Skip to content

Device-Revocation-Sequence.md

Latest commit

 

History

History
88 lines (68 loc) · 3.55 KB

Device-Revocation-Sequence.md

File metadata and controls

88 lines (68 loc) · 3.55 KB
Raw

Device Revocation Sequence Diagram

This diagram shows the complete flow of revoking a compromised or lost device in LibEmiddle's multi-device architecture.

sequenceDiagram
    participant UserPrimary as User (Primary Device)
    participant PrimaryLib as LibEmiddle (Primary)
    participant Server as Transport Server
    participant OtherDevices as Other User Devices
    participant Contacts as User Contacts

    Note over UserPrimary, Contacts: Device Revocation Process

    UserPrimary->>PrimaryLib: Request device revocation
    PrimaryLib->>PrimaryLib: DeviceManager.CreateDeviceRevocationMessage()
    PrimaryLib->>PrimaryLib: Sign revocation with identity key
    
    PrimaryLib->>Server: Send revocation message
    Server->>OtherDevices: Deliver revocation
    OtherDevices->>OtherDevices: DeviceManager.ProcessRevocationMessage()
    OtherDevices->>OtherDevices: Mark device as revoked

    Note over UserPrimary, Contacts: Security Key Rotation

    PrimaryLib->>PrimaryLib: Create new identity key bundle
    PrimaryLib->>Server: Upload new key bundle
    PrimaryLib->>Server: Send revocation to contacts
    
    Server->>Contacts: Deliver revocation notice
    Contacts->>Contacts: Update contact key material
    Contacts->>Contacts: Mark sessions with old device for re-initialization

    Note over UserPrimary, Contacts: Group Security Update

    PrimaryLib->>PrimaryLib: Rotate all group keys
    PrimaryLib->>Server: Upload new group keys
    Server->>OtherDevices: Update group keys
    Server->>Contacts: Update group keys
Loading

Key Components

Device Revocation Management

  • DeviceManager: Handles device lifecycle and revocation processes
  • Cryptographic Signatures: Revocation messages signed with identity keys
  • Distributed Notification: All affected parties notified of revocation

Security Measures

  1. Immediate Isolation: Revoked device marked as untrusted across network
  2. Key Rotation: All identity and session keys regenerated
  3. Contact Notification: All contacts informed of device revocation
  4. Group Key Updates: All group conversations get new encryption keys

Revocation Process Flow

Phase 1: Device Revocation

  • User initiates revocation from trusted device
  • Cryptographically signed revocation message created
  • All user's other devices notified and mark device as revoked

Phase 2: Key Material Rotation

  • Primary device generates new identity key bundle
  • New keys uploaded to replace compromised keys
  • Contacts receive notification of key material changes

Phase 3: Session Re-establishment

  • Contacts mark old sessions for re-initialization
  • New sessions established using fresh key material
  • All group memberships updated with new keys

Security Benefits

  • Forward Secrecy: Past messages remain secure even if device compromised
  • Post-Compromise Security: New messages secure after revocation
  • Network Effect: Revocation propagates to all connected parties
  • Granular Control: Individual device revocation without affecting others

Recovery Scenarios

  • Lost Device: Immediate revocation prevents unauthorized access
  • Stolen Device: Remote revocation invalidates all sessions
  • Compromised Device: Key rotation ensures future security
  • Planned Replacement: Controlled migration to new device

Implementation Notes

  • Revocation messages include timestamp and device identifier
  • Cryptographic proof prevents spoofed revocation requests
  • Grace period may apply for temporary connectivity issues
  • Emergency revocation available through out-of-band channels