DAT Python Library
GitHub PyPIInstallation
Quick start
This complete flow retrieves certificates from CMS, creates a DAT containing JSON data, and verifies it.
Step by step
1. Connect to CMS
An issuing service uses a token for full certificates. Synchronizing immediately at startup prevents issuance before certificates are available.
2. Issue a DAT
This example puts public JSON in plain and protected user information as JSON in secure.
3. Verify a DAT
parse checks expiration and the signature, then decrypts secure. Use only a payload returned after successful verification.
Key functions
| Function | Purpose |
|---|---|
sync_or_raise() | Synchronizes certificates immediately. |
issue(plain, secure) | Creates a DAT string. |
parse(dat) | Verifies a DAT and returns a DatPayload. |
last_error() | Returns the last synchronization error. |
Data regions
plain: bytes that are signed but not encrypted.secure: encrypted bytes.payload: trust it only afterparsesucceeds.
Options beyond JSON
The examples use familiar JSON. For faster processing, binary data can avoid JSON serialization and parsing while reducing data size.
Store simple values as text, or place structured data in binary formats such as Protobuf or MessagePack in plain and secure.
Pass bytes directly and retrieve them through plain_bytes and secure_bytes.
Verify-only services
A service that does not issue DATs uses the verify-only option and a verify-only token, and calls only parse.
Shutdown and errors
When automatic synchronization is enabled, call stop() at shutdown.
Use error codes and retry classifications instead of error messages.