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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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Use of ECC in Java SE 1.7

I am trying to run the code in this pdf. For example, for ECCKeyGeneration, I get the following output instead of Figure 1 in the pdf: sun.security.ec.ECPrivateKeyImpl@58b6 Sun EC public key, 192 bits public x coord:…
Mehmed
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How to determine whether EC Point is on curve?

I have an ECPoint object "pointW" that I would like to check for whether it actually lies on some EllipticCurve "curve". How can I do this? I would prefer a solution using Java Crypto API but Bouncy Castle would also be fine. Thank you!
Thomas Lieven
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How to find minimum y coordinate for elliptical curve y^2 = x^3 +

How can I find the minimum y coordinate for elliptical curve y^2 = x^3 + ax + b on a finite field F(p) in SAGE where a and b are large about the order of 10^15 and the integer p is very large about the order of 10^45 ? I need to find it in SAGE and…
user3567036
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Koblitz's Method in Elliptic Curve Cryptography using Java

I am trying to convert a string to ECPoint using Koblitz's method. The method stated that: 1. Say we have to send a character 'b' 2. 'b' is first encoded as number 11 3. Choose an auxiliary base parameter, for example k=20 4. For each number mk,…
RedCrimson
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Why is the ECC-DH Symmetric Key Of This Site Different From OpenSSL

I am using (this site's) Javascript library and OpenSSL Ruby to compute the symmetric key of Elliptic Curve Diffie Hellman. However, from my results, OpenSSL Ruby only generated one key unlike that on the site which has X and Y symmetric keys. I am…
Jay-Ar Polidario
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Get standard, printable public-key string for ECDSA

I'm looking to be able to generate the same kind of public-key string that you'd get from "ssh-keygen -t ecdsa". I have an EC_KEY. I tried using: PEM_write_bio_EC_PUBKEY(bio_out, ecdsa); ...But I get a string that's entirely too large. I tried…
Dustin Oprea
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BouncyCastle ESDSA implementation

I'm implementing ECDSA in C# using the BouncyCastle library and I'm having a hard time understanding TestECDsa192bitPrime() example. FpCurve curve = new FpCurve( new BigInteger( "6277101735386680763835789423207666416083908700390324961279"), //…
user3160055
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How can I recover compressed y value from sender?

I am working on following scenario: Generate private and public key Generate compressed public key with: PublicKey.AccessGroupParameters().SetPointCompression(true) Sign some data and send to other end with compressed public key. [At other end]…
Felixr3136148
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Pari/GP Exceptions/break loops

ellpow(E, P, m) will always throw an exception: *** ellpow: impossible inverse modulo: Mod(x, y). *** Break loop: type 'break' to go back to GP where x and y are integers. I want to trap the value x, without finishing the program in order to use…
gon1332
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How to handle short hash with longer order of base point in ECDSA

I am using CVC certificates (If you haven't heard about them, pretend they are X509) with Elliptic curve signature with brainpool256r1 curve and SHA1 hash. In java with bouncycastle, I simply verify them like this: Signature sign =…
Petr
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Scalar Multiplication for elliptic curve over Prime Field

I am trying to implement a scalar multiplication over a prime field for P192r1. Point addition works fine by using the code borrowed from java Scalar Multiplication But concerning Point doubling where I used Code again from that link, it does not…
student
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Invalid key exception when doing elliptical curve cryptography

I got this error when I did elliptical curve cryptography using flexyprovider. I received an InvalidKeyException but I can't figure out how to solve it: Exception in thread "main" java.security.InvalidKeyException: Illegal key size at…
Shakeeb Manjeri
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ECDHE Security with Bouncy Castle

I am quite new and unexperienced in the field of Elliptic Curve cryptography. After some research I have determined unlike traditional DHE, ECDHE parameters should not be generated but rather chosen from a list of pre-defined curves (examples…
initramfs
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Given an public key of type CKK_EC, is it possible to find the matching private key using C_FindObjects?

I have a serialized EC public key - its CKA_EC_PARAMS and CKA_EC_POINT. There's a matching private key on my token. Is there any way to find it? With an RSA key, I can do a FindObjects with CKA_KEY_TYPE=CKK_PRIVATE_KEY and CKA_MODULUS=. Is…
Mark Wright
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ECC key encoding in pyecc and seccure

I am working with pyecc which uses the seccure C library. When a public key is generated I get something back like this: #Gp}7RRWK5Dyg&-m5yHve1p{?
Ihmahr
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