In This Article
Encrypted file sharing is a method that ensures only authorized users can access specific files. Cloud storage services like Dropbox, Google Drive, and Amazon S3 popularized encrypted file sharing, allowing authorized users to access files from anywhere. Centralized cloud storage providers allow file owners to specify which users or groups can access specific files.
This move revolutionized work teams and directly connected businesses with customers, eliminating the need to send sensitive files via email or make a trip to the office.
Now, a new wave of decentralized file storage protocols offers the convenience of encrypted file sharing services while providing more privacy, better redundancy, and enhanced security for sensitive data. Better yet, decentralized file sharing often provides a more affordable solution. In this guide, we’ll explore storage solutions for encrypted file transfers and file sharing, with a look at blockchain-based solutions as well.
Encrypted File Sharing Explained
Encrypted File Sharing is a secure method of storing files while providing permissioned access to specific files. Many of us use encrypted file-sharing tools daily in our work, such as Google Drive, Box, or Amazon S3. As consumers, we use similar technology, including shared files from realtors, auto dealers, and other vendors and the ability to share our own files using products like OneDrive, Dropbox, or Google Drive.
These services store the file and then allow the file owner to share it, setting permissions for who can view or modify the file.
How Does File Transfer Encryption Work?
Under the hood, cloud storage platforms use a similar approach to ensure secure file sharing. However, the mechanics are abstracted and automated for ease of use. The process involves encrypting the data (making it unreadable) and only allowing authorized users to view the decrypted file.
- Encryption: When a user uploads a file to a cloud storage provider, the file is encrypted to prevent unauthorized access and ensure confidentiality. This process involves using an algorithm to create an alphanumeric representation of the file. A key secures the file, allowing encryption and decryption.
- Secure storage and transmission: Once encrypted, the file is unreadable and ready for secure storage on a cloud server. Even if the file is accessed during transfer, the contents are unreadable.
- Key management: Two primary methods secure the encrypted data: symmetric encryption or asymmetric encryption. Symmetric encryption uses the same key for encryption and decryption. Asymmetric encryption uses a public key to encrypt and a specific private key to decrypt the file.
- Controlled access: File sharers can often set granular permissions, limiting access to a group or role, a specific person, or anyone with the link. Some platforms may also support passwords.
- Decryption: If the recipient is authorized to view the file, they can view the shared file.
Decentralized file storage systems employ a similar approach, although a cryptocurrency wallet controls access rather than a standard username and password login.
Uses of Encrypted File Sharing
File encryption offers several advantages, all of which center on privacy, controlled access, or regulatory compliance. However, encrypted file sharing also introduces more efficiency. Let’s explore some of the leading use cases.
Remote Work Collaboration
Most of us have used encrypted file sharing in a work setting. Whether it’s a shared document from Human Resources, a task list, or a detailed assignment, encryption allows us to share these files, with the owner controlling who can access them or make changes.
Personal Identifiable Information and Financial Data
Files may include financial information or personal identifiable information, such as bank statements, billing information, or identity documents. Encrypted file transfers can help protect this type of data when it needs to be shared.
However, encrypted file sharing doesn’t provide total protection in all situations. The 2023 National Public Data (NPD) breach stemmed from an inadvertent posting of NPD’s administrator credentials. These are the keys we discussed earlier. Ultimately, a database containing 2.9 billion records, including names and Social Security numbers, was made available on the dark web.
Legal Documents and Client Communications
If you’ve purchased a home, rented an apartment, or worked with an attorney in recent years, the attorney or other parties likely used encrypted file sharing. These use cases range from mortgage documents to disclosures, or in another variant, documents that require signatures.
Protected Health Information
Encrypted file sharing can also protect personal health information, whether sharing data or reports with patients or colleagues working in a medical team. A growing industry segment focuses on HIPAA-compliant storage, which lets health professionals access records while maintaining patient medical privacy.
