A fast Diffie-Hellman key exchange algorithm
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$ dotnet add package BlufiDHReadme
BlufiDH
A fast Diffie-Hellman key exchange algorithm in .NET Standard 1.1 and .NET 6.
Example
const string DH_P = "cf5cf5c38419a724957ff5dd323b9c45c3cdd261eb740f69aa94b8bb1a5c9640" +
"9153bd76b24222d03274e4725a5406092e9e82e9135c643cae98132b0d95f7d6" +
"5347c68afc1e677da90e51bbab5f5cf429c291b4ba39c6b2dc5e8c7231e46aa7" +
"728e87664532cdf547be20c9a3fa8342be6e34371a27c06f7dc0edddd2f86373";
const string DH_G = "2";
const int radix = 16;
const int dhLength = 1024;
BigInteger dhG = BigInteger.Parse(DH_G);
BigInteger dhP = RadixBigInteger.Parse(DH_P, radix);
BlufiDH appDH = new(dhG, dhP, dhLength);
BlufiDH espDH = new(dhG, dhP, dhLength);
BigInteger A = appDH.GetPublicKey();
BigInteger B = espDH.GetPublicKey();
BigInteger keyA = appDH.GenerateSecretKey(B);
Console.WriteLine($"APP computed key: {keyA}");
BigInteger keyB = espDH.GenerateSecretKey(A);
Console.WriteLine($"ESP computed key: {keyB}");
if (keyA == keyB)
{
Console.WriteLine("Key exchange successful! Both parties have the same shared key.");
}
else
{
Console.WriteLine("Key exchange failed! The keys do not match.");
}
DH Negotiate Security
@startuml DH Negotiate Security
participant APP as a
participant ESP as b
activate a
a -[#Green]> a: Generate g, p
a -[#Green]> a: Private key: a
a -[#Green]> a: Public key: A = g^a mod p
a -[#Blue]> b: Send: A, g, p
activate b
b -[#Green]> b: Private key: b
b -[#Green]> b: Public key: B = g^b mod p
b -[#Blue]> a: Send: B
b -[#DarkRed]> b: Shared key: K = A^b mod p
activate a
a -[#DarkRed]> a: Shared key: K = B^a mod p
@enduml
