about side-channel attacks on Wikipedia, and it seems that some of these can only be executed on the victim's computer. (I am specifically asking about the side-channel attacks ...
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Is encryption with the Web Cryptography API resistant against side channel attacks?

If I want to encrypt some payload with AES-GCM, with the Web Cryptography API, how resistant would this be against side channel attacks?