Refactored the missing X25519 functions to use keypairs, consume seed buffers once they have been used (fill with zeroes), fixed the remaining compilation issues with identity.zig

src/crypto.zig

@@ -1,14 +1,14 @@
 ///////////////// Imports
 //
 
-const AES = @import("crypto/aes.zig");
-const ED25519 = @import("crypto/ed25519.zig");
-const HKDF = @import("crypto/hkdf.zig");
-const HMAC = @import("crypto/hmac.zig");
-const SHA256 = @import("crypto/sha256.zig");
-const SHA512 = @import("crypto/sha512.zig");
-const X25519= @import("crypto/x25519.zig");
-const RANDOM = @import("crypto/random.zig");
+pub const Aes = @import("crypto/aes.zig");
+pub const Ed25519 = @import("crypto/ed25519.zig");
+pub const Hkdf = @import("crypto/hkdf.zig");
+pub const Hmac = @import("crypto/hmac.zig");
+pub const Sha256 = @import("crypto/sha256.zig");
+pub const Sha512 = @import("crypto/sha512.zig");
+pub const X25519= @import("crypto/x25519.zig");
+pub const Random = @import("crypto/random.zig");
 
 
 ///////////////// Errors
@@ -25,25 +25,25 @@ pub const CryptoError = error {
 //
 
 pub const PartialEngine = struct {
-    aes_cbc256: ? AES.CBC256.Implementation = null,
-    ed25519:    ? ED25519.Implementation    = null,
-    hkdf:       ? HKDF.Implementation       = null,
-    hmac:       ? HMAC.Implementation       = null,
-    sha256:     ? SHA256.Implementation     = null,
-    sha512:     ? SHA512.Implementation     = null,
+    aes_cbc256: ? Aes.CBC256.Implementation = null,
+    ed25519:    ? Ed25519.Implementation    = null,
+    hkdf:       ? Hkdf.Implementation       = null,
+    hmac:       ? Hmac.Implementation       = null,
+    sha256:     ? Sha256.Implementation     = null,
+    sha512:     ? Sha512.Implementation     = null,
     x25519:     ? X25519.Implementation     = null,
-    random:     ? RANDOM.Implementation     = null,
+    random:     ? Random.Implementation     = null,
 };
 
 pub const Engine = struct {
-    aes_cbc256: AES.CBC256.Implementation,
-    ed25519:    ED25519.Implementation,
-    hkdf:       HKDF.Implementation,
-    hmac:       HMAC.Implementation,
-    sha256:     SHA256.Implementation,
-    sha512:     SHA512.Implementation,
+    aes_cbc256: Aes.CBC256.Implementation,
+    ed25519:    Ed25519.Implementation,
+    hkdf:       Hkdf.Implementation,
+    hmac:       Hmac.Implementation,
+    sha256:     Sha256.Implementation,
+    sha512:     Sha512.Implementation,
     x25519:     X25519.Implementation,
-    random:     RANDOM.Implementation,
+    random:     Random.Implementation,
 };
 
 
@@ -56,14 +56,14 @@ pub const Engine = struct {
 pub fn resolveEngine(comptime provider: PartialEngine) Engine {
 
     return .{
-        .aes_cbc256 = provider.aes_cbc256 orelse AES.CBC256.defaultImplementation,
-        .ed25519    = provider.ed25519    orelse ED25519.defaultImplementation,
-        .hkdf       = provider.hkdf       orelse HKDF.defaultImplementation,
-        .hmac       = provider.hmac       orelse HMAC.defaultImplementation,
-        .sha256     = provider.sha256     orelse SHA256.defaultImplementation,
-        .sha512     = provider.sha512     orelse SHA512.defaultImplementation,
+        .aes_cbc256 = provider.aes_cbc256 orelse Aes.CBC256.defaultImplementation,
+        .ed25519    = provider.ed25519    orelse Ed25519.defaultImplementation,
+        .hkdf       = provider.hkdf       orelse Hkdf.defaultImplementation,
+        .hmac       = provider.hmac       orelse Hmac.defaultImplementation,
+        .sha256     = provider.sha256     orelse Sha256.defaultImplementation,
+        .sha512     = provider.sha512     orelse Sha512.defaultImplementation,
         .x25519     = provider.x25519     orelse X25519.defaultImplementation,
-        .random     = provider.random     orelse RANDOM.defaultImplementation,
+        .random     = provider.random     orelse Random.defaultImplementation,
     };
 }
 

src/crypto/ed25519.zig

@@ -2,40 +2,42 @@
 const CryptoError = @import("../crypto.zig").CryptoError;
 // Constants and default implementation
 const Ed25519 = @import("std").crypto.sign.Ed25519;
+const secureZero = @import("std").crypto.secureZero;
 // Random number generation
 const rngProvider = @import("random.zig").Implementation;
 
