Knowledge Base
Elliptic-Curve Parameter
A

prime239v2

Summary

Name:
prime239v2
Long Name:
prime239v2 elliptic curve (239-bit prime field)
Key size:
239 bits
Object identifier:
1.2.840.10045.3.1.5
Publishers:

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Security

A+
Key Size
Security

The elliptic-curve cryptography[118][119][120][121] is an approach to public-key cryptography[164][165][166] based on the elliptic curve[116][117]s. The most important property in terms of encryption strength, beyond the designer is elliptic curve key size[292][293][294]. All the key sizes available are considered secure, so there is no consideration about it.

A
Trusted Design
Security

The elliptic-curve cryptography[118][119][120][121] is an approach to public-key cryptography[164][165][166] based on the elliptic curve[116][117]s. Note that there is controversy[287][288][289][290][291] around some of the National Institute of Standards and Technology[470][471] designed elliptic curveselliptic curves designed by NIST[285][286].

Recommendations

Add at least one elliptic curve to the list of elliptic curves supported by your server designed by independent researchers and prefer them as server configuration makes it possible.

A
Post-Quantum
Security

The elliptic curve[116][117] cryptography provides no protection against a cryptanalytic attack by a quantum computer, and no classical elliptic curve does — just as classical Diffie-Hellman does not — because a quantum computer breaks the hardness assumption they rely on. Only a hybrid key exchange (a classical algorithm combined with a post-quantum cryptography[158][159] one) or a pure post-quantum algorithm is quantum-safe.

Recommendations

Enable a hybrid key exchange or a pure post-quantum algorithm on your server, and prefer it where the configuration allows, so the connection stays secure against a future quantum computer.

Parameter Numbers

Prime (p)
0x7fffffffffffffffffffffff7fffffffffff8000000000007fffffffffff
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Coefficient (a)
0x7fffffffffffffffffffffff7fffffffffff8000000000007ffffffffffc
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Coefficient (b)
0x617fab6832576cbbfed50d99f0249c3fee58b94ba0038c7ae84c8c832f2c
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Generator (x)
0x38af09d98727705120c921bb5e9e26296a3cdcf2f35757a0eafd87b830e7
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Generator (y)
0x5b0125e4dbea0ec7206da0fc01d9b081329fb555de6ef460237dff8be4ba
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Order (n)
0x7fffffffffffffffffffffff800000cfa7e8594377d414c03821bc582063
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Cofactor (h)
0x1
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Representations

PEM

-----BEGIN EC PARAMETERS-----
BggqhkjOPQMBBQ==
-----END EC PARAMETERS-----
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PARI/GP

p = 0x7fffffffffffffffffffffff7fffffffffff8000000000007fffffffffff;
a = 0x7fffffffffffffffffffffff7fffffffffff8000000000007ffffffffffc;
b = 0x617fab6832576cbbfed50d99f0249c3fee58b94ba0038c7ae84c8c832f2c;
E = ellinit([a, b], p);
G = [0x38af09d98727705120c921bb5e9e26296a3cdcf2f35757a0eafd87b830e7, 0x5b0125e4dbea0ec7206da0fc01d9b081329fb555de6ef460237dff8be4ba];
n = 0x7fffffffffffffffffffffff800000cfa7e8594377d414c03821bc582063;
h = 0x1;
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LaTeX

$\begin{aligned}
y^2 &\equiv x^3 + a x + b \pmod{p} \\
p &= 0x7fffffffffffffffffffffff7fffffffffff8000000000007fffffffffff \\
a &= 0x7fffffffffffffffffffffff7fffffffffff8000000000007ffffffffffc \\
b &= 0x617fab6832576cbbfed50d99f0249c3fee58b94ba0038c7ae84c8c832f2c \\
G &= (0x38af09d98727705120c921bb5e9e26296a3cdcf2f35757a0eafd87b830e7, 0x5b0125e4dbea0ec7206da0fc01d9b081329fb555de6ef460237dff8be4ba) \\
n &= 0x7fffffffffffffffffffffff800000cfa7e8594377d414c03821bc582063 \\
h &= 0x1
\end{aligned}$
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