API

Seal files and retrieve proof from your terminal or application.

Base URL: https://soulprop.com

100 MB

max file size

seals per day

7 years

storage retention

Quick start

Seal a file, save your key, and reveal it later. Three commands.

1. Seal a file

Upload any file. You get back a seal ID, encryption key, and RFC 3161 timestamp.

curl -X POST https://soulprop.com/api/seal \
  -F "file=@document.pdf"

Response:

{
  "id": "ABC12345",
  "fingerprint": "a1b2c3d4e5f6...",
  "key": "base64-encoded-32-byte-key",
  "timestamp": "2026-01-04T12:00:00Z",
  "verifyUrl": "https://soulprop.com/s/ABC12345",
  "keyFile": { ... }
}

2. Save your key

The key field is your decryption key. We don't store it. If you lose it, your file is gone. Save the response to a .soulprop file:

curl -s -X POST https://soulprop.com/api/seal \
  -F "file=@document.pdf" \
  | jq '.keyFile' > document.soulprop

3. Reveal later

When you need proof, decrypt with your key and download the original file.

# Get your original file back
curl -X POST https://soulprop.com/api/seal/ABC12345/reveal \
  -H "Content-Type: application/json" \
  -d '{"key": "your-base64-key"}' \
  -o revealed_document.pdf

# Download court-ready evidence package
curl -X POST https://soulprop.com/api/seal/ABC12345/evidence \
  -H "Content-Type: application/json" \
  -d '{"encryption_key": "your-base64-key"}' \
  -o evidence.zip

Endpoints

POST /api/seal

Upload and seal a file. Returns seal metadata and your encryption key.

Request

Content-Type: multipart/form-data

Field	Type	Description
`file` required	file	The file to seal (max 100 MB)

Response

Field	Type	Description
`id`	string	8-character seal ID
`fingerprint`	string	SHA-256 hash of the sealed content
`key`	string	Base64-encoded 32-byte encryption key. Save this.
`timestamp`	string	ISO 8601 UTC timestamp from the TSA
`verifyUrl`	string	Public URL to verify this seal
`keyFile`	object	Ready-to-save key file contents

GET /api/seal/{id}

Get public metadata for a seal. No authentication required.

curl https://soulprop.com/api/seal/ABC12345

Response

Field	Type	Description
`id`	string	Seal ID
`fingerprint`	string	SHA-256 hash
`timestamp`	string	When the seal was timestamped
`originalSize`	number	Original file size in bytes
`revealed`	boolean	Whether this seal has been revealed

POST /api/seal/{id}/reveal

Decrypt a sealed file with your encryption key. Returns the original file.

Request body

Content-Type: application/json

Field	Type	Description
`key` required	string	Base64-encoded 32-byte encryption key

curl -X POST https://soulprop.com/api/seal/ABC12345/reveal \
  -H "Content-Type: application/json" \
  -d '{"key": "your-base64-key"}' \
  -o original_file.pdf

POST /api/seal/{id}/evidence

Download a court-ready evidence package as a ZIP file.

Request body

Field	Type	Description
`encryption_key` required	string	Base64-encoded 32-byte encryption key

Evidence package contents

original.* Your decrypted original file

certificate.pdf Human-readable PDF certificate with seal details

timestamp.tsr RFC 3161 timestamp token from FreeTSA

verify.sh OpenSSL script to independently verify the timestamp

curl -X POST https://soulprop.com/api/seal/ABC12345/evidence \
  -H "Content-Type: application/json" \
  -d '{"encryption_key": "your-base64-key"}' \
  -o evidence.zip

# Verify the timestamp independently
unzip evidence.zip -d evidence/
cd evidence && bash verify.sh

Errors

All errors return JSON with error and code fields.

{ "error": "descriptive message", "code": "ERROR_CODE" }

Code	HTTP	Meaning
`MISSING_FILE`	400	No file in the multipart request
`FILE_TOO_LARGE`	413	File exceeds 100 MB limit
`DAILY_LIMIT_REACHED`	429	3 seals per day limit reached
`RATE_LIMITED`	429	Too many requests (60/min)
`SEAL_NOT_FOUND`	404	Seal ID doesn't exist
`WRONG_KEY`	400	Decryption key doesn't match
`TIMESTAMP_UNAVAILABLE`	503	TSA temporarily unavailable, retry

Seal and save your key in one line

curl -s -X POST https://soulprop.com/api/seal -F "file=@yourfile" | jq '.keyFile' > yourfile.soulprop