```mermaid
flowchart TD
A[Start concurrent_fetch] --> B[Clone entries]
B --> C[For each entry]
C --> D[Spawn tokio task]
D --> E[Handle entry concurrently]
E --> F{Entry in DB?}
F -->|Yes| G{Value changed?}
F -->|No| H[Fetch from URL]
G -->|Yes| H
G -->|No| I[Log cache hit]
H --> J[Encrypt data]
J --> K[Store in DB]
I --> L[End task]
K --> L
L --> M{All tasks complete?}
M -->|No| C
M -->|Yes| N[End concurrent_fetch]
```
