workaround for supporting dart html/web.

.idea/dictionaries/herbert.xml

@@ -7,6 +7,7 @@
       <w>hmac</w>
       <w>kdbx</w>
       <w>keepass</w>
+      <w>uint</w>
     </words>
   </dictionary>
 </component>

bin/kdbx.dart

@@ -94,7 +94,7 @@ abstract class KdbxFileCommand extends Command<void> {
     final keyFileData =
         keyFile == null ? null : await File(keyFile).readAsBytes();
 
-    Argon2FfiFlutter.resolveLibraryForceDynamic = true;
+    Argon2.resolveLibraryForceDynamic = true;
     final file = await KdbxFormat(Argon2FfiFlutter()).read(
       bytes,
       Credentials.composite(ProtectedValue.fromString(password), keyFileData),

lib/src/internal/byte_utils.dart

@@ -3,6 +3,14 @@ import 'dart:io';
 import 'dart:math';
 import 'dart:typed_data';
 
+import 'package:kdbx/kdbx.dart';
+
+/// A bitmask that limits an integer to 32 bits.
+const mask32 = 0xFFFFFFFF;
+
+/// The number of bytes in a 32-bit word.
+const bytesPerWord = 4;
+
 class ByteUtils {
   static final _random = Random.secure();
 
@@ -27,8 +35,13 @@ class ByteUtils {
       list?.map((val) => toHex(val))?.join(' ') ?? '(null)';
 }
 
+const dartWebWorkaround = true;
+
 class ReaderHelper {
-  ReaderHelper(this.byteData) : lengthInBytes = byteData.lengthInBytes;
+  factory ReaderHelper(Uint8List byteData) => KdbxFormat.dartWebWorkaround
+      ? ReaderHelper(byteData)
+      : ReaderHelper._(byteData);
+  ReaderHelper._(this.byteData) : lengthInBytes = byteData.lengthInBytes;
 
   final Uint8List byteData;
   int pos = 0;
@@ -72,10 +85,24 @@ class ReaderHelper {
   int readUint8() => _nextByteBuffer(1).getUint8(0);
   int readUint16() => _nextByteBuffer(2).getUint16(0, Endian.little);
   int readUint32() => _nextByteBuffer(4).getUint32(0, Endian.little);
-  int readUint64() => _nextByteBuffer(8).getUint64(0, Endian.little);
+  int readUint64() {
+    if (!dartWebWorkaround) {
+      return _nextByteBuffer(8).getUint64(0, Endian.little);
+    } else {
+      final lo = readUint32();
+      final hi = readUint32();
+      return hi << 32 + lo;
+    }
+  }
 
   int readInt32() => _nextByteBuffer(4).getInt32(0, Endian.little);
-  int readInt64() => _nextByteBuffer(8).getInt64(0, Endian.little);
+  int readInt64() {
+    if (!dartWebWorkaround) {
+      return _nextByteBuffer(8).getInt64(0, Endian.little);
+    } else {
+      return readUint64();
+    }
+  }
 
   Uint8List readBytes(int size) => _nextBytes(size);
 
@@ -90,10 +117,17 @@ class ReaderHelper {
   static int singleUint64(Uint8List bytes) => ReaderHelper(bytes).readUint64();
 }
 
+class ReaderHelperDartWeb extends ReaderHelper {
+  ReaderHelperDartWeb(Uint8List byteData) : super._(byteData);
+}
+
 typedef LengthWriter = void Function(int length);
 
 class WriterHelper {
-  WriterHelper([BytesBuilder output]) : output = output ?? BytesBuilder();
+  factory WriterHelper([BytesBuilder output]) => KdbxFormat.dartWebWorkaround
+      ? WriterHelperDartWeb(output)
+      : WriterHelper._(output);
+  WriterHelper._([BytesBuilder output]) : output = output ?? BytesBuilder();
 
   final BytesBuilder output;
 
@@ -148,3 +182,30 @@ class WriterHelper {
     return bytes.length;
   }
 }
+
+class WriterHelperDartWeb extends WriterHelper {
+  WriterHelperDartWeb([BytesBuilder output]) : super._(output);
+
+  @override
+  void writeUint64(int value, [LengthWriter lengthWriter]) {
+    lengthWriter?.call(8);
+
+    final _endian = Endian.little;
+    final highBits = value >> 32;
+    final lowBits = value & mask32;
+    final byteData = ByteData(8);
+    if (_endian == Endian.big) {
+      byteData.setUint32(0, highBits, _endian);
+      byteData.setUint32(0 + bytesPerWord, lowBits, _endian);
+    } else {
+      byteData.setUint32(0, lowBits, _endian);
+      byteData.setUint32(0 + bytesPerWord, highBits, _endian);
+    }
+    _write(byteData);
+  }
+
+  @override
+  void writeInt64(int value, [LengthWriter lengthWriter]) {
+    writeUint64(value, lengthWriter);
+  }
+}

lib/src/kdbx_format.dart

@@ -324,6 +324,7 @@ class KdbxFormat {
   KdbxFormat([this.argon2]);
 
   final Argon2 argon2;
+  static bool dartWebWorkaround = false;
 
   KdbxFile create(
     Credentials credentials,

pubspec.yaml

@@ -29,7 +29,7 @@ dependencies:
   args: '>1.5.0 <2.0.0'
   prompts: '>=1.3.0 <2.0.0'
   logging_appenders: '>=0.1.0 <1.0.0'
-  argon2_ffi_base: '>=0.1.0 <1.0.0'
+  argon2_ffi_base: '>=0.1.4+2 <1.0.0'
 
 dev_dependencies:
   pedantic: '>=1.7.0 <2.0.0'

test/internal/test_utils.dart

@@ -13,7 +13,7 @@ final _logger = Logger('test_utils');
 
 class TestUtil {
   static KdbxFormat kdbxFormat() {
-    Argon2FfiFlutter.resolveLibraryForceDynamic = true;
+    Argon2.resolveLibraryForceDynamic = true;
     return KdbxFormat(Argon2FfiFlutter(resolveLibrary: (path) {
       final cwd = Directory('.').absolute.uri;
       final p = cwd.resolve(path);