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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Which application protocols use elliptic curve key recovery?

Section 4.1.6 of https://www.secg.org/sec1-v2.pdf describes a technique for recovering public keys from ECDSA signatures. I guess Ethereum uses this. Like if you want to validate a particular ...
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Possible to directly calculate the Recovery ID from a msg, signature and public key in ECDSA/secp256k1?

Problem Let's say I receive a signature $(r,s)$, the corresponding public key and the message that was signed. I don't have access to the private key. I need to know what the ...
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Is it possible to generate ECDSA signature without nonce?

I am newbie to cryptography and my college has given me this ECDSA. I know that you have to divide result of: h(m)+r.priv in order to generate signature. But is it possible to generate signature ...
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Calculating random number in ECDSA based on private key and signature

In ECDSA (Elliptic Curve Digital Signature Algorithm) we use a random number $k$ in the signature process. Signature in ECDSA is: $$ (x_1,y_1) = [k]G $$ $$r = x_1 \bmod n $$ $$s = k^{-1} (z+r\,d_{a}) \...
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Avoid MITM Attack in ECDH Without HTTPS or a Third Party Certificate Authority

My context: I have a ECHD protocol, my main concern is MITM attack, it doesn't matters if you do HMAC or anything else in future to sign requests if your key exchange is compromised, Far from https ...
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Are the FIPS 186-5 and ANSI X9.142-2020 definitions of ECDSA consistent?

FIPS 186-4 Digital Signature Standard defers to ANSI X9.62-2005 for the specification of ECDSA, with additional requirements set out in Chapter 6 and Appendix D. However, X9.62-2005 has since been ...
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Is the STARK Curve a SafeCurve?

SafeCurves defines criterias for choosing safe curves in elliptic-curve cryptography. STARK Curve defines a Stark-friendly elliptic curve that can be used with ECDSA. I was wondering: Is the STARK ...
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Dsa generator verify problem

I'm trying to generate a signature for DSA with the following parameters: p=67 , q=11 , g=38 , H(m)=7 , x=6 (Is it correct to choose g=38?) I cannot choose a random k (0>k>q) that will give me r ...
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Finding an element of $\mathbb{Z}_p$ if the order of that element is known [duplicate]

I have two prime numbers $p$ (1024 bits) and $q$ (160 bits) such that $q$ divides $p-1$. Now I want to find an element $b$ in $\mathbb{Z}_p$ with the order of $q$. That means that $b^q \equiv 1 \mod p$...
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Can Montgomery ladder multiplication be used with secp256k1?

While reading about Elliptical Curves and ECDSA, I found a paper ECDSA Security in Bitcoin and Ethereum: a Research Survey by Hartwig Mayer. On page 6, the authors say: The curve secp256k1 does not ...
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Reusing additional data k' nonce from RFC6979 ECDSA

It is known that you must not reuse k in ECDSA; doing so will leak your private key. That's one of the reasons RFC6979 deterministic signatures were invented. Now, ...
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Are (EC) DSA blind signatures possible?

I've been searching for a way to create blind ECDSA signatures. My research and experimentation has led me to believe that this is not possible. I've been attempting to articulate why and I think ...
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How to get public key and bitcoin compressed address from the coordinates (x,y) generated by ECDSA?

I have my x (0xca668a8b5f71e8724aada4b5343c28702a481787855cc42228b8fff97fe94d6a) and y (0x19dd3a603a55b3d8c5f62cbe177b9b63693fb8c91d76845bafc843a7aa19ea55) coordinates generated by ecdsa with a ...
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Get the parameters of an elliptic curve's equation

I have a binary signed with ECDSA384 and I need to verify it using a particular cryptography library. The first thing that needs to be done is to initialize the EC ...
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Is there any reason to use RSA or DSA when we have ECC?

