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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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Security of Fast Two-Party ECDSA Signing

The paper "Fast Secure Two-Party ECDSA Signing" by Yehuda Lindell describes a system in which two parties, $P_1$ (with 1/2 of a share of a long-term ECDSA signing key $x_1$) and $P_2$ (with the other ...
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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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Can a TLS certificate using ECC secp384r1 as PK algorithm uses RSA for signature

If a TLS certificate public-key algorithm is ECC secp384r1 or ECC prime256v1, is it possible to have RSA as a signature ...
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What is the recommended minimum key length for ECDSA signature

I want to identify the proportion of certificates that use unrecommend ECDSA key length for TLS certificates based on some data I collected. By looking at a standard like NIST for example, I find ...
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Exactly what RNG weaknesses endanger (EC)DSA?

RFC 6979 defines deterministic variants of (EC)DSA. It states in introduction One characteristic of DSA and ECDSA is that they need to produce, for each signature generation, a fresh random ...
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DSA signature creation using hash oh the message

I am trying to understand how i can create DSA signature. the arithmetic uses H(M) and it is given a random nunber for the hashing result.( written- lets assume it is 121). Is the number really random ...
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37 views

openSSL and ECDSA key format inspection

If I run openssl ec on a key that I have generated with openssl ecparam -genkey I get one extra prefixing 0x00 in the private ...
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81 views

Why ECDSA has its form?

According to Wikipedia, if Alice wants to sign some message, she computes $s = k^{-1} (z + r d_A)$ then sends $(r, s)$ to Bob. I don't understand why they use this particular formula $s = k^{-1} (z + ...
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DSA signature generation [duplicate]

I am trying to implement given DSA signature generation instructions in python, there are few instructions that I couldn't understand in step 3 and 4. Let m be an arbitrary length message. The ...
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66 views

DSA: How to calculate 224-bit $q$ for 2048-bit $p$

$p$ is a 2048 bit prime number $q$ is a 224 bit prime number I know that $q$ is a prime divisor of $p-1$, thus $p=1 \bmod q$ but I couldn't write efficient code to calculate this. I can calculate ...
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ECDSA Signing and verifying signatures between Python and JS [closed]

I create a signature on js, here jsrsasign Signatures are obtained in the format: ...
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64 views

Why don't the TLS1.3 cipher suites mention the key exchange and digital signature algorithm in names?

Does it mean both RSA and ECDSA certificates can be used with the same cipher suite?
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ECDSA with common nounce?

I'm new to cryptography, and I've searching about ECDSA because I'm trying to solve a CTF. I've already check this site and Google, and I think I'm in the right path, but probably I am missing ...
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Regarding Lattice atttacks on ECDSA with a portion of known bits of the nonce k

I am new in the field of cryptography, and I am having some troubles understanding a concept regarding the lattice dimension needed in the attack on ECDSA using several messages with L known bits of ...
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Encrypt your ECDSA signature with NTRU to make them quantum secure, does that work?

I have a general question about quantum security. ECDSA is suppose to be broken by quantum computers. Whilst something like NTRU is suppose to be secure. My question is: if we sign with ECDSA and ...
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Linkable ECDSA like signature

In our process of digital checks for banking - which needs to work online and offline - the receiver needs to know the chain of all generated signatures without consulting an Internet service. In this ...
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ecdsa where the group order is larger than the hash size?

According to wikipedia, when generating a signature for ECDSA, you do the following (among other things): Calculate $e=HASH(m)$, where $HASH$ is a cryptographic hash function, such as SHA-2. ...
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How to prove two ECDSA public keys on two different curves are generated from the same private key [duplicate]

I wonder if I provide someone with two public keys from different elliptic curves, is there any way to prove that these two public keys are generated from the same private key without revealing the ...
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Why can we not use the group $Z_{p}^{*}$ for cryptography?

Sorry if this is a noob question, but for instance in ECDSA, we start by considering the field $\mathbb F_p$, whose the elements also form a group under multiplication. Why don't we just use this ...
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Calculating $K,N,X$ in ECDSA?

I'm confused with the parameter $n$, whether the parameter $n$ is the support point FFFFFFFF FFFFFFFF FFFFFFFF FFFFFFFF FFFFFFFF FFFFFFFF FFFFFFFE FFFFFC2F or what? ...
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1answer
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Can root and intermediate CAs use different asymmetric ciphers and key sizes?

For example, could a root CA use RSA-4096, one intermediate CA use RSA-2048, and another use ECDSA-256 (DH19)?
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Offline authenticated encryption for pub/sub

Requirements: only publisher can create messages publisher & subscriber can both read messages and authenticate the publisher offline message transfer messages can't be read by non-participants ...
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Atomic multi-party commitments

Alice and Bob publicly choose the messages $M_A$ and $M_B$ and independently sign them (Alice privately signs $M_A$, Bob signs $M_B$). Now Alice and Bob are looking for a protocol that allows them to:...
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Known risks for publishing ECDSA public keys and signatures

For an implementation of ECDSA, I'm considering the risks of publishing public keys together with multiple signatures. From what Google tells me, a common pitfall is the use of the same random value ...
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2answers
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Max size for exponent and modulus in RSA and for y, p, q, g in DSS

I'm writing a method in Java to read SSH public key in RFC 4253 format, which, in my case, can be either RSA, or DSS. What I really need is to read exponent and <...
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1answer
81 views

Appending ECDSA signature to a message

I need to authenticate a message sent to an embedded device (which limits my options in terms of just using an existing convention). I can run ECDH/ECDSA on the device and can use SHA-256 as a hash ...
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Point multiplication over Fp

I have a decent grasp on how point multiplication works in the context of the regular elliptic curve, however once we limit to whole numbers over a finite field I get confused. How on the world do we ...
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What does ChopMD refer to in the default Go ECDSA package?

