Unlimited File Transfer: The BYOS Architecture That Removes Every Size Limit

The 200 GB Problem

Every consumer and prosumer file sharing service you have ever used imposes a file size limit, and the reason is not technical — it is economic. When Dropbox, WeTransfer, or Google Drive stores your file, they are paying for that storage on hardware they own and operate in data centers they lease. Storage costs money. Bandwidth costs money. As file sizes grow from megabytes to gigabytes to terabytes, those costs scale linearly, and the business model that worked for a 100 MB presentation slides begins to buckle under a 100 GB video export. The result is a patchwork of limits designed to keep average storage cost per user manageable: WeTransfer caps free transfers at 2 GB and paid tiers at 200 GB. Dropbox's largest business plan allows files up to 10 TB in theory, but only because they are betting most users never actually hit that ceiling.

For teams operating at the frontier of data-heavy workflows, these limits are not inconveniences — they are blockers. A machine learning research team shipping Llama 3 70B model weights between a training cluster and a production inference server is dealing with 40+ GB artifacts. A post-production studio receiving RAW 8K footage from a field crew shoots 100–800 GB per project day. A genomics company performing whole-genome sequencing produces FASTQ files in the 50–200 GB range per patient sample. A satellite imagery platform distributing geospatial tiles to analysis agents may handle 1 TB+ per dataset. For these teams, "just use Google Drive" is the same as saying "just don't share the file."

The fundamental architectural reason consumer file sharing services hit walls at large sizes is that they act as the storage layer. They own the files between upload and download. This is convenient for the user experience — no configuration required, just drag and drop — but it creates an irreconcilable conflict between their cost structure and your file size. ShareBolt's approach flips the ownership model entirely. ShareBolt is not a storage service. It is a cryptographic coordination service — and that distinction is what makes unlimited file transfer possible.

What Is Bring Your Own Storage (BYOS)?

Bring Your Own Storage means exactly what it says: you bring your own cloud storage bucket, and ShareBolt encrypts your file and writes the encrypted data directly there. Currently, ShareBolt BYOS supports Cloudflare R2; support for AWS S3, Azure Blob Storage, Google Cloud Storage, and MinIO is planned. ShareBolt generates an AES-256-GCM encryption key locally on your device, encrypts the file before it leaves your machine, and uploads the encrypted data directly to your bucket using your storage credentials. ShareBolt's servers handle only the encrypted key envelope — the tiny piece of data (a few hundred bytes) needed to let the recipient unwrap the decryption key.

This architecture removes two constraints simultaneously. First, it dramatically increases the size ceiling: Pro Vault supports up to 25 GB per file with BYOS; Enterprise Citadel supports unlimited file sizes with BYOS. Second, it removes the custody problem: your data never resides on ShareBolt's infrastructure, which means ShareBolt cannot be compelled to produce your files in a legal discovery request, cannot be breached in a way that exposes your file contents, and cannot go bankrupt and delete your data. You are always in possession of your own encrypted data.

BYOS Architecture: The Complete Data Flow

Here is exactly what happens when you initiate a large file transfer with BYOS enabled — every step, in order:

The encryption design processes the file before it leaves your device. Each chunk is encrypted independently with the same AES-GCM key but a unique nonce, then uploaded to your storage backend. (Note: single-part uploads are currently supported. Chunked resumable uploads are on the roadmap.) Pro Vault supports up to 25 GB per file with BYOS; Enterprise Citadel supports unlimited file sizes with BYOS.

Supported Storage Backends

BYOS is available on Pro Vault and Enterprise plans. Currently Cloudflare R2 is the supported BYOS backend. S3, Azure Blob, GCS, and MinIO support are planned for future releases.

Cloudflare R2 is the currently supported BYOS backend. R2 charges zero egress fees when files are downloaded through Cloudflare's network, which is the path ShareBolt uses for pre-signed download URLs. For large file transfer workloads that involve frequent downloads — like a CI/CD pipeline pulling model artifacts on every training run — this can result in significant cost savings. AWS S3, Azure Blob, GCS, and MinIO (for on-premises air-gapped deployments) are planned as future BYOS backends.