I am having trouble coming up with a use case for RSA or DSA. It appears that ECC is better in every way. Is this true? I am looking for cases where RSA/DSA is superior to ECC, not where it is used ...
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Verify that x, y coordinates given as hex string are valid points on an Elliptic Curve [duplicate]

Given the following information: "curve": "P-256", "qx": "729C51D177EBE2079A0FB7B0B3C2145159CF81EC61960E642A1744719AA9F913", "qy": "...
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How to sign CAM/DENM messages using mbed LTS libray with ECDSA (EEE Std 1609.2)

I have read ETSI TS 103 097 and EEE Std 1609.2 which gives me the security data structure defined in ASN.1 notation. I want to use mbed LTS to calculate the ECDSA signature. I understand that I should ...
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Comparison of security definitions for signatures

The two main security definitions for signatures are EUF-CMA and the strong version of it sEUF-CMA. What I see that their difference is that in EUF-CMA experiment, the adversary needs to produce a ...
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Short Nonces in ECDSA signature generation

Recently I noticed that my device generates short-sized Nonces. Approximately $2 ^ {243} - 2^{244}$. Could it turn out that there will be a small leak of ...
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Cryptography (DSA) Get Value of k and private Key

i am on a task in cryptography and need a hint (PLEASE NO SOLUTION). The Task is: I can send Messages (Digital Numbers) to a Docker Container. The response are the values p,q,g,z1,s,r and hashvalue(m+...
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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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Can I know from a Bitcoin public key if the private key is odd or even?

Can I know just from a Bitcoin public key if the private key is odd or even? [moderator note] That is, can we find parity of the private key from a secp256k1 public key?For the original dump of ...
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Complete Set of Test-Vectors for ECDSA secp256k1

Although there are several implementations of ECDSA secp256k1 public available over the internet (the most popular being OpenSSL), it seems that there are no complete set of test-vectors available. ...
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Signing same message 2 times with ECDSA

Can multiple signatures of the same message with the same private key (different nonces) lead to a private key trace?
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Is it possible (and if so how) to make one proof for multiple private keys in ECDSA

Lets say I have a message that needs to be signed by two keys that were generated using ECDSA Is it possible to make a signature that accounts for both keys, meaning I can verify with both and see ...
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Why does ECDSA produce a pair of values in its' signature (r,s)?

I was wondering why ecdsa generates a signature in form of a pair (r and s) and why it can't be only one value.
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Find the product of two sums via SMPC

I'm currently working on a distributed threshold DSA scheme that requires to find the product of two sums via secure multi-party computation. Specifically speaking, every one of $n$ parties $P_i$ ...
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Can the same public key be used for ECDH and ECDSA [duplicate]

I want to generate a public key that I can use to sign messages and receive messages (using ECDH for exemple). I want to do so to have the smallest payload to share. Is it possible and proved secure ?
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Is RSA the only current practical option for asymmetric encipherment of symmetric keys at rest?

As of 2021, is RSA the only practical (i.e. safe, production-ready) option for asymmetric encipherment of symmetric keys at rest? ECDSA is obviously preferable over RSA in the case of signing, but (...
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Chinese remainder theorem in ECDSA for parameters in secp256k1?

It is known that it is possible to apply the Chinese remainder theorem and attack RSA under precise conditions. https://tls.mbed.org/public/WSchindler-...
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Is the verification process in ECDSA the same or different from in RSA?

With an RSA key pair, from my understanding, Alice who holds the private key is able to encrypt a message into a signature. She would then send the signature together with her original message to Bob. ...
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Confusion over recovery of privatekey in DSA signature when duplicate value of r occurs

In DSA signature where signing is done via $$s = k^{-1}(H(m) + xr) \mod{q} $$ I understand why if two messages singed by the same private key $x$ use the same $k$ value you can recover the private key ...
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Why check for point-at-infinity during ECDSA verification?