-pub const secret_key_size: comptime_int = Ed25519.SecretKey.encoded_length;
-pub const public_key_size: comptime_int = Ed25519.PublicKey.encoded_length;
-pub const signature_size : comptime_int = Ed25519.Signature.encoded_length;
+// Keypair type
+pub const KeyPair = Ed25519.KeyPair;
+
+pub const secret_key_length: comptime_int = Ed25519.SecretKey.encoded_length;
+pub const public_key_length: comptime_int = Ed25519.PublicKey.encoded_length;
+pub const signature_length : comptime_int = Ed25519.Signature.encoded_length;
+pub const seed_length : comptime_int = Ed25519.Signature.encoded_length;
 
 pub const Implementation = struct {
 
-    generateKeys: *const fn (pubkey_buffer: *[public_key_size]u8, privkey_buffer: *[secret_key_size]u8, rng: rngProvider) CryptoError!void,
-    sign: *const fn (key: *const [secret_key_size]u8, data: []const u8, signature_out: *const [signature_size]u8) CryptoError!void,
-    verify: *const fn (key: *const [public_key_size]u8, signature: *const [signature_size]u8, data: []const u8) CryptoError!void,
+    generateKeys: *const fn (destination: *KeyPair, rng: rngProvider) CryptoError!void,
+    sign: *const fn (key: *const [secret_key_length]u8, data: []const u8, signature_out: *const [signature_length]u8) CryptoError!void,
+    verify: *const fn (key: *const [public_key_length]u8, signature: *const [signature_length]u8, data: []const u8) CryptoError!void,
 };
 
 
-pub fn generateKeys(pubkey_buffer: *[public_key_size]u8, privkey_buffer: *[secret_key_size]u8, rng: rngProvider) !void {
+pub fn generateKeys (destination: *KeyPair, rng: rngProvider) !void {
     
-    var seed_buffer: [Ed25519.KeyPair.seed_length]u8 = undefined;
+    var seed_buffer: [KeyPair.seed_length]u8 = undefined;
+    defer secureZero(u8, &seed_buffer);
     rng.generate(&seed_buffer);
-    const keypair: Ed25519.KeyPair = Ed25519.KeyPair.generateDeterministic(seed_buffer) catch return CryptoError.FailedKeyGeneration;
-    
-    
-    @memcpy(pubkey_buffer[0..public_key_size], &keypair.public_key.bytes);
-    @memcpy(privkey_buffer[0..secret_key_size], &keypair.secret_key.bytes);
+    destination.* = KeyPair.generateDeterministic(seed_buffer) catch return CryptoError.FailedKeyGeneration;
 }
 
-pub fn sign(key: *const [secret_key_size]u8, data: []const u8, signature_out: *const [signature_size]u8) !void {
+pub fn sign (key: *const [secret_key_length]u8, data: []const u8, signature_out: *const [signature_length]u8) !void {
     _ = key;
     _ = data;
     _ = signature_out;
     return CryptoError.NotImplemented;
 }
 
-pub fn verify(key: *const [public_key_size]u8, signature: *const [signature_size]u8, data: []const u8) !void {
+pub fn verify (key: *const [public_key_length]u8, signature: *const [signature_length]u8, data: []const u8) !void {
     // TODO maybe find a more efficient way to do that (excessive copies)
     const sig = Ed25519.Signature.fromBytes(signature.*);
     const pubkey = Ed25519.PublicKey.fromBytes(key.*) catch return CryptoError.InvalidKey;

src/crypto/x25519.zig

@@ -1,13 +1,38 @@
-//TODO
+// Errors
+const CryptoError = @import("../crypto.zig").CryptoError;
+// Constants and default implementation
+const X25519 = @import("std").crypto.dh.X25519;
+const Ed25519 = @import("std").crypto.sign.Ed25519;
+const secureZero = @import("std").crypto.secureZero;
+// Random number generation
+const rngProvider = @import("random.zig").Implementation;
 
-const X25519 = @import("std").std.crypto.dh.X25519;
+// Keypair type
+pub const KeyPair = X25519.KeyPair;
+
+pub const secret_key_length: comptime_int = X25519.secret_length;
+pub const public_key_length: comptime_int = X25519.public_length;
+pub const seed_length: comptime_int = X25519.seed_length;
 
 pub const Implementation = struct {
     
+    generateKeys: *const fn (destination: *KeyPair, rng: rngProvider) CryptoError!void,
+    fromEd25519: *const fn (ed25519_keypair: *Ed25519.KeyPair, x25519_keypair: *KeyPair) CryptoError!void,
 };
 
