The `encryptFile` and `decryptFile` methods do not support streaming and will cause an OutOfMemoryError (OOM) when encrypting or decrypting large files.

[amd110]

Preflight Checklist

• I could not find a solution in the existing issues, docs, nor discussions

Describe your problem

Future encryptFile(Uint8List input) async {
final key = secureRandomBytes(32);
final iv = secureRandomBytes(16);
final data = CryptoUtils.aesCtr(input: input, key: key, iv: iv);
final hash = CryptoUtils.sha256(input: data);
return EncryptedFile(
data: data,
k: base64Url.encode(key).replaceAll('=', ''),
iv: base64.encode(iv).replaceAll('=', ''),
sha256: base64.encode(hash).replaceAll('=', ''),
);
}
Future<Uint8List?> decryptFile(EncryptedFile input) async {
if (base64.encode(await sha256(input.data)) !=
base64.normalize(input.sha256)) {
return null;
}

final key = base64decodeUnpadded(base64.normalize(input.k));
final iv = base64decodeUnpadded(base64.normalize(input.iv));
return await aesCtr.encrypt(input.data, key, iv);
}
File streams are not supported, and an OutOfMemoryError (OOM) will occur when encrypting or decrypting large files.

Describe your ideal solution

none

Version

No response

Security requirements

No response

Additional Context

No response

[amd110]

Critical Memory Bottleneck: Out-of-Memory (OOM) Risk for Large Files

• Problem: MatrixFile's core data storage uses a final Uint8List bytes. This means that whether it's a 1MB image or a 1GB video, its complete binary data will be loaded entirely into memory.

• Analysis: For mobile apps (like Flutter), if a user chooses to send a 500MB video file, allocating a 500MB Uint8List when building MatrixVideoFile can easily trigger an OOM crash on the device. Furthermore, encrypting also encrypts the byte array in memory.

• Improvement Recommendation: For future support of truly large files, MatrixFile's design should abstract to support streams (Stream<List>) or local file paths (File), instead of forcing the entire file to be loaded as a Uint8List.

[amd110]

• Image Decoding Memory Pressure

• Problem: The decodeImage(bytes) method is used in calcMetadataImplementation and resizeImplementation.

• Analysis: When performing decodeImage, the package:image library completely decompresses the image into a raw bitmap array. A standard 4K resolution (3840×2160) JPG image, when decompressed into memory, can instantly occupy approximately 3840 * 2160 * 4 = 33MB of memory. If a user selects 10 more high-resolution original images from their album to send, the backlog in the Isolate queue will still cause a significant memory spike.