The ECDSA standard mandates that during verification we check that an intermediate calculation does not lead to the point-at-infinity (see Step 5. in this summary on Wikipedia ). But why do we check ...
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Question about coefficient of ECDSA in lattice attack

Update: I made my lattice attack worked finally. As the actual reason is quite complicated I decide to write an answer below to describe how it worked so anyone with similar question might get ...
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Sentinel ("trick") values for lattice attack on DSA with biased k (MSB)

I'm studying lattice attack using this sage script. There are 2 options in script: LSB and MSB. The most interesting option for me is MSB. It recovers private key with less then 100 signatures ...
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Can deterministic ECDSA be protected against fault attacks?

In a paper by Barenghi and Pelosi, it was described that fault attacks could be used to derive the secret key when using deterministic ECDSA as described in RFC6979 by @Thomas_Pornin Deterministic (...
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Security proof about RFC 6979

In the paper: "The Random Oracle Model: a Twenty-Year Retrospective", section 7.3 by Koblitz & Menezes,the authors tried to prove the security of ECDSA+. But after looking at the entire ...
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Question about IETF RFC6979 determinisitc (EC)DSA document section 3.6 additional data k'

In RFC6979, on page 14, Section 3.6 "Variants": o. Additional data may be added to the input of HMAC, concatenated after bits2octets(H(m)): ...
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With ECDSA is there a way for the verifier to calculate any properties of $k$?

With ECDSA, given $(r,s)$ and $m$, is there a way for a verifier to calculate any (boolean) properties of $k$, without knowing $k$ or the private key $D_A$? (I understand that $k$ should be random, or ...
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Why does RFC 6979 need so many loops?

I recently started reading RFC 6979. I'm curious why it needs so many loops. This post asks a similar question: "RFC 6979 - Why not simply hash the message & the private key for deterministic ...
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Why does deterministic ECDSA (per RFC 6979) include the private key in the generation of k?

It's clear that using the private ECDSA key $x$ as an additional input into the hash algorithm, as specified in RFC 6979, doesn't harm security (assuming HMAC_DRBG is a PRF). But is it necessary? ...
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Randomization of ECDSA signing operations to prevent SCA

A large number of SCA papers that talk about ECDSA mention the need for blinding/randomisation of the signing process, typically with a single-sentence comment about replacing the projective ...
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Gennaro & Goldfeder Key Generation Protocol

As I am going through the “Fast Multiparty Threshold ECDSA with Fast Trustless Setup” paper by Gennaro & Goldfeder, 2018, I am stumbled by the key generation protocol (Sect. 4.1, p.10): In Phase ...
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Can the security of ECDSA be compromised by the chosen parameters?

The recommended parameters for a secp256k1 ECDSA curve are: (All values are in hexadecimal) ...
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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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Coin tosses in the context of commitment schemes

I was reading the “Fast Multiparty Threshold ECDSA with Fast Trustless Setup” paper by Gennaro & Goldfeder, 2018 and I encountered this portion (Sect. 2.4, p.6): This excerpt leaves me slightly ...
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Downsides of not using deterministic ECDSA signatures for blockchain validation?

I've noticed that in many Bitcoin wallet implementations, as well as other blockchains, deterministic ECDSA signatures are being used (generally based on RFC 6979). There seems to be some benefits to ...
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ECDSA Algorithm

Let the curve $$y^2 = x^3 + 3x+ 5$$ be defined on $Z_{19}$ . If my private key is $d=4$ what is my public key for $P=(9,1)$ . If $H(M)=4$, find your ECDSA signature for message. Randomize the ...
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Can $r$ and $s$ from an ECDSA signature be negative numbers?

I have an ECDSA implementation in Mathematica over secp256k1 and $r$ and $s$ are always positive numbers. But if you encode them as bytes, the most significant byte can be over ...
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ECDSA for EUF-CMA [duplicate]

If I want to prove that the ECDSA (secp256k1) on the blockchain belongs to EUF-CMA, is there any relevant knowledge or literature explaining this part?

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