Confidential Business Documents
From roadmaps to legal contracts to intellectual property, businesses have a duty to protect sensitive data. Encrypted file sharing allows file owners to share this information as needed, setting granular permissions as to who can access or modify the file.
| Use Case | Benefit |
| Remote Work Collaboration | Teams can work remotely, accessing shared documents. This addresses local security concerns (in part) and allows workers in different locations or time zones to collaborate. |
| Personal Identifiable Information and Financial Data | Encryption helps protect against identity theft and related financial losses. |
| Legal Documents and Client Communications | Encryption prevents tampering or modification while protecting confidentiality. |
| Protected Health Information | Encrypted file sharing offers a secure method for sharing private health information while complying with regulations such as HIPAA or GDPR. |
| Confidential Business Documents | Encryption helps reduce risk from corporate espionage and leaks regarding strategy or intellectual property. |
Personal Use
Outside of business use, encrypted file-sharing services already play a massive role in personal use. Ubiquitous services like Google Drive, Dropbox, and Microsoft OneDrive allow account holders to share photos, videos, documents, and more without sharing them on social media.
Methods of Encrypted File Sharing
While many of today’s file-sharing services use a similar front end for users, several approaches to secure file sharing have been used over the years.
- Client-side (end-to-end) encryption: The file is encrypted before it leaves the client device, arriving at the server in an unreadable format. Notably, the service provider cannot access the data. Examples include Proton Drive, MEGA, and the Bitwarden password manager.
- Server-side encryption: The file is encrypted after it reaches the server. This structure is more common and depends on trust in service providers, such as Google, Microsoft, or Amazon.
- Encrypted file transfer protocols: HTTPS offers the most commonly seen example of an encrypted file transfer protocol. The Hypertext Transfer Protocol Secure encrypts sensitive data between a web browser and a website. The protocol encrypts plain text data using Transport Layer Security (TLS) or Secure Sockets Layer (SSL).
- Password-protected files: One of the earliest methods of sharing files securely involved using compressed files protected with a password. Some file-sharing services still support password protection combined with other data security measures.
- Hybrid approaches: Some platforms combine two or more of the methods described above. For example, centralized services like Box or Kiteworks, or decentralized platforms like Storj or Arweave, may utilize a combination of client-side and in-transit encryption.
How to Share Encrypted Files
Most cloud storage providers today use a similar process from a user’s perspective. Let’s examine the fundamental steps involved in sharing encrypted files.
1) Choose a Provider
Find a provider or protocol that matches your needs. Well-known providers like Google and Microsoft may have access to your files, but they do offer an easy onboarding process. Providers like Proton and MEGA do not have access to your files. Decentralized options like Arweave or Storj encrypt your files before they reach the server, so only authorized users have access.
2) Set up Your Account
Follow the steps for the platform you’ve chosen. For centralized platforms, this typically requires your name, email address, and a unique password. However, this login method is more vulnerable to phishing attacks and provider-level data breaches.
3) Acquire Tokens (If Needed)
If you’ve chosen a decentralized platform, you’ll need to purchase tokens in most cases. For example, to store files on Arweave, you would use AR tokens to pay for storage. You can buy tokens through a crypto exchange that supports that specific token. After you’ve made your purchase, transfer the tokens to a supported crypto wallet so you can connect to the decentralized application (dApp) for the protocol you’ve chosen.
4) Upload Your Files
Choose which files you want to upload to the network. Use the web interface for the service to select and upload the file(s) directly from your device.
5) Manage and Share Your Files
Choose which file(s) to share and set file sharing permissions. You can manage sharing at the file or folder level, giving access to specific people, groups, or roles.
Popular Encrypted & Secure File Transfer Solutions
Most people are familiar with centralized encrypted file-sharing services like Google Drive or Dropbox. Let’s examine some of the leading decentralized file storage solutions that support file sharing.
Storj
Storj uses automatic client-side encryption, which means every file uploaded is encrypted on the user’s device before being sharded (broken into smaller parts) and distributed. These shards are stored on nodes worldwide.
