diff --git a/crypto-test/.gitignore b/crypto-test/.gitignore
new file mode 100644
index 0000000..7c1baea
--- /dev/null
+++ b/crypto-test/.gitignore
@@ -0,0 +1,5 @@
+.idea/
+zig-out/
+zig-cache/
+
+/src/vk.zig
diff --git a/crypto-test/build.zig b/crypto-test/build.zig
new file mode 100644
index 0000000..3141ec0
--- /dev/null
+++ b/crypto-test/build.zig
@@ -0,0 +1,83 @@
+const std = @import("std");
+
+pub fn build(b: *std.Build) void {
+    const target = b.standardTargetOptions(.{});
+    const optimize = b.standardOptimizeOption(.{});
+
+    const enet_real = b.dependency("enet_real", .{});
+    const enet = b.createModule(.{
+        .root_source_file = .{ .path = "src/enet.zig" },
+        .target = target,
+        .optimize = optimize,
+        .link_libc = true,
+        .sanitize_c = false,
+    });
+    enet.addCSourceFiles(.{
+        .root = enet_real.path(""),
+        .files = &.{
+            "callbacks.c",
+            "compress.c",
+            "host.c",
+            "list.c",
+            "packet.c",
+            "peer.c",
+            "protocol.c",
+            "unix.c",
+            "win32.c",
+        },
+    });
+    enet.addIncludePath(enet_real.path("include"));
+
+    const client = b.addExecutable(.{
+        .name = "client",
+        .root_source_file = .{ .path = "src/client.zig" },
+        .target = target,
+        .optimize = optimize,
+    });
+    client.root_module.addImport("enet", enet);
+    b.installArtifact(client);
+
+    const server = b.addExecutable(.{
+        .name = "server",
+        .root_source_file = .{ .path = "src/server.zig" },
+        .target = target,
+        .optimize = optimize,
+    });
+    server.root_module.addImport("enet", enet);
+    b.installArtifact(server);
+
+    const client_cmd = b.addRunArtifact(client);
+    client_cmd.step.dependOn(b.getInstallStep());
+    const server_cmd = b.addRunArtifact(server);
+    server_cmd.step.dependOn(b.getInstallStep());
+
+    if (b.args) |args| {
+        client_cmd.addArgs(args);
+        server_cmd.addArgs(args);
+    }
+
+    const client_step = b.step("client", "Run the client");
+    client_step.dependOn(&client_cmd.step);
+    const server_step = b.step("server", "Run the server");
+    server_step.dependOn(&server_cmd.step);
+
+    const client_tests = b.addTest(.{
+        .root_source_file = .{ .path = "src/client.zig" },
+        .target = target,
+        .optimize = optimize,
+    });
+    client_tests.root_module.addImport("enet", enet);
+    const server_tests = b.addTest(.{
+        .root_source_file = .{ .path = "src/server.zig" },
+        .target = target,
+        .optimize = optimize,
+    });
+    server_tests.root_module.addImport("enet", enet);
+
+    const run_client_tests = b.addRunArtifact(client_tests);
+    const run_server_tests = b.addRunArtifact(server_tests);
+
+    const test_step = b.step("test", "Run tests");
+    test_step.dependOn(&run_client_tests.step);
+    test_step.dependOn(&run_server_tests.step);
+}
diff --git a/crypto-test/build.zig.zon b/crypto-test/build.zig.zon
new file mode 100644
index 0000000..6a4662f
--- /dev/null
+++ b/crypto-test/build.zig.zon
@@ -0,0 +1,15 @@
+.{
+    .name = "learnzig",
+    .version = "0.0.0",
+
+    .dependencies = .{
+        .enet_real = .{
+            .url = "https://github.com/lsalzman/enet/archive/c44b7d0f7ff21edb702745e4c019d0537928c373.tar.gz",
+            .hash = "1220b65591d2f97033626dfff25a37926b250c7892e812397668769f84ef408cd02e",
+        },
+    },
+
+    .paths = .{
+        "",
+    },
+}
diff --git a/crypto-test/src/client.zig b/crypto-test/src/client.zig
new file mode 100644
index 0000000..33a457b
--- /dev/null
+++ b/crypto-test/src/client.zig
@@ -0,0 +1,69 @@
+const std = @import("std");
+const enet = @import("enet");
+
+const DH = std.crypto.dh.X25519;
+const AES = std.crypto.aead.aes_gcm.Aes256Gcm;
+const SHA = std.crypto.hash.sha2.Sha256;
+
+pub fn main() !void {
+    if (enet.enet_initialize() != 0) return error.ENetInitFailed;
+    defer enet.enet_deinitialize();
+
+    const addr = enet.ENetAddress{
+        .host = enet.ENET_HOST_ANY,
+        .port = enet.ENET_PORT_ANY,
+    };
+    const host = enet.enet_host_create(&addr, 32, 1, 0, 0) orelse return error.ENetHostCreateFailed;
+    defer enet.enet_host_destroy(host);
+
+    var server_addr = enet.ENetAddress{
+        .host = enet.ENET_HOST_ANY,
+        .port = 9405,
+    };
+    _ = enet.enet_address_set_host(&server_addr, "localhost");
+    const peer = enet.enet_host_connect(host, &server_addr, 1, 0);
+    _ = peer;
+
+    var event: enet.ENetEvent = undefined;
+
+    while (true) {
+        while (enet.enet_host_service(host, &event, 100) > 0) {
+            switch (event.type) {
+                enet.ENET_EVENT_TYPE_CONNECT => {
+                    std.debug.print("client: connected to peer {any}\n", .{event.peer.*.address});
+                },
+                else => {
+                    std.debug.print("client: other event...\n", .{});
+                },
+            }
+        }
+    }
+}
+
+// it even works in ReleaseFast so I think it's ok.
