docs: add short Security & data section (HTTPS, encryption at rest)

Co-authored-by: Cursor <cursoragent@cursor.com>

Author: uzunenes

README.md

@@ -132,6 +132,10 @@ health = client.health()
 print(health["status"])  # "ok"
 ```
 
+### Cache
+
+The API caches by content (model + prompt + size). Repeat the same request to get a cache hit (`result.cache_hit == True`, lower latency and cost). See `examples/07_cache_demo.py`.
+
 ## Async Client
 
 ```python
@@ -186,6 +190,10 @@ with Client() as client:
 | `replicate_key` | `None` | Replicate BYOK key |
 | `runway_key` | `None` | Runway BYOK key |
 
+## Security & data
+
+All API traffic uses HTTPS. Provider API keys (BYOK) are encrypted at rest; other account and usage data is stored on Google Cloud with encryption at rest. See the [API docs](docs/API.md) for more.
+
 ## Examples
 
 See the [`examples/`](examples/) directory for tested scripts covering every SDK feature:
@@ -201,6 +209,7 @@ See the [`examples/`](examples/) directory for tested scripts covering every SDK
 | `04_videos_all_providers.py` | Video generation | Yes |
 | `05_usage_history_verify.py` | Usage, logs, and dashboard | Yes |
 | `06_provider_balances.py` | Provider status and balances | Yes |
+| `07_cache_demo.py` | Cache: two identical image requests | Yes |
 
 ```bash
 # Run all examples in order

docs/API.md

@@ -416,6 +416,10 @@ print(f"Image: {result.image_url}")
 client.close()
 ```
 
+## Security & data
+
+API traffic is over HTTPS. Provider keys (BYOK) are encrypted at rest; account and usage data are stored on Google Cloud with encryption at rest.
+
 ## Additional Resources
 
 - SDK README: [README.md](../README.md)