If one navigates to the ECDSA Go package page, he can observe that: This implementation derives the nonce from an AES-CTR CSPRNG keyed by ChopMD(256, SHA2-512(priv.D || entropy || hash)) While I ...
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ECIES: ECDSA with Kmac and without MAC

I have couple of questions about ECIES. I understand how ECIES work and what I must do if I want to have ECIES with ECDSA for authentication (I understand that for full authentication I have to have ...
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ECIES with ECDSA

I understand how ECIES work. I have a structure of message [alice`s ephemeral public key, MAC tag, ciphertext] I do not understand what I shoud do if I want to ...
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1answer
63 views

Can ECDSA key pairs be added up or multiplied?

I have been given a public key ($y_1=x_1G$), but I don't yet know the private key ($x_1$). At a later time, I will get $x_1$ if some conditions are met. Question: Let's say I generate a new key pair ...
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402 views

What is the difference between ECDSA and EdDSA

As I understand it, both work with elliptic curves but there seems to be a difference as EdDSA is generally recommended over ECDSA.
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DSA Vulnerability in ECDSA

I have implemented a ruby code where i generate private and public keys as below. However, I read few articles [1] on DSA and why it should not be used. I'm not good at cryptography. But still ...
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Why does ECDSA transmit s and not s^-1? [duplicate]

Given: $eG=P$, $kG=(r,y)$ ECDSA signature transmits (r,s) and does this calculation: $u = \frac{z}{s}$, $v = \frac{r}{s}$ $uG+vP=(r,y)$ means the signature is valid Why do we transmit $s$ and not ...
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Private key ECDSA/TLS

Is the private key required once the certificate is hashed and signed? After a certificate is generated, public key is shared within the certificate itself. Is the private key used for any other ...
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In ECDSA, why are u and v dividing by s?

The verification algorithm for ECDSA is: $P=e\times G$, $(r,y)=k\times G$, and $s=(z+re)\times k^{-1} \bmod n$, where $P$ is the public curve point, $G$ is the generator point, $e$ is the ...
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How fast a middle-class computer can verify assymetric signatures (like ECDSA, RSA etc.)?

I have an idea for a peer-to-peer network that will require every connected peer to verify many symmetric signatures per second. In bitcoin, it's the same - every peer independently verifies ...
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What is the difference between: ecdsap, ecdsak, and ecdsab in the output of “openssl speed”? What do the letters P/K/B refer to?

openssl speed tests the speed of different protocols on your computer: ...
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ECDSA vulnerability related to recovering private key using same r

I'm considering this for bitcoin transaction as it uses ECDSA so if the signer generates two signatures suppose s1 and s2. where: I get it that any attacker who have s1 and s2 can recover its private ...
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Could RSA keypairs be used for cryptocurrency addresses?

A bitcoin address is created from an ECDSA keypair. It is common to use use a hashed version of the public key as the shared address, but the original bitcoin implementation also allowed for using the ...
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ECDSA recover on arbitrary values

If I were to supply arbitrary values to an ECDSA recover function on secp256k1, is there some likelihood that the function would fail to return some value for the public key? I am specifically trying ...
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A method for creating distributed public key for ECDSA, what are the risk factors?

There is quite a bit of literature on distributed ECC signing without a trusted dealer. Published works are mostly overly complicated, so I am proposing this simple technique which I am sure if it is ...
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1answer
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Which hash function to be used with DSA 2048

I'm preparing for an examination of an Information Security course at university, but I'm not sure about an explanation I created for a specific exercise. The question is: There are now DSA ...
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What is the maximum message size when using ECDSA (specifically secp256k1?

I'm guessing that the message must conform to 256 bits but I was not able to find documentation of any message length limits.
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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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Are ECDSA keys and RSA keys interchangeable?

Is it possible to use an ES512 key pair for RS512 signatures? Is it possible to use an RS512 key pair for ES512 signatures? I've also posted an issue in the NodeJS jwa package. I created a key pair ...
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decoding a Ed25519 key per RFC8032

RFC8032 Edwards-Curve Digital Signature Algorithm (EdDSA) 5.1.3 Decoding states the following: Decoding a point, given as a 32-octet string, is a little more complicated. First, interpret ...
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Is there a truly safe signing algorithm?

After reading this question, I'm pretty shaken up. A determined attacker with $100 in loose change can crack any RSA key in a couple of hours. After believing that these algorithms would take millions ...
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ECDSA, EdDSA and ed25519 relationship / compatibility

I'm trying to understand the relationship between those three signature schemes (ECDSA, EdDSA and ed25519) and mainly, to what degree are they mutually compatible in the sense of key pair derivation, ...
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Which one is better using DSA, or MAC and encryption?

I want to authenticate server messages to clients. The communication between clients and server is unicast. As I know I can use either used MAC or DSA. by using MAC, I required a shared key between ...