Knowledge Base
Diffie-Hellman Parameter
D

8192-bit MODP Group/Oakley Group 18 (RFC 3526)

Summary

Name:
8192-bit MODP Group/Oakley Group 18 (RFC 3526)
Key size:
8192 bits
Publishers:

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Security

D
Key Size
Name

8192

Security

The Diffie-Hellman ephemeral public key parameter[409][410][411] with a prime size greater than 4096[590] is considered secure but weakened against the D(HE)at attack[581][582][583][584], which is a denial-of-service attack[585][586][587][588][589] against the Ephemeral Diffie-Hellman[405][406][407][408] key exchange[133].

Recommendations

Use a well-known Diffie-Hellman ephemeral public key parameter[426][427][428], or generate a custom Diffie-Hellman ephemeral public key parameter[409][410][411] with a size greater or equal than 2048 bits but less or equal than 4096 bits. In the case of custom parameters, validate that the prime is a safe prime[176] to avoid a small subgroup confinement attack[72][73].

A+
Prime
Name

Safe Prime

Security

Diffie-Hellman ephemeral public key parameter[409][410][411] contains a safe prime[176], so the connection is certainly not vulnerable to a small subgroup confinement attack[72][73].

A
Post-Quantum
Name

False

Security

The Diffie-Hellman[99][100][101][102][103] key exchange provides no protection against a cryptanalytic attack by a quantum computer, and no classical Diffie-Hellman does — just as no classical elliptic curve does — 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)
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Generator (g)
0x2
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Representations

PEM

Default private value length
-----BEGIN DH PARAMETERS-----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-----END DH PARAMETERS-----
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Small private value length
-----BEGIN DH PARAMETERS-----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-----END DH PARAMETERS-----
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PARI/GP

powermod(x, k, m) = lift(Mod(x, m) ^ k);

g = 0x2;
p = 2^8192 - 2^8128 - 1 + 2^64 * (floor(2^8062 * Pi) + 4743158);
s = 256;

a = 2 ^ (s - 1) + random(2 ^ (s - 1));
A = powermod(g, a, p);

b = 2 ^ (s - 1) + random(2 ^ (s - 1));
B = powermod(g, b, p);

S = powermod(B, a, p);
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LaTeX

$\begin{eqnarray}
p \equiv 2^{8192} - 2^{8128} - 1 + 2^{64} * (\lfloor 2^{8062} * \pi \rfloor + 4743158) \\
g \equiv 0x2 \\
\\
a \in \mathbb{Z}_q \\
b \in \mathbb{Z}_q \\
\\
A \equiv g^a \pmod{p} \\
B \equiv g^b \pmod{p} \\
\\
S \equiv {(g^{a})}^{b}={(g^{b})}^{a}=g^{ab} \pmod{p}
\end{eqnarray}$
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