1. FIPS Compliance Guide
  2. Finite State Machine

4 Finite State Machine

As part of FIPS 140-2 Level 2 compliance, the Acme Packet 1100 and Acme Packet 3900 platforms support a Finite State Machine (FSM).

The following Diagram displays the state model of the FSM in the FIPS 140-approved mode of operation:

The Finite State Machine diagram displays the state model of the FSM in the FIPS 140-approved mode of operations.

State Diagram

The following sections describe all states and transitions that can occur with the Finite State Diagram. The finite state machine never ends in an undefined state. Any combination of data and control inputs always place the FSM in a well-defined state.

Note:

The inputs described in this document for each state are inputs that would result in a successful operation.

State 0 - Power Off

Either the power switch is in the off position, or there is no power connected to the FSM. No services are available in this state. This state is available from every other state, and can be entered using the power switch and cycling power.
Transition Number Transition Next State
01a Module is powered on 0a
Data Input None N/A
Data Output None N/A
Control Input Connect Power Supply N/A
Status Output LED - power N/A

State 0a - Power On

The FSM's power switch is turned on. No services are available in this state. The FSM automatically transitions to the Power-On Self-Tests state.
Transition Number Transition Next State
01b Begin boot 1
Data Input None N/A
Data Output None N/A
Control Input Power switch on N/A
Status Output LED - power N/A

State 1 - Power-On Self-Tests

The FSM performs a series of self-tests to ensure correct operation; these include a software integrity check, cryptographic known answer tests, and other self-tests described in the Security Policy. If the POSTs are successful, the module continues to boot, and this state automatically transfers to the "No Auth" state. If the POSTs should fail, the module transitions to the "Error" state.
Transition Number Transition Next State
13 Self Tests Pass 3
Data Input None N/A
Data Output None N/A
Control Input None N/A
Status Output Initial login prompt N/A
12 POST Failure 2
Data Input None N/A
Data Output None N/A
Control Input None N/A
Status Output Error logged N/A
20 Power Switch to Off/Reboot 0
Data Input None N/A
Data Output None N/A
Control Input Disconnect Power Supply N/A
Status Output None / Display boot status on startup N/A

State 2 - Error

This state represents an error, such as a POST failure or Conditional Self-Test Failure. The FSM halts cryptographic operations and the operator must use any of the 3 possible recovery options:
  • Reset the FSM
  • Reset the FSM and use the bootloader to select the valid image
  • Reset the FSM and use the bootloader to zeroize the system to RMA
Transition Number Transition Next State
20 Power Switch to Off/Reboot 0
Data Input None N/A
Data Output None N/A
Control Input Disconnect Power Supply N/A
Status Output None / Display boot status on startup N/A

State 3 - No Auth

The FSM transitions to this state when startup has completed and the module is fully configured for FIPS mode of operation. In this state no User or Crypto Officer is logged in, and the module is in an idle state. The FSM is operational but is not providing security services or performing cryptographic functions. Cryptographic keys and security parameters are loaded, and the FSM is waiting for data or control inputs. The FSM transitions to the User state when a User is successfully authenticated or it transitions to the Crypto Officer state when a Crypto Officer is successfully authenticated.
Transition Number Transition Next State
34 User Login 4
Data Input User or SSH public key N/A
Data Output Acceptance / Denial of Authentication Attempt N/A
Control Input Authentication Data N/A
Status Output User Authentication Prompt N/A
35 Crypto Officer Login 5
Data Input Crypto Officer Authentication Data N/A
Data Output Acceptance / Denial of Authentication Attempt N/A
Control Input Authentication Data N/A
Status Output Crypto Officer Authentication Prompt N/A
30 Power Switch to Off/Reboot 0
Data Input None N/A
Data Output None N/A
Control Input Disconnect Power Supply N/A
Status Output None / Display boot status on startup N/A
02 Conditional Test Failure 2
Data Input None N/A
Data Output None N/A
Control Input None N/A
Status Output Error logged N/A

State 4 - User

The FSM transitions into this state when a User authenticates to the module or when an encrypted session has been initiated. After successful login, the User has access to the services defined in the Roles, Services, and Authentication section of the Security Policy.
Transition Number Transition Next State
43 User Logoff 3
Data Input None N/A
Data Output None N/A
Control Input Initiate Log Off N/A
Status Output Logoff confirmation N/A
47 Initial Bypass 7
Data Input Call from endpoint configured for plaintext received N/A
Data Output Plaintext call output N/A
Control Input Endpoint Configuration N/A
Status Output Call Successful N/A
30 Power Switch to Off/Reboot 0
Data Input None N/A
Data Output None N/A
Control Input Disconnect Power Supply N/A
Status Output None / Display boot status on startup N/A
02 Conditional Test Failure 2
Data Input None N/A
Data Output None N/A
Control Input None N/A
Status Output Error logged N/A

State 5 - Crypto Officer

This state is entered when an operator successfully authenticates as a Crypto Officer. A Crypto Officer may configure the FSM as defined in the Secure Operation section of the Security Policy. A Crypto Officer can re-enter the No Auth state by logging out. The Crypto Officer may return to Power On Self Tests state by rebooting the software. Physically removing power from the module will return it to the Power Off state. The Crypto Officer can transition to the Edit Configuration state to edit the running configuration and manipulate keys.
Transition Number Transition Next State
56 Initiate Configuration Edit 6
Data Input Configuration Parameters N/A
Data Output None N/A
Control Input Configuration Parameters N/A
Status Output Configuration Verifications N/A
53 Crypto Officer Logoff 3
Data Input None N/A
Data Output None N/A
Control Input Initiate Log Off N/A
Status Output Logoff confirmation N/A
50 Power Switch to Off/Reboot 0
Data Input None N/A
Data Output None N/A
Control Input Disconnect Power Supply N/A
Status Output None / Display boot status on startup N/A
02 Conditional Test Failure 1
Data Input None N/A
Data Output None N/A
Control Input None N/A
Status Output None N/A

State 6 - Edit Configuration

This state is entered from the Crypto Officer state with various commands to configure the FSM and enter cryptographic keys. Only a Crypto Officer may edit the configuration of the FSM. Once the configuration is complete, the new configurations are effective immediately once the configuration is activated. The FSM returns to the Crypto Officer state when the Crypto Officer has completed configuration.
Transition Number Transition Next State
65 Edit Configuration Complete 5
Data Input Configuration Parameters N/A
Data Output None N/A
Control Input Configuration Parameters N/A
Status Output Configuration Verifications N/A
60 Power Switch to Off/Reboot 0
Data Input None N/A
Data Output None N/A
Control Input Disconnect Power Supply N/A
Status Output None / Display boot status on startup N/A
02 Conditional Test Failure 2
Data Input None N/A
Data Output None N/A
Control Input None N/A
Status Output Error logged N/A

State 7 - Bypass

The FSM is providing services without cryptographic processing (e.g., transferring plaintext calls through the FSM). In this state, the FSM is providing services with non-cryptographic processing (e.g., transferring plaintext through the module). The FSM can transition to a Bypass state when a call is received from an end point configured for non-encrypted calls.
Transition Number Transition Next State
74 POST Failure 4
Data Input None N/A
Data Output None N/A
Control Input Call is disconnected N/A
Status Output Call ends N/A
70 Power Switch to Off/Reboot 0
Data Input None N/A
Data Output None N/A
Control Input Disconnect Power Supply N/A
Status Output None / Display boot status on startup N/A