Rapidlynk

Rapidlynk is a high-performance, zero-knowledge CLI for bundling, encrypting, and sharing project directories securely. Rapidlynk uses AWS API Gateway, AWS Lambda, and Amazon S3 for the backend. Project files are encrypted locally before they are uploaded, and the actual file transfer happens directly between the CLI and Amazon S3 using short-lived presigned URLs.

---

How It Works

Push

rapidlynk push
      │
      ▼
Bundle project (tar.gz)
      │
      ▼
Encrypt locally (AES-256-GCM → project.enc)
      │
      ▼
POST /api/upload-url
      │
      │ { filename, size }
      ▼
API Gateway
      │
      ▼
AWS Lambda
      │
      ▼
Generate S3 Presigned POST
      │
      │ { fileId, url, fields }
      ▼
CLI
      │
      │ multipart/form-data
      ▼
Amazon S3
      │
      ▼
CLI displays secret <file_id>:<encryption_key>

Pull

rapidlynk pull <file_id>:<key>
      │
      ▼
POST /api/download-url/<file_id>
      │
      ▼
API Gateway
      │
      ▼
AWS Lambda
      │
      ▼
Generate S3 Presigned GET URL
      │
      ▼
CLI
      │
      │ Download encrypted file
      ▼
Amazon S3
      │
      ▼
Decrypt locally (AES-256-GCM)
      │
      ▼
Extract project

---

Security Model

Rapidlynk follows a zero-knowledge approach for project contents:

• Client-Side Encryption: Projects are encrypted locally on the user's machine using AES-256-GCM.
• No Shared Secrets with Server: The encryption key is never sent to the backend.
• Metadata Only: The backend only handles the encrypted file and file metadata.
• Encrypted Storage: File contents are stored in Amazon S3 strictly in encrypted form.
• Presigned URLs: S3 upload and download access uses short-lived presigned URLs.

The sharing secret contains the file ID and encryption key:

<file_id>:<encryption_key>

Anyone with this secret can retrieve and decrypt the shared project, so it should be treated as sensitive.

---

How to Use

Prerequisites

For development/building the CLI:

• Go 1.22+
• Node.js and npm for npm distribution

Note: End users installing Rapidlynk through npm do not need Go installed.

Build the CLI

From the project root:

go build -o rapidlynk.exe ./cli

On Windows:

.\rapidlynk.exe --help

On Linux/macOS:

./rapidlynk --help

---

Push a Project

Run rapidlynk push from the root directory of the project you want to share:

rapidlynk push

Rapidlynk will:

1. Bundle the project into a tar.gz archive.
2. Encrypt the archive locally using AES-256-GCM.
3. Request an S3 upload URL from the AWS backend.
4. Upload the encrypted file directly to Amazon S3.
5. Display a sharing secret.

Example Output:

📦 Bundling project...
🔒 Encrypting with AES-256-GCM...
☁️ Requesting upload URL from AWS Lambda...
🚀 Uploading project.enc directly to Amazon S3...

✅ Upload complete! Share this secret:
----------------------------------------
7fff765f8f40865fe377b8bbb047666d:GFe5LmnPeJfkJ4bRQYAizrgl0reokQa1ILRCsMdj8yQ=
----------------------------------------

Share the generated secret with the recipient.

---

Pull a Project

The recipient can retrieve the project using the secret:

rapidlynk pull <file_id>:<encryption_key>

Example:

rapidlynk pull 7fff765f8f40865fe377b8bbb047666d:GFe5LmnPeJfkJ4bRQYAizrgl0reokQa1ILRCsMdj8yQ=

Rapidlynk will:

1. Request a short-lived download URL from AWS Lambda.
2. Download the encrypted project directly from Amazon S3.
3. Decrypt the project locally.
4. Extract the project files.

---

AWS Backend Architecture

Rapidlynk uses a serverless AWS backend:

┌─────────────────┐
│    Rapidlynk    │
│       CLI       │
└────────┬────────┘
         │ HTTPS / JSON API
         ▼
┌─────────────────────┐
│     API Gateway     │
│      HTTP API       │
└──────────┬──────────┘
           │
           ▼
┌─────────────────────┐
│     AWS Lambda      │
│  Hono / TypeScript  │
└──────────┬──────────┘
           │ Generate presigned S3 URLs
   ┌───────┴───────┐
   │               │
   ▼               ▼
Presigned POST  Presigned GET
   │               │
   ▼               ▼
┌─────────────────────────────────────┐
│              Amazon S3              │
│                                     │
│          bundles/<file_id>          │
└─────────────────────────────────────┘

Control Plane

The CLI communicates with the backend through API Gateway:

CLI → API Gateway → Lambda

The backend is responsible for:

• Generating file IDs
• Generating S3 presigned upload requests
• Generating S3 presigned download URLs
• Recording download/upload metrics

Data Plane

The actual encrypted file transfer does not pass through Lambda:

CLI → S3
S3 → CLI

This keeps the Lambda/API Gateway layer out of the large file-transfer path.

---

API Endpoints

Generate Upload URL

POST /api/upload-url

Request:

{
  "filename": "project.enc",
  "size": 123456
}

The backend returns an S3 presigned POST containing:

• url
• fileId
• signed fields

The CLI then uploads the encrypted file directly to S3.

Generate Download URL

GET /api/download-url/:id

The backend generates a short-lived S3 presigned GET URL. The CLI uses that URL to download the encrypted project directly from S3.

---

NPM Distribution

Rapidlynk is distributed through npm with pre-compiled platform-specific binaries.

Install Globally

npm install -g rapidlynk

Or Run Directly via npx

npx rapidlynk --help

The npm package automatically selects the appropriate binary based on the user's operating system and CPU architecture.

Supported Platforms

Platform	Architecture
Windows	x64
Windows	ARM64
Linux	x64
Linux	ARM64
macOS	x64 (Intel)
macOS	ARM64 (Apple Silicon)

For developer build and release instructions, see PUBLISHING.md.

---

Development

Clone the repository:

git clone https://github.com/Galactic-git/rapidlynk.git
cd rapidlynk

Build the CLI:

go build -o rapidlynk.exe ./cli

Run:

.\rapidlynk.exe --help

---

License

Rapidlynk is released under the MIT License.