SecureSend vs WeTransfer: What Really Happens to Your Files

WeTransfer is one of the most popular file-sharing services in the world, with over 80 million monthly users. Its appeal is obvious: drag a file, get a link, send it. No friction. But convenience often comes at the cost of privacy. What actually happens to your files once you upload them?

This article compares WeTransfer's architecture with SecureSend's zero-knowledge approach, based on publicly available documentation and privacy policies.

What WeTransfer Does with Your Files

WeTransfer encrypts files in transit (TLS) and at rest on their servers. This is standard practice and protects against external attackers. However, WeTransfer holds the encryption keys. This means:

• WeTransfer can decrypt and access your files. Their privacy policy states they may access content "to provide, maintain and improve our services."
• Files are stored for 7 days (free) or longer (paid). During this period, your unencrypted data exists on WeTransfer's infrastructure.
• Content is scanned. WeTransfer scans uploads for malware and prohibited content. Scanning requires reading the file.
• Third-party processors. WeTransfer uses AWS for hosting. Your data passes through (and is stored on) Amazon's infrastructure.
• Legal requests. If a government agency issues a valid legal request, WeTransfer can provide your files in readable form because they possess the decryption keys.

What SecureSend Does Differently

SecureSend uses a fundamentally different architecture. Files are encrypted in the browser using AES-256-GCM before they are uploaded. The encryption key is placed in the URL fragment (the # portion), which is never sent to the server per the HTTP specification.

The server receives and stores only encrypted data. It does not have the key and cannot decrypt the file. Even if an attacker compromises the server or a government issues a subpoena, only meaningless encrypted bytes can be produced.

Side-by-Side Comparison

The File Size Trade-Off

The most obvious advantage WeTransfer has is file size. You can send up to 2 GB for free and 200 GB with a paid plan. SecureSend supports 1 MB on the free plan and 10 MB on Pro. These are different tools for different purposes.

WeTransfer is designed for large media files — video projects, design assets and photo collections. SecureSend is designed for sensitive documents — contracts, tax forms, identity documents, medical records and financial statements. Most sensitive documents are well under 1 MB.

Password Protection Is Not End-to-End Encryption

WeTransfer Pro offers password-protected transfers. This sounds similar to encryption but is fundamentally different. The password protects access to the download page — it does not encrypt the file itself. WeTransfer's servers still store and can access the unencrypted file. The password is simply an access gate, not an encryption key.

With SecureSend, the "password" is the AES-256 encryption key embedded in the URL. Without it, the file is a block of random bytes. There is no access gate because there is nothing readable to gate access to.

What Happens During a Data Breach

Data breaches at file-sharing services are not hypothetical. WeTransfer itself suffered a security incident in 2019 where files were sent to the wrong recipients. In a server-side encryption model, a breach exposes readable files because the keys are on the same infrastructure.

Metadata Considerations

Even with zero-knowledge encryption, some metadata is visible to the server: the sender's IP address, the file size, timestamps and the number of downloads. SecureSend does not know the file name (it is encrypted along with the content) or the file type.

WeTransfer, by contrast, knows everything: file names, file types, sender email, recipient email, the message you attached and the full file contents.

When to Use Which

Use WeTransfer when:

• You are sharing large media files (videos, design assets) that are not sensitive
• You need to transfer gigabytes of data quickly
• Privacy is not a concern for the specific content

Use SecureSend when:

• The file contains personal, financial, medical or legal information
• You need to comply with GDPR, HIPAA or similar regulations
• You want the file to disappear after download (single-use)
• You need to control exactly how long the file is accessible
• You do not want any third party — including the server operator — to read your files

The Verdict

WeTransfer and SecureSend serve different purposes. WeTransfer is a convenience tool for large, non-sensitive files. SecureSend is a security tool for sensitive documents where privacy is non-negotiable. The key difference is architectural: WeTransfer's servers can read your files; SecureSend's server cannot. That distinction matters every time you share something confidential.