Tagged Questions
3
votes
1answer
89 views
Why doesn't this replay attack work on ECDSA?
I've just started working with elliptic curves and ECSDA in particular, so my understanding of the underlying math isn't great. The thing I'm currently stuck on is trying to understand why replay ...
1
vote
1answer
147 views
Is there a method to break an EC curve for all key-pairs (Q,d) such that (Q=d*G) faster than breaking every single key-pair?
Related to this question: Is there any memory trade-off that helps such attack?
Obviously if the field size is very small (say 40 bits) it´s possible, but what if the field size is 160 bits long? or ...
1
vote
1answer
179 views
Storage of Private Keys
I'm building a bitcoin web application that will require all users to be assigned a wallet for adding funds to their account. I plan on exposing the public key to the user (the bitcoin address). Users ...
7
votes
2answers
314 views
Using same keypair for Diffie-Hellman and signing
Are there any security risks using a single key-pair for both key-exchange and signing?
I'm mainly interested in using Curve25519 for key-exchange and Ed25519 for signing. But similar combinations, ...
1
vote
1answer
153 views
How to properly add ECDSA private keys?
I'm currently working on an application that requires me to add two ECDSA private keys in order to make a new private key. The result has to have the property, that its corresponding public key is the ...
0
votes
1answer
118 views
ECDSA - point order criterion
i am creating some primitive demostration for ECDSA over small curve ( p < 229). But my implementation have some weird issues. Verify process return false even if the signature is correct. Because ...
3
votes
1answer
290 views
Elliptic curves for ECDSA
i'm trying to implement parameters generation for ECDSA according to SEC1 v2.0:
Input: The approximate security level in bits = t is {80, 112, 128, 192, 256}
...
4
votes
1answer
1k views
How strong is the ECDSA algorithm?
Some cryptographic algorithms are as strong as the size of their key is, while other have some weaknesses that limit their strength (such as SHA-1). How strong is the ECDSA algorithm, and does that ...
3
votes
0answers
339 views
Elliptic curve cryptography related key attacks
This question is an extension of Families of public/private keys in elliptic curve cryptography
As described above, bitcoin "type 2" deterministic wallets use a root private/public key pair, where ...
6
votes
2answers
489 views
Can one reduce the size of ECDSA-like signatures?
Using $n$-bit ECDSA, a signature has a size of $2·n$. It is possible to recover the public key from this signature, which shows that there is a publicly visible redundancy in the signature.
Is ...
3
votes
1answer
450 views
X9.62 Multiplying an elliptic curve point by a number
I'm currently trying to implement ecdsa and the first problem i met -- multiply an elliptic curve point by a number.
As far as i understand X9.62 gives some recommendation for doing it but i ...
6
votes
3answers
512 views
Can ECDSA signatures be safely made “deterministic”?
Using the terminology of the ECDSA wikipedia page, ECDSA (and DSA) signatures require a random k value for each signature which ensures that the signature is different each time even if the message ...
5
votes
1answer
132 views
How can I use Weierstrass curve operations with a=-3 for implementing operations for a=0?
I am working with golang's elliptic library.
It implements functions on Weierstrass elliptic curves with $a=-3$. I need to make my own library that allows me to handle curves with $a=0$. I understand ...
6
votes
1answer
520 views
Secp256k1 test examples
Are there any available test cases for testing elliptic curves like secp256k1 (Korblitz curves from http://www.secg.org/collateral/sec2_final.pdf)? For curves like P192 there are for example those ...
