# SEAS-8414 Chapter 11 Homework
## Blackboard Multiple-Choice Assessment: Formal Protocol Verification

**Use:** Due before the next Chapter 12 class session
**Total Points:** 100
**Format:** 50 single-correct-answer multiple choice questions, 2 points each
**Audience:** Doctoral students and senior cybersecurity practitioners

This assessment is designed for Blackboard delivery. Every item is multiple choice
with exactly one correct answer. The assessment is closed book: do not use the
textbook, notes, internet search, lab files, scanners, AI tools, or outside
incident writeups while answering.

Each question includes a scenario-provenance label. That label is a citation
trail for instructors and is never required to choose the answer. Every formula,
threshold, rule, or evidence contract required to answer appears inside the stem.

Chapter boundary: answer only within Chapter 11 formal protocol verification and model-limited security claims only. Do not import capabilities
from other chapters unless the stem explicitly defines them.

---

### Question 1

**Scenario provenance only (not needed to answer):** MITRE ATT&CK public knowledge base.

A university building-automation program estimates bounded-search growth. The rule is total_states = 1 + b + b^2 + ... + b^d. Branching factor b=3, depth d=4. Which total follows?

(a) 81
(b) 12
(c) 40
(d) 121
### Question 2

**Scenario provenance only (not needed to answer):** RFC 8446 TLS 1.3 standard.

A regional transit authority interprets a bounded protocol check. The rule is RED if a counterexample is found; YELLOW if no counterexample is found but the search bound is exhausted; GREEN if no counterexample is found and the search completes without exhausting the bound. counterexample_found=False, bound_exhausted=False. Which verdict follows?

(a) RED
(b) PASS_UNCONDITIONALLY
(c) GREEN
(d) YELLOW
### Question 3

**Scenario provenance only (not needed to answer):** CISA AA21-042A on the 2021 U.S. water treatment facility compromise.

A water utility runs a TLS downgrade screen. The rule flags one issue for each true condition: SSLv3_enabled, export_cipher_enabled, RSA_key_exchange_enabled, TLS_compression_enabled. Observed: SSLv3=False, export_cipher=True, RSA_key_exchange=True, compression=False. How many downgrade issues are flagged?

(a) 4
(b) 2
(c) No determinate answer can be computed from the stated rule.
(d) 1
### Question 4

**Scenario provenance only (not needed to answer):** NIST SP 800-82 Rev. 3 guidance for operational technology.

A hospital medical-device network checks an authentication correspondence property. The rule is: every server_accept event for a nonce must have a preceding client_start event for that nonce. The trace has 7 matching client_start events and 7 server_accept events for distinct nonces. Extra accepts are violations. How many violations follow?

(a) 0
(b) No determinate answer can be computed from the stated rule.
(c) 7
(d) Escalate automatically without applying the numeric rule.
### Question 5

**Scenario provenance only (not needed to answer):** MITRE ATT&CK for ICS public knowledge base.

A maritime port authority verifies replay protection. The rule is: accept the first occurrence of a nonce and reject every duplicate nonce. The trace contains 17 messages and 0 duplicate nonce occurrences. How many messages are accepted?

(a) 0
(b) No determinate answer can be computed from the stated rule.
(c) Escalate automatically without applying the numeric rule.
(d) 17
### Question 6

**Scenario provenance only (not needed to answer):** Mirai botnet public research by Antonakakis et al..

A smart-building operator evaluates forward secrecy under a simplified Chapter 11 rule. A session has forward secrecy against later long-term-key compromise if the session key is derived from ephemeral DH rather than static RSA transport. ephemeral_DH=False, static_RSA_transport=True, later_long_term_key_compromise=True. Which result follows?

(a) formal proof is impossible because TLS cannot be modeled
(b) result is unrelated to key exchange
(c) forward secrecy fails under this rule
(d) forward secrecy holds under this rule
### Question 7

**Scenario provenance only (not needed to answer):** IEC 62443 industrial automation security standard.

A rail signaling operator checks a bounded response property. The rule is: every request must be followed by a response within 3 trace steps. The trace has 7 requests; 3 of them receive a response after more than 3 steps. How many property violations follow?