+fn generateKeys (destination: *KeyPair, rng: rngProvider) !void {
+    
+    var seed_buffer: [seed_length]u8 = undefined;
+    defer secureZero(u8, &seed_buffer);
+    rng.generate(&seed_buffer);
+    destination.* = X25519.KeyPair.generateDeterministic(seed_buffer) catch return CryptoError.FailedKeyGeneration;
+}
+
+fn fromEd25519 (ed25519_keypair: *Ed25519.KeyPair, x25519_keypair: *KeyPair) CryptoError!void {
+    x25519_keypair.* = X25519.KeyPair.fromEd25519(ed25519_keypair.*) catch return CryptoError.InvalidKey;
+}
+
 pub const defaultImplementation: Implementation = .{
-
-    // One problem, it uses the zig's io module, which is not supported yet as it depends on the target OS
-    // It may need a custom implementation or some other library
+    .generateKeys = generateKeys,
+    .fromEd25519 = fromEd25519,
 };

src/identity.zig

@@ -1,7 +1,7 @@
 ///////////////// Imports
 //
 
-const CryptoEngine = @import("crypto.zig").Engine;
+const Crypto = @import("crypto.zig");
 
 ///////////////// Constants
 //
@@ -13,25 +13,38 @@ const CryptoEngine = @import("crypto.zig").Engine;
 //
 
 // TODO
-pub fn Identity(comptime crypto_engine: CryptoEngine) type {
-    _ = crypto_engine;
+pub fn resolveIdentity(comptime crypto_engine: Crypto.Engine) type {
 
     return struct {
 
+        const Self = @This();
+
         //////// Fields
         //
-        publicKey: []const u8,
-        privateKey: []const u8,
-        signature: []const u8,
-        hash: []const u8,
+        keys: Crypto.Ed25519.KeyPair,
+        signatureKeys: Crypto.X25519.KeyPair,
+        hash: [Crypto.Sha256.hash_len]u8,
 
         //////// Functions
         //
-        pub fn generate() !Identity {
-            return .{
-                // .privateKey = crypto_engine.ed25519.generateKey(...),
-                // .signature = crypto_engine.x25519.
-            };
+        pub fn new() !Self {
+            const result: Self = undefined;
+            crypto_engine.ed25519.generateKeys(result.keys, crypto_engine.random);
+            crypto_engine.x25519.fromEd25519(result.keys, result.signatureKeys, crypto_engine.random);
+            result.update_hash();
+            return result;
+        }
+
+        pub fn generate(self: *Self) !void {
+            try crypto_engine.ed25519.generateKeys(&self.keys, crypto_engine.random);
+            try crypto_engine.x25519.fromEd25519(&self.keys, &self.signatureKeys);
+            self.update_hash();
+        }
+
+        pub fn update_hash(self: *Self) void {
+            //WARNING PUBLIC KEY SHOULD BE TRUNCATED
+            // We should define the truncated hash length somewhere
+            crypto_engine.sha256.hash(&self.keys.public_key.bytes, &self.hash);
         }
     };
 }
@@ -46,3 +59,49 @@ pub fn Identity(comptime crypto_engine: CryptoEngine) type {
 const std = @import("std");
 
 const expect = std.testing.expect;
+const memeql = std.mem.eql;
+
+const testPattern: u8 = 0b10101010;
+const pubkey_size = Crypto.Ed25519.public_key_length;
+const privkey_size = Crypto.Ed25519.secret_key_length;
+
+// Fills out with alternating 0s and 1s
+fn fillPattern(out: []u8) void {
+    for(out) |*byte| {
+        byte.* = testPattern;
+    }
+}
+
+pub fn generateFakeKeys(destination: *Crypto.Ed25519.KeyPair, rng: Crypto.Random.Implementation) Crypto.CryptoError!void {
+    _ = rng;
+    fillPattern(&destination.public_key.bytes);
+    fillPattern(&destination.secret_key.bytes);
+}
+
+test "Basic identity generation" {
+
+    const fake_rng: Crypto.Random.Implementation = .{
+        .generate = fillPattern,
+    };
+    const fake_ed25519: Crypto.Ed25519.Implementation = .{
+        .generateKeys = generateFakeKeys,
+        .sign = undefined,
+        .verify = undefined,
+    };
+    const crypto_engine = comptime Crypto.resolveEngine(.{
+        .random = fake_rng,
+        .ed25519 = fake_ed25519,
+    });
+
+    const Identity = resolveIdentity(crypto_engine);
+    var new_id: Identity = undefined;
+    try new_id.generate();
+
+    const expected_secret_key = [_]u8{testPattern} ** new_id.keys.secret_key.bytes.len;
+    // const expected_signature_key = [_]u8{testPattern} ** new_id.signatureKeys.secret_key.len;
+    try expect(memeql(u8, &new_id.keys.secret_key.bytes, &expected_secret_key));
+    // try expect(memeql(u8, &new_id.signatureKeys.secret_key, &expected_signature_key));
+    
+    // try expect(memeql(u8, new_id.hash, testPattern));
+    
+}