To share a file, users can share a specific file key with a recipient, allowing access to just the specified file and without revealing other files or folders. The platform then utilizes client-side encryption, ensuring that only those with the encryption key can view files stored on the network.
File owners can then send the token to the recipient. With this token, the recipient can access the data using the Storj platform.
Autonomi Network (formerly SAFE Network)
Unlike many centralized cloud storage providers, Autonomi utilizes self-encryption, meaning all data is encrypted before it reaches the platform’s storage nodes. The encryption keys are derived from the data itself, and the data is divided into shards before being distributed to nodes.
Files on Autonomi are better described as data maps that point to the individual chunks stored on nodes. The only keys remain on the user’s device.
Sharing occurs by sending the data map and encryption keys to another recipient using a secure messaging app or other secure means. Although private by default, users can opt to make files or folders public.
Sia
Client-side encryption ensures that only encrypted data reaches Sia’s nodes. The platform uses sharding to distribute chunks of data to its network, ensuring no single node has all the pieces needed to reconstruct the file.
User-managed “siafiles” hold the metadata, including where the file shards are held and the encryption keys. These siafiles can be shared with intended recipients via secure channels, such as messaging apps with end-to-end encryption.
A growing assortment of apps makes this process even easier. For example, Vup, a cloud storage app built on top of Sia’s infrastructure, allows users to send files easily with permissioned access and a secure link.
Züs Network (formerly 0chain):
Like other decentralized file storage platforms, Züs uses client-side encryption to ensure hosts (called Blobbers) can’t read or assemble file contents independently. Users have control over the number of shards used and their distribution.
Where Züs stands out is in its Proxy Re-Encryption. This allows users to generate a second re-encryption key. This key is then sent to Blobbers, which can decrypt the data without needing to see the data itself. Züs offers more fine-grained access control and provides a user-friendly way for recipients to view shared files. Access can be granted with a single click.
Arweave
While best known for its permanent storage (permaweb), Arweave can also be used as a capable encrypted file-sharing platform. By default, data on Arweave is public. However, with ArDrive, a popular app built atop the Arweave Protocol, users can store data privately.
The Arweave File System (ArFS) is at the heart of file sharing and is also used to generate encryption keys. To share a file, users can share a specific file key with a recipient, allowing access to just the specified file and without revealing other files or folders. The platform uses client-side encryption to ensure only those with an encryption key can view files stored on the network.
Conclusion
Encrypted file sharing isn’t new; the concept has been around since the 1990s, with the introduction of PGP (Pretty Good Privacy), which uses asymmetric encryption (two keys). However, since these early roots, encrypted file sharing has become a key feature in the cloud storage industry, generating an estimated revenue of more than $135 billion as a whole.
Decentralized encrypted file-sharing services bring a new level of privacy compared to many centralized solutions, although they also come with a learning curve. These newer platforms utilize blockchain technology to determine who owns files, where they are stored, and who has access to them. Despite the small learning curve, businesses and individuals are increasingly moving to decentralized options for privacy, censorship resistance, and, oftentimes, lower costs.
References
- National Public Data breach publishes private data of 2.9B US citizens (ibm.com)
- Summary of the HIPAA Security Rule (hhs.gov)
- Content-Addressable Storage (autonomi.com)
- See what powers the Sia network. (sia.tech)
- ArDrive (ardrive.io)
FAQs
What is the most secure file sharing?
Decentralized platforms like Arweave, Storj, and Züs offer the most secure solutions. These protocols encrypt the data locally before upload and split the data into shards that are distributed throughout the network. This prevents any single host from decrypting the data. Users can share data with confidence that only those with an encryption key can access it.
How to encrypt files before sharing?
Users can encrypt files locally using compression applications or encryption apps that generate a shareable key file. However, many decentralized storage applications use client-side encryption that encrypts data before it reaches the network.
Is OneDrive secure file sharing?
Microsoft’s OneDrive uses AES-256 encryption to encrypt files, making them unreadable in transit and at rest (on the server). However, Microsoft retains the encryption keys, and the platform uses a standard username/password login, which may be less secure than decentralized options.
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