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Questions tagged [elliptic-curve]

In mathematics, an elliptic curve is a smooth, projective algebraic curve of genus one, on which there is a specified point O.

In mathematics, an elliptic curve is a smooth, projective algebraic curve of genus one, on which there is a specified point O (the point at infinity). An elliptic curve is in fact an abelian variety — that is, it is a (necessarily commutative) group with respect to an algebraically defined multiplication — and O serves as the identity element. Often the curve itself, without O specified, is called an elliptic curve.

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SAGE - 'NoneType' error on valid Sage syntax

I'm trying to write a program to calculate a generator point of an elliptic curve in sage. The function to do this is is: E.gen(0) Where E is some Elliptic Curve. If I do this on the online version of Sage it works without issue: sage: E =…
user2059300
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ECKeyAgreement in Generating public and private key using ecc

I am working on a concept of encryption and decryption using ecc. I already generated public and private key. While I am encrypting the text I am getting this error: java.security.InvalidKeyException: ECKeyAgreement requires ECPrivateKey at…
vijay kumar
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Using ECDSA instead of RSA for encrypting and decrypting integer

I want to use ECDSA instead of RSA for encrypting and decrypting integer number. Ususally ECDSA is used for digital signature. But it's possible to transform algorthm of digital signature: use signature generation for decryption, signature…
mayflower
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ed25519 ECDH encryption possible and safe?

As far as I can see everybody use curve25519 for public/private encryption (ECDH) and ed25519 for signing (ECDSA). This creates double size of keys or some special conversion tricks that may not be safe: https://github.com/dchest/ed2curve-js Is it…
Beast
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Encryption and Decryption with El-Gamal Elliptic Curve

I was look around the answer and googling to find a way how to encrypt and decrypt a string with El-Gamal Elliptic Curve without any third party library but there's always the answer to use a third party library like bo*...castle or fle**provider.…
Rhony
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Inversion and point subtraction on Elliptic Curve

I'm trying to implement an authentication protocol based on elliptic curve over prime field in Matlab. I have already done the point addition and point multiplication successfully, but I'm facing a problem while computing the following…
Missa
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magma computer algebra system local and global variables

function Max(x) max := 0; L := []; for i := 1 to x do P2 := ProjectiveSpace(Rationals(),2); C_i := Curve(P2, x^3+y^3-i*z^3); E_i, C_itoE_i := EllipticCurve(C_i); gen := Generators(E_i); if max…
Adam Staples
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node.js Wallet Import Format (WIF) for Hierarchical Key in BitCore

I am trying to generate WIF from extendedprivatekey, but i am getting invalid WIF. How should WIF look : https://bitcoin.org/en/developer-guide#wallet-import-format-wif I've followed instructions from above link and got this code: var crypto =…
klonodo
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ECC point multiplication algorithm

I've been working on implementing ECDH into my iOS project and have a small logic bug in my code for the point multiplication. From testing with the NIST List examples ("Link") I know that my double method and my add method is working correctly…
user3207681
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ECDSA on Java BouncyCastle always returns true

I have an android program that writes data and signs ECDSA to NFC Tag, and another program that reads that data and verifies the signature from the NFC Tag. I managed to write and sign the data to the NFC Tag, but whenever I try to verify the…
RedCrimson
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How represent message for Elgamal EC?

I am working on my project that uses elgamal elliptic curve. I know when the elgamal ec encrypt by following steps Represent the message m as a point M in E(Fp). Select k ∈R [1,n−1]. Compute C1 = kP. Compute C2 = M +kQ. Return(C1,C2). Where Q is…
MHS
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Koblitz method in Java

I'm trying to use Koblitz's method to convert String to ECPoint, Eclipse says that there are no errors in my code, but when I try to run my application, it gets an error everytime the code gets to the Koblitz method. Sorry, I know this kind of…
RedCrimson
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Point division Elliptic Curve in Java

Suppose I have G(x,y) = k.P(x,y). I know G(x,y) and P(x,y). How do I calculate k?
RedCrimson
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Can't run Curve25519 implementation on Android device - able to on PC

I am trying to port a Java implementation of a authentication mechanism that uses Curve25519. The libraries work perfect on my PC. But when I run it on an android device - I get a stackoverflow. The Curve25519 implementation does have a lot of…
rtindru
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Elliptic Curve Cryptography : sending an encrypted message using NFC in eclipse android

I'm currently working on an ECC project. So the project goes like this, I want to send an encrypted message from my android phone using NFC to a contactless smart card. The tag is being developed by a different team, so that's not the problem…
RedCrimson
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