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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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Working with Public Key generated from Java (using bouncy castle)

I am trying to use Python to work with peer public key generated from Java (uses BouncyCastle.) Here is the snippet from the Java Code. It uses ECDH and Curve25519. KeyPairGenerator keyPairGenerator = KeyPairGenerator.getInstance( …
Ajeet2040
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get ecc public key from x and y components in PEM format using openssl

Can I get the ecc public key from x and y components in PEM format using openssl? X: 1d 43 15 e3 84 99 d6 f6 9f 49 61 8a ae ec f2 4f Y: b5 1a 86 cf f9 0e 01 af 3a 9a 52 b3 c6 58 2c 48 thank you!!!!!!!!!!!
aiden.yang
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Computing the cardinality of an elliptic curve group over the finite field

My objective is to get the number of points on a curve over Fp with prime p being at least 160 bit and then print it out into a textBox in Winform. y^2= x^3 + Ax + B mod p After some research, I stumbled upon SageMath, which I have downloaded…
Tuan Minh Luu Dat
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Getting the EC curve of a EC public key in CNG

I have a Public key in CNG (BCRYPT_KEY_HANDLE), and I need to know the curve it uses. I tried BCryptGetProperty with BCRYPT_ALGORITHM_NAME parameter, but it only gives ECDH_P256 back, not the exact curve type. I need to know if its prime256v1 or…
Zsolt Czikó
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How to calculate p256Zero31 in NIST P256 golang implementation?

We found there are predefined // p256Zero31 is 0 mod p. var p256Zero31 = [p256Limbs]uint32{two31m3, two30m2, two31m2, two30p13m2, two31m2, two30m2, two31p24m2, two30m27m2, two31m2} in crypto/elliptic/p256.go. p224.go has similar var p224ZeroModP31.…
Emman Sun
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How to decompress X9.62 coordinate

I am passing a byte[] to my method and I am trying to generate a pubKey. Looking at the error look's like i first need to decompress before generating pubKey. How can I decode a compressed coordinate ? private static PublicKey…
user2748161
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How to use XOR operator on two elliptic curve points in java?

Im trying to implement mutual authentication between server and tag using Elliptic Curve Cryptography. I found already prepared algorithm and now Im trying to implement it in Java. I stucked on calculating authentication parameter as: A = R (XOR) X…
Gosia
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Mapping problem of PKCS11 EC public key to BC PKCS10 object

I have created EC key pair in HSM using PKCS11Interop library, and i need to create PKCS10 Certificate request using this keys. For generation of PKCS10 I use BC, and in this situation i need to set public key as a parameter for PKCS10 request. In…
Uzeyir
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Elliptic Curve Point Addition and Multiplication in Crypto++

How to use the point addition and multiplication functions in elliptic curve using Crypto++ library? I've tried the following code where Basepoint and point are the points on the elliptic curve. const ECP::Point& ECP::Add(&Basepoint,…
user11543755
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Own random (not the private key) in the ECDSA

I'm trying to debug my own implementation of the ECDSA signature. To compare the intermediate results I would like to force the OpenSSL, Crypto++ or whatever else package to use a known "random" number instead of generating it each time the…
Vic
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Why P-521 public key X,Y some time is 65 bytes some time is 66 bytes

I use golang generate the P-521 public key. source code look like that: curve:=elliptic.P521() priv, x, y, err := elliptic.GenerateKey(curve, rand.Reader) xBytes:=x.Bytes() yBytes:=y.bytes() //len(xBytes) some time is 65 bytes ,some time is 66…
user9235725
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How to calculate a private key from public key on elliptic curve?

Provided, that you have to multiply a well known G by the private key to obtain the public key, why not keep adding G to itself until you reach the public key. The private key should be the number of times you've added the G to itself. Is it…
Matthias Danetzky
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C ECC Double-And-Add

I am currently working on C code for Elliptic Curve Crypto using the Double-And-Add algorithm. I am facing a seg fault problem which I don't understand. I hope someone of you might have an idea. #include "lib/include/gmp.h" #include…
Donut
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Encryption and Decryption of text messages using Elliptic Curve Cryptography Separately

I have this code which encrypts and decrypts text messages using Elliptic curve cryptography simultaneously. I divide split the code into two parts: encryption and decryption. But during decryption I get errors. Can someone resolve those for…
Rajkeen
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How to calculate key size of a security algorithm?

There are lots of security algorithms. One of the way to measure security of a cryptography algorithm is to find out its key size. There are many key size of a single algorithm. ECC (Elliptic Curve Cryptography) has 163, 256, 384, 512 etc. RSA has…
Md. Nasir Uddin Bhuiyan
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