zig: x25519 handshake

main.zig

const std = @import("std");

pub fn main() !void {
    const server_keys = try std.crypto.sign.Ed25519.KeyPair.create(null);
    const client_keys = try std.crypto.sign.Ed25519.KeyPair.create(null);

    std.log.info("server secret key: {s}", .{std.fmt.fmtSliceHexLower(&server_keys.secret_key)});
    std.log.info("server public key: {s}", .{std.fmt.fmtSliceHexLower(&server_keys.public_key)});

    std.log.info("client secret key: {s}", .{std.fmt.fmtSliceHexLower(&client_keys.secret_key)});
    std.log.info("client public key: {s}", .{std.fmt.fmtSliceHexLower(&client_keys.public_key)});

    const server_x25519_keys = try std.crypto.dh.X25519.KeyPair.fromEd25519(server_keys);
    const client_x25519_keys = try std.crypto.dh.X25519.KeyPair.fromEd25519(client_keys);

    const server_recovered_shared_secret = try std.crypto.dh.X25519.scalarmult(server_x25519_keys.secret_key, try std.crypto.dh.X25519.publicKeyFromEd25519(client_keys.public_key));
    const client_recovered_shared_secret = try std.crypto.dh.X25519.scalarmult(client_x25519_keys.secret_key, try std.crypto.dh.X25519.publicKeyFromEd25519(server_keys.public_key));

    std.log.info("server recovered shared secret: {s}", .{std.fmt.fmtSliceHexLower(&server_recovered_shared_secret)});
    std.log.info("client recovered shared secret: {s}", .{std.fmt.fmtSliceHexLower(&client_recovered_shared_secret)});

    // info: server secret key: 7931ed55efd0708b44835cf0d86d775e4b4506bba526f1c5facabe66e285bb41888b9325b34eb41c832f025363e1b318604c75348332fae22a60d9f34313bd87
    // info: server public key: 888b9325b34eb41c832f025363e1b318604c75348332fae22a60d9f34313bd87
    // info: client secret key: 9df89363f95de2fa74081114f16783373515239a2604bab2c0e562db4c97096be307934bf5cdb4b70dab03b89201b33e2808a28e2a4db55318aae19ec0b4e1e5
    // info: client public key: e307934bf5cdb4b70dab03b89201b33e2808a28e2a4db55318aae19ec0b4e1e5
    // info: server recovered shared secret: 42a1c418fcfd32080df8a67aaf12a3a6ac29845189937d68790751c47f0f0f5d
    // info: client recovered shared secret: 42a1c418fcfd32080df8a67aaf12a3a6ac29845189937d68790751c47f0f0f5d
}