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:

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