+test "in-place-encrypt" {
+    const al = std.testing.allocator;
+
+    var key: [AES.key_length]u8 = undefined;
+    std.crypto.random.bytes(&key);
+    const iv: [AES.nonce_length]u8 = undefined;
+    std.crypto.random.bytes(&key);
+
+    var tag: [AES.tag_length]u8 = undefined;
+
+    // 1mb message. very big. should find an error if one exists.
+    const original_message: []u8 = try al.alloc(u8, 1 << 20);
+    defer al.free(original_message);
+    std.crypto.random.bytes(original_message);
+
+    const message = try al.dupe(u8, original_message);
+    defer al.free(message);
+
+    const ad: []u8 = try al.dupe(u8, "u");
+    defer al.free(ad);
+
+    AES.encrypt(message, &tag, message, ad, iv, key);
+    try std.testing.expect(!std.mem.eql(u8, message, original_message));
+    try AES.decrypt(message, message, tag, ad, iv, key);
+    try std.testing.expect(std.mem.eql(u8, message, original_message));
+}
diff --git a/crypto-test/src/enet.zig b/crypto-test/src/enet.zig
new file mode 100644
index 0000000..1aa9def
--- /dev/null
+++ b/crypto-test/src/enet.zig
@@ -0,0 +1,7 @@
+const c = @This();
+
+pub usingnamespace @cImport({
+    @cInclude("enet/enet.h");
+});
+
+// todo add "serve" here that invokes some callback with events.
diff --git a/crypto-test/src/server.zig b/crypto-test/src/server.zig
new file mode 100644
index 0000000..4ed311e
--- /dev/null
+++ b/crypto-test/src/server.zig
@@ -0,0 +1,61 @@
+const std = @import("std");
+const enet = @import("enet");
+
+const DH = std.crypto.dh.X25519;
+const AES = std.crypto.aead.aes_gcm.Aes256Gcm;
+const SHA = std.crypto.hash.sha2.Sha256;
+
+pub fn main() !void {
+    if (enet.enet_initialize() != 0) return error.ENetInitFailed;
+    defer enet.enet_deinitialize();
+
+    const addr = enet.ENetAddress{
+        .host = enet.ENET_HOST_ANY,
+        .port = 9405,
+    };
+    const host = enet.enet_host_create(&addr, 32, 1, 0, 0) orelse return error.ENetHostCreateFailed;
+    defer enet.enet_host_destroy(host);
+
+    var event: enet.ENetEvent = undefined;
+
+    while (true) {
+        while (enet.enet_host_service(host, &event, 100) > 0) {
+            switch (event.type) {
+                enet.ENET_EVENT_TYPE_CONNECT => {
+                    std.debug.print("server: connected to peer {any}\n", .{event.peer.*.address});
+                },
+                else => {
+                    std.debug.print("server: other event...\n", .{});
+                },
+            }
+        }
+    }
+}
+
+// it even works in ReleaseFast so I think it's ok.
+test "in-place-encrypt" {
+    const al = std.testing.allocator;
+
+    var key: [AES.key_length]u8 = undefined;
+    std.crypto.random.bytes(&key);
+    const iv: [AES.nonce_length]u8 = undefined;
+    std.crypto.random.bytes(&key);
+
+    var tag: [AES.tag_length]u8 = undefined;
+
+    // 1mb message. very big. should find an error if one exists.
+    const original_message: []u8 = try al.alloc(u8, 1 << 20);
+    defer al.free(original_message);
+    std.crypto.random.bytes(original_message);
+
+    const message = try al.dupe(u8, original_message);
+    defer al.free(message);
+
+    const ad: []u8 = try al.dupe(u8, "u");
+    defer al.free(ad);
+
+    AES.encrypt(message, &tag, message, ad, iv, key);
+    try std.testing.expect(!std.mem.eql(u8, message, original_message));
+    try AES.decrypt(message, message, tag, ad, iv, key);
+    try std.testing.expect(std.mem.eql(u8, message, original_message));
+}