---
title: "How NuFilebox Reverse strengthens file security at Nubank"
url: https://daily.dev/posts/how-nufilebox-reverse-strengthens-file-security-at-nubank-9ib7ayncu
source_url: https://building.nubank.com/nufilebox-reverse/
type: article
source: "Nubank"
published: 2025-12-19T13:11:00.654Z
updated: 2025-12-19T13:11:24.816Z
tags: ["cyber", "aws", "encryption", "clojure"]
reading_time: 1
upvotes: 0
comments: 0
language: en
---

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# How NuFilebox Reverse strengthens file security at Nubank

**[Nubank](https://daily.dev/sources/nubank)** · 1 min read · 0 upvotes · 0 comments

## Summary

NuFilebox Reverse is a zero-knowledge file upload system developed through a research partnership between Nubank and Brazilian universities. The system uses Clojure as its core, implementing client-side encryption before files leave the user's machine, splitting large files into encrypted chunks uploaded directly to S3, and performing malware detection using YARA rules after server-side decryption and reassembly. The architecture ensures the server never accesses unencrypted content, handling files up to 30GB with performance superior to commercial alternatives while maintaining strict security through immutability and functional programming principles.

## Full article

daily.dev links to this article rather than hosting it. Read it at the original source: <https://building.nubank.com/nufilebox-reverse/>

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---

Tags: [#cyber](https://daily.dev/tags/cyber), [#aws](https://daily.dev/tags/aws), [#encryption](https://daily.dev/tags/encryption), [#clojure](https://daily.dev/tags/clojure)

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