Real-World Large File Transfer Scenarios

The following are representative workloads from teams currently using ShareBolt BYOS in production:

• 🧠
  AI Model Weights Distribution

  A research lab ships Llama 3 70B model weights from their training cluster to a production inference service after each fine-tuning run. The checkpoint includes optimizer state, which pushes the total to ~80 GB per transfer. With BYOS to an S3 bucket in the same region as the inference cluster, transfer completes in 12–18 minutes at full network bandwidth.

  ~40–80 GB per transfer
• 🎬
  RAW 8K Video Post-Production

  A field production crew shoots RAW 8K footage for a commercial campaign. At the end of each shoot day, the DIT uploads the day's rushes directly to the post-production studio's R2 bucket — no hard drive courier, no FTP server setup. The studio's colorist receives a ShareBolt notification and begins grade immediately.

  100–800 GB per project
• 🏥
  Medical Imaging DICOM Archives

  A radiology network transfers whole-body PET-CT DICOM archives between imaging centers and specialist consultants. HIPAA requires both encryption in transit and at rest, plus an audit trail for every access. ShareBolt's client-side encryption and ledger provide both, with BYOS keeping the data in the healthcare organization's own HIPAA-compliant S3 environment.

  50–200 GB per study
• 🗄️
  Database Exports and ETL Dumps

  A fintech platform runs nightly cross-region data pipeline syncs, exporting PostgreSQL logical replication dumps and Parquet fact tables from production to an analytics replica in a separate cloud region. ShareBolt BYOS handles the transfer with chunked resumable uploads, so a brief network interruption does not require restarting a 200 GB export from scratch.

  10–500 GB per sync
• 🛰️
  Satellite Imagery Distribution

  A geospatial analytics platform distributes high-resolution multispectral satellite imagery tiles to dozens of downstream AI analysis agents. Each tile set for a region of interest can exceed 1 TB. BYOS with a GCS multi-region bucket allows all agents in the platform to pull from the same encrypted source, with ShareBolt managing per-agent key envelopes.

  1 TB+ per dataset

Setting Up BYOS in 5 Minutes

Connecting your AWS S3 bucket to ShareBolt requires only a minimal IAM policy and a 5-minute configuration in your dashboard:

• Log in to your ShareBolt dashboard at Pro Vault or higher. BYOS is available from the Pro Vault tier upward.
• Navigate to Settings → Storage Backends and click + Add Backend. Select your provider (currently Cloudflare R2; S3, Azure Blob, GCS, and MinIO are planned).
• Enter your bucket name, region, and IAM access key. ShareBolt's IAM policy requires only three S3 actions — no administrative permissions needed. Use the minimal policy below.
• ShareBolt validates write permissions automatically by uploading and immediately deleting a small test object in a .sharebolt-probe/ prefix. If validation succeeds, the backend is live.
• Start transferring. All new file transfers will automatically route through your bucket. Existing transfers on ShareBolt Managed storage are unaffected unless you explicitly migrate them.

Use this minimal IAM policy — ShareBolt requires only the three S3 actions needed to write, serve, and clean up encrypted file chunks:

{
  "Version": "2012-10-17",
  "Statement": [
    {
      "Effect": "Allow",
      "Action": [
        "s3:PutObject",
        "s3:GetObject",
        "s3:DeleteObject"
      ],
      "Resource": "arn:aws:s3:::my-sharebolt-transfers/*"
    }
  ]
}

Do not grant s3:* or s3:ListBucket to the ShareBolt IAM user. Least-privilege is especially important here because the IAM credentials are stored locally in the ShareBolt client and never sent to ShareBolt's servers — but scoping permissions tightly limits the blast radius if the local device is ever compromised.

Security: Your Data, Your Keys, Your Bucket

BYOS does not just solve the size limit problem — it delivers a fundamentally stronger security posture than centrally-stored file transfer services. The threat model is different in every dimension:

This security model means that for teams operating under HIPAA, GDPR, FedRAMP, or ISO 27001, BYOS is often the only architecturally acceptable option. When auditors ask "where does our data live?", the answer is simple: in your own cloud account, encrypted with keys that only your authorized users hold, never touching a third-party's storage layer. ShareBolt is not a data processor for your files under GDPR — it is a communications relay for cryptographic envelopes. That distinction can meaningfully simplify your compliance posture.