Questions tagged [dsa]

The Digital Signature Algorithm (DSA) is a United States Federal Government standard or FIPS for digital signatures. It was proposed by the National Institute of Standards and Technology (NIST) in August 1991 for use in their Digital Signature Standard (DSS), specified in FIPS 186, adopted in 1993. A minor revision was issued in 1996 as FIPS 186-1. The standard was expanded further in 2000 as FIPS 186-2 and again in 2009 as FIPS 186-3.

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Software timing attack using Kocher method

What's the minimum number of random sample points needed in Kocher's timing attack, so that we can determine enough valid measurements of $A_{i,r}$ and $D_{i,r}$? I'm working from this paper: Volker ...
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What public-key encryption protocol can use the same key pair as ECDSA?

Assume we wanted to use the same ECDSA public/private key pair (drawn for standard ECC parameters, perhaps P-256) for both its intended use (public-key signature), and for public-key encryption; this ...
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How can the Number Field Sieve attack the discrete log in $\mathbb Z_p^*$ of DSA?

The Digital Signature Algorithm (DSA) uses $L$-bit prime $p$ and $N$-bit prime $q$ with $q| p-1$, i.e., $p = r\cdot q +1$ ( Schnorr group if $r>2$ and safe prime if $r=2$). In a way, the security ...
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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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469 views

Functional signatures with ECDSA Verifier

Functional signatures use some master key to create a functional signature key. The functional key can be used to sign messages, but only if the message is accepted by some predicate function. For ...
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769 views

Is Diffie-Hellman key exchange for multiple parties used in practice?

After reading this question about the possibility of using DH key exchange for multiple parties I went looking for a (C) library able to do this and found none. (I find it hard to believe there is no ...
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187 views

Cost of attack on DSA with attack on DLP

Are there any (recent) estimates of cost of attack on DSA by solving the discrete logarithm? I'm especially interested in attacks that use Pollard's rho algorithm. Are there any optimized ...
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577 views

Is this a secure (and correct) sign-then-encrypt technique for transferring messages?

After reading some information on the way iMessage works I have been working on writing some code to try my hand at securely transferring messages in a similar manner and I wanted to confirm that the ...
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612 views

Where can I find examples of ECC implemented in VHDL?

I am looking into implementing ECDSA signature and ECDH key agreement in a Xilinx FPGA. All the examples I have found of VHDL implementations skip over how to construct the low level ECC primitives (...
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Calculating ECDSA Private Key From Multiple Signatures With Shared k (random nonce)

I've been experimenting with ECDSA signatures and with how the Sony PS3 private key was leaked. Specifically where: $$k = \frac{z_1 - z_2}{s_1 - s_2}$$ $$d_A = \frac{z_1s_2 - z_2s_1}{k(s_1 - s_2)}$$ ...
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ECDSA sign test vectors

I've seen a large set of ECDSA test vectors for verification. In addition, I've seen some test vectors from NIST, and those can be found here. Is anyone aware of ECDSA sign test vectors which, if &...
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Understanding multiplication of Shamir secret sharing during threshold (EC)DSA signing

I have been looking at the threshold (EC)DSA schemes for honest majority by Gennaro et al. https://www.sciencedirect.com/science/article/pii/S0890540100928815. In the scheme, there are steps where we ...
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Zero Knowledge Proof of Association

Assuming there are a group of individuals with static ecdsa keypairs, of which the public keys are in a shared database that all of them have access to, how can each participant publish an ephemeral ...
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67 views

ECDSA - why is the first part of the signature used in the second?

Using the terminology of https://en.wikipedia.org/wiki/Elliptic_Curve_Digital_Signature_Algorithm Why is the second part of the ECDSA signature defined as: $s = k^{-1}(z+rd_A)\text{ mod n}$ ...
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293 views

ECDSA Message Recovery from Two Encrypted Messages with Signatures and Public Key

I am currently working on a problem where I have two encrypted messages, their corresponding signatures, and the public key. Furthermore, the value of $r$ is the same in the two signatures. I am ...
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999 views

Diffie-Hellman combined with DSA/RSA

we have learned Diffie-Hellman, RSA and DSA (Digital Signature Algorithm) in university. Because DH is vulnerable of Man-in-the-Middle we had the task to program the DH combined with RSA to protect ...
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89 views

Does it make any sense to hash parts of a hashing target?

TL;DR; Assuming I'm calculating SHA256 for an ECDSA, does it make sense to do SHA256(item1 + SHA256(item1') + item2 + SHA256(item2') + itemN + SHA256(itemN')) or it'...
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Which signature is considered more secure and has less communication cost?

This article uses Elliptic Curve Cryptography, but when it comes to signing and verifying messages it is not using the ECDSA signature algorithm. In the article, they mentioned that the communication ...
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Is this a good implementation of digital signature with timestamp?

Is this a good practice ?. How good or bad is this compared to appending a timestamp to the actual data and hashing it as represented below. ...
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42 views

Vulnerability in the Digital Signature Algorithm. Can I calculate k and x?

I feel DSA is vulnerable if k is randomly selected over a small set, example, {1,2,...,2^16 -1}. I am trying to come up with a program where I assume I have the public parameters (p,q,g) , public key :...
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47 views

how to efficiently compute private key in DSA with known parameters

For textbook DSA, as defined below. If $r, s, k, g, p, q, m$ are all known, is it possible to efficiently compute $x$ from all these given values? How does the math work out? Secret key: $x\stackrel ...
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Cryptanalytic tests for biased nonces

In the paper Biased Nonce Sense: Lattice Attacks against Weak ECDSA Signatures in Cryptocurrencies on section 5.2 Cryptanalytic tests for biased nonces, one of test is: Select two signatures at ...
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Bitcoin ECDSA signature

I am trying to use the ecdsaSign function in ecdsa.c of https://github.com/kvhnuke/Ethereum-Arduino/tree/master/Ethereum-Arduino/libs which is based on the files in the repo https://github.com/...
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Signing a secret key with ECDSA

Assume Alice and Bob both separately come into possession of the same randomly generated 256 bit secret key. Alice has Bob's public ECDSA key. Alice wants to verify that Bob has possession of the ...
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Complexity upper bound MFC DSA with linear S-Box

in advance, excuse my eventuelly bad english. It's not my mother tongue. I work on a coolege Computer Science Project. For this, i need to know the upper bound of the complexity for the MFC( Formal ...
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Comparisons of ECDSA, EdDSA and BLS Signatures in Blockchain: Pros and Cons

As we know, the most used digital scheme in Blockchain is ECDSA. For now, more and more blockchain projects, I've noticed, are considering substituting EdDSA and BLS signature scheme as the new one. ...