WIP: dh / aes testing

src/main.zig

@@ -1,19 +1,119 @@
 const std = @import("std");
 
+const DH = std.crypto.dh.X25519;
+const AES = std.crypto.aead.aes_gcm.Aes256Gcm;
+const SHA = std.crypto.hash.sha2.Sha256;
+
+const Encryptor = struct {
+    const Self = @This();
+
+    kp: DH.KeyPair,
+
+    pub fn init() !Self {
+        const self = Self{};
+
+        var seed: [DH.seed_length]u8 = undefined;
+        std.crypto.random.bytes(&seed);
+        self.kp = try DH.KeyPair.create(seed);
+        @memset(seed, 0);
+
+        return self;
+    }
+};
+
+const Peer = struct {
+    const Self = @This();
+
+    public_key: [DH.public_length]u8,
+    shared_key: [AES.key_length]u8,
+
+    pub fn init(me: DH.KeyPair, peer_key: [DH.public_length]u8) Self {
+        const self = Self{ .public_key = peer_key };
+
+        const secret = try DH.scalarmult(me.secret_key, peer_key);
+        SHA.hash(&secret, self.shared_key, .{});
+
+        return self;
+    }
+
+    pub fn encrypt(ally: std.mem.Allocator, msg: []const u8) !Packet {
+        var pkt: Packet = undefined;
+        std.crypto.random.bytes(&pkt.nonce);
+    }
+};
+
+const Packet = struct {
+    ally: std.mem.Allocator,
+    nonce: [AES.tag_length]u8,
+
+    cipher_text: []u8,
+};
+
 pub fn main() !void {
-    // Prints to stderr (it's a shortcut based on `std.io.getStdErr()`)
-    std.debug.print("All your {s} are belong to us.\n", .{"codebase"});
+    const me = try Encryptor.init();
+    const him = try Encryptor.init();
 
-    // stdout is for the actual output of your application, for example if you
-    // are implementing gzip, then only the compressed bytes should be sent to
-    // stdout, not any debugging messages.
-    const stdout_file = std.io.getStdOut().writer();
-    var bw = std.io.bufferedWriter(stdout_file);
-    const stdout = bw.writer();
+    const my_peer = Peer.init(me, him.kp.public_key);
+    const his_peer = Peer.init(him, me.kp.public_key);
 
-    try stdout.print("Run `zig build test` to run the tests.\n", .{});
+    var seed: [dh.X25519.seed_length]u8 = undefined;
+    std.crypto.random.bytes(&seed);
+    const kp1 = try dh.X25519.KeyPair.create(seed);
+    std.crypto.random.bytes(&seed);
+    const kp2 = try dh.X25519.KeyPair.create(seed);
 
-    try bw.flush(); // don't forget to flush!
+    std.debug.print("{any}\n{any}\n\n", .{ kp1.public_key, kp1.secret_key });
+    std.debug.print("{any}\n{any}\n\n", .{ kp2.public_key, kp2.secret_key });
+
+    const sec_1 = try dh.X25519.scalarmult(kp1.secret_key, kp2.public_key);
+    const sec_2 = try dh.X25519.scalarmult(kp2.secret_key, kp1.public_key);
+
+    var key: [aead.aes_gcm.Aes256Gcm.key_length]u8 = undefined;
+    std.crypto.hash.sha2.Sha256.hash(&sec_1, &key, .{});
+
+    std.debug.print("{any}\n", .{sec_1});
+    std.debug.print("{any}\n", .{sec_2});
+
+    var gpa = std.heap.GeneralPurposeAllocator(.{}){};
+    const ally = gpa.allocator();
+
+    const m: []const u8 = "hello world!";
+    const ad: []const u8 = "foo";
+
+    // see https://crypto.stackexchange.com/a/5818
+    // the nonce does not need to be random, it can be a counter
+    // it can be sent in clear, or each end may deduce it
+    // but it ___MUST___ be unique and unrelated to the key
+    var iv: [aead.aes_gcm.Aes256Gcm.nonce_length]u8 = undefined;
+    std.crypto.random.bytes(&iv);
+
+    const c: []u8 = try ally.alloc(u8, m.len);
+    defer ally.free(c);
+
+    @memset(c, 0);
+    var tag: [aead.aes_gcm.Aes256Gcm.tag_length]u8 = undefined;
+
+    std.debug.print("c: {any}\n", .{c});
+    aead.aes_gcm.Aes256Gcm.encrypt(c, &tag, m, ad, iv, key);
+    std.debug.print("{any} {any} {any}\n", .{ c, tag, iv });
+
+    // aead.aes_gcm.Aes256Gcm.encrypt(c: []u8, tag: *[tag_length]u8, m: []const u8, ad: []const u8, npub: [nonce_length]u8, key: [key_length]u8)
+
+    // var seed_a = [sign.Ed25519.KeyPair.seed_length]u8;
+    // std.crypto.random.bytes(&seed_a);
+    // const pair_a = try sign.Ed25519.KeyPair.create(seed_a);
+    // var pubkey_a = dh.X25519.publicKeyFromEd25519(pair_a.public_key);
+    //
+    // var seed_b = [sign.Ed25519.KeyPair.seed_length]u8;
+    // std.crypto.random.bytes(&seed_b);
+    // const pair_b = try sign.Ed25519.KeyPair.create(seed_b);
+    // var pubkey_b = try dh.X25519.publicKeyFromEd25519(pair_b.public_key);
+
+    // var buf: [64]u8 = undefined;
+    // @memset(&buf, 0);
+    // std.debug.print("{any}\n", .{buf});
+    // std.crypto.random.bytes(&buf);
+    // std.debug.print("{any}\n", .{buf});
 }
 
 test "simple test" {