(a) 0
(b) 3
(c) 4
(d) 7
### Question 8

**Scenario provenance only (not needed to answer):** NIST Cybersecurity Framework 2.0.

A food processing plant tests a known counterexample in a bounded checker. The counterexample requires depth 47. The configured max_depth is 40. The checker finds the counterexample only when max_depth >= required depth. Which result follows?

(a) counterexample not reachable at this bound
(b) counterexample reachable
(c) proof of safety
(d) model invalid because depth is numeric
### Question 9

**Scenario provenance only (not needed to answer):** CISA Known Exploited Vulnerabilities Catalog.

An airport baggage-handling network verifies cross-layer identity binding. The rule is: MQTT identity is bound to TLS identity only when mqtt_username equals certificate_subject. certificate_subject=device-4; mqtt_username=device-0. Which result follows?

(a) identity binding holds
(b) TLS secrecy implies MQTT identity binding automatically
(c) MQTT identity is out of Chapter 11 scope
(d) identity binding fails
### Question 10

**Scenario provenance only (not needed to answer):** Cui and Stolfo embedded device insecurity research.

A municipal camera program reviews a Dolev-Yao deduction. The self-contained rule is: an attacker can derive secret m from enc(m, pk_server) only if the attacker has both the ciphertext enc(m, pk_server) and the matching private key sk_server. Observed attacker knowledge: ciphertext=True, sk_server=True. Which derivation result follows?

(a) proof is GREEN because ciphertext exists
(b) model is out of scope because Dolev-Yao cannot represent encryption
(c) attacker can derive m
(d) attacker cannot derive m under this rule
### Question 11

**Scenario provenance only (not needed to answer):** NIST SP 800-82 Rev. 3 guidance for operational technology.

An electric cooperative estimates bounded-search growth. The rule is total_states = 1 + b + b^2 + ... + b^d. Branching factor b=5, depth d=5. Which total follows?

(a) 781
(b) 3906
(c) 3125
(d) 25
### Question 12

**Scenario provenance only (not needed to answer):** IEC 62443 industrial automation security standard.

A chemical manufacturing site interprets a bounded protocol check. The rule is RED if a counterexample is found; YELLOW if no counterexample is found but the search bound is exhausted; GREEN if no counterexample is found and the search completes without exhausting the bound. counterexample_found=True, bound_exhausted=True. Which verdict follows?

(a) RED
(b) GREEN
(c) No determinate answer can be computed from the stated rule.
(d) PASS_UNCONDITIONALLY
### Question 13

**Scenario provenance only (not needed to answer):** MITRE ATT&CK public knowledge base.

A university building-automation program runs a TLS downgrade screen. The rule flags one issue for each true condition: SSLv3_enabled, export_cipher_enabled, RSA_key_exchange_enabled, TLS_compression_enabled. Observed: SSLv3=False, export_cipher=False, RSA_key_exchange=True, compression=False. How many downgrade issues are flagged?

(a) 3
(b) No determinate answer can be computed from the stated rule.
(c) 4
(d) 1
### Question 14

**Scenario provenance only (not needed to answer):** RFC 8446 TLS 1.3 standard.

A regional transit authority checks an authentication correspondence property. The rule is: every server_accept event for a nonce must have a preceding client_start event for that nonce. The trace has 7 matching client_start events and 8 server_accept events for distinct nonces. Extra accepts are violations. How many violations follow?

(a) 8
(b) No determinate answer can be computed from the stated rule.
(c) 1
(d) 0
### Question 15

**Scenario provenance only (not needed to answer):** CISA AA21-042A on the 2021 U.S. water treatment facility compromise.

A water utility verifies replay protection. The rule is: accept the first occurrence of a nonce and reject every duplicate nonce. The trace contains 19 messages and 0 duplicate nonce occurrences. How many messages are accepted?

(a) Escalate automatically without applying the numeric rule.
(b) 19
(c) 0
(d) No determinate answer can be computed from the stated rule.
### Question 16

**Scenario provenance only (not needed to answer):** NIST SP 800-82 Rev. 3 guidance for operational technology.

A hospital medical-device network evaluates forward secrecy under a simplified Chapter 11 rule. A session has forward secrecy against later long-term-key compromise if the session key is derived from ephemeral DH rather than static RSA transport. ephemeral_DH=True, static_RSA_transport=False, later_long_term_key_compromise=True. Which result follows?

(a) forward secrecy holds under this rule
(b) forward secrecy fails under this rule
(c) formal proof is impossible because TLS cannot be modeled
(d) result is unrelated to key exchange
### Question 17

**Scenario provenance only (not needed to answer):** MITRE ATT&CK for ICS public knowledge base.

A maritime port authority checks a bounded response property. The rule is: every request must be followed by a response within 3 trace steps. The trace has 7 requests; 1 of them receive a response after more than 3 steps. How many property violations follow?

(a) 6
(b) 7
(c) 0
(d) 1
### Question 18

**Scenario provenance only (not needed to answer):** Mirai botnet public research by Antonakakis et al..

A smart-building operator tests a known counterexample in a bounded checker. The counterexample requires depth 62. The configured max_depth is 52. The checker finds the counterexample only when max_depth >= required depth. Which result follows?

(a) proof of safety
(b) model invalid because depth is numeric
(c) counterexample not reachable at this bound
(d) counterexample reachable
### Question 19

**Scenario provenance only (not needed to answer):** IEC 62443 industrial automation security standard.

A rail signaling operator verifies cross-layer identity binding. The rule is: MQTT identity is bound to TLS identity only when mqtt_username equals certificate_subject. certificate_subject=device-4; mqtt_username=device-4. Which result follows?

(a) MQTT identity is out of Chapter 11 scope
(b) identity binding holds
(c) identity binding fails
(d) TLS secrecy implies MQTT identity binding automatically
### Question 20

**Scenario provenance only (not needed to answer):** NIST Cybersecurity Framework 2.0.

A food processing plant reviews a Dolev-Yao deduction. The self-contained rule is: an attacker can derive secret m from enc(m, pk_server) only if the attacker has both the ciphertext enc(m, pk_server) and the matching private key sk_server. Observed attacker knowledge: ciphertext=True, sk_server=True. Which derivation result follows?

(a) attacker can derive m
(b) attacker cannot derive m under this rule
(c) proof is GREEN because ciphertext exists
(d) model is out of scope because Dolev-Yao cannot represent encryption
### Question 21

**Scenario provenance only (not needed to answer):** CISA Known Exploited Vulnerabilities Catalog.

An airport baggage-handling network estimates bounded-search growth. The rule is total_states = 1 + b + b^2 + ... + b^d. Branching factor b=3, depth d=3. Which total follows?

(a) 27
(b) 9
(c) 13
(d) 40
### Question 22

**Scenario provenance only (not needed to answer):** Cui and Stolfo embedded device insecurity research.

A municipal camera program interprets a bounded protocol check. The rule is RED if a counterexample is found; YELLOW if no counterexample is found but the search bound is exhausted; GREEN if no counterexample is found and the search completes without exhausting the bound. counterexample_found=False, bound_exhausted=False. Which verdict follows?

(a) RED
(b) PASS_UNCONDITIONALLY
(c) GREEN
(d) YELLOW
### Question 23

**Scenario provenance only (not needed to answer):** NIST SP 800-82 Rev. 3 guidance for operational technology.

An electric cooperative runs a TLS downgrade screen. The rule flags one issue for each true condition: SSLv3_enabled, export_cipher_enabled, RSA_key_exchange_enabled, TLS_compression_enabled. Observed: SSLv3=False, export_cipher=False, RSA_key_exchange=True, compression=False. How many downgrade issues are flagged?

(a) 4
(b) 1
(c) 3
(d) No determinate answer can be computed from the stated rule.
### Question 24

**Scenario provenance only (not needed to answer):** IEC 62443 industrial automation security standard.

A chemical manufacturing site checks an authentication correspondence property. The rule is: every server_accept event for a nonce must have a preceding client_start event for that nonce. The trace has 7 matching client_start events and 6 server_accept events for distinct nonces. Extra accepts are violations. How many violations follow?

(a) 0
(b) 1
(c) 6
(d) No determinate answer can be computed from the stated rule.
### Question 25

**Scenario provenance only (not needed to answer):** MITRE ATT&CK public knowledge base.

A university building-automation program verifies replay protection. The rule is: accept the first occurrence of a nonce and reject every duplicate nonce. The trace contains 13 messages and 0 duplicate nonce occurrences. How many messages are accepted?

(a) 0
(b) No determinate answer can be computed from the stated rule.
(c) Escalate automatically without applying the numeric rule.
(d) 13
### Question 26

**Scenario provenance only (not needed to answer):** RFC 8446 TLS 1.3 standard.

A regional transit authority evaluates forward secrecy under a simplified Chapter 11 rule. A session has forward secrecy against later long-term-key compromise if the session key is derived from ephemeral DH rather than static RSA transport. ephemeral_DH=True, static_RSA_transport=False, later_long_term_key_compromise=True. Which result follows?

(a) formal proof is impossible because TLS cannot be modeled
(b) result is unrelated to key exchange
(c) forward secrecy holds under this rule
(d) forward secrecy fails under this rule
### Question 27

**Scenario provenance only (not needed to answer):** CISA AA21-042A on the 2021 U.S. water treatment facility compromise.

A water utility checks a bounded response property. The rule is: every request must be followed by a response within 3 trace steps. The trace has 7 requests; 3 of them receive a response after more than 3 steps. How many property violations follow?

(a) 0
(b) 3
(c) 4
(d) 7
### Question 28

**Scenario provenance only (not needed to answer):** NIST SP 800-82 Rev. 3 guidance for operational technology.

A hospital medical-device network tests a known counterexample in a bounded checker. The counterexample requires depth 42. The configured max_depth is 64. The checker finds the counterexample only when max_depth >= required depth. Which result follows?

(a) counterexample reachable
(b) counterexample not reachable at this bound
(c) proof of safety
(d) model invalid because depth is numeric
### Question 29

**Scenario provenance only (not needed to answer):** MITRE ATT&CK for ICS public knowledge base.

A maritime port authority verifies cross-layer identity binding. The rule is: MQTT identity is bound to TLS identity only when mqtt_username equals certificate_subject. certificate_subject=device-4; mqtt_username=device-4. Which result follows?

(a) identity binding fails
(b) TLS secrecy implies MQTT identity binding automatically
(c) MQTT identity is out of Chapter 11 scope
(d) identity binding holds
### Question 30

**Scenario provenance only (not needed to answer):** Mirai botnet public research by Antonakakis et al..

A smart-building operator reviews a Dolev-Yao deduction. The self-contained rule is: an attacker can derive secret m from enc(m, pk_server) only if the attacker has both the ciphertext enc(m, pk_server) and the matching private key sk_server. Observed attacker knowledge: ciphertext=True, sk_server=False. Which derivation result follows?

(a) proof is GREEN because ciphertext exists
(b) model is out of scope because Dolev-Yao cannot represent encryption
(c) attacker cannot derive m under this rule
(d) attacker can derive m
### Question 31

**Scenario provenance only (not needed to answer):** IEC 62443 industrial automation security standard.

A rail signaling operator estimates bounded-search growth. The rule is total_states = 1 + b + b^2 + ... + b^d. Branching factor b=5, depth d=4. Which total follows?

(a) 156
(b) 781
(c) 625
(d) 20
### Question 32

**Scenario provenance only (not needed to answer):** NIST Cybersecurity Framework 2.0.

A food processing plant interprets a bounded protocol check. The rule is RED if a counterexample is found; YELLOW if no counterexample is found but the search bound is exhausted; GREEN if no counterexample is found and the search completes without exhausting the bound. counterexample_found=False, bound_exhausted=True. Which verdict follows?

(a) YELLOW
(b) GREEN
(c) RED
(d) PASS_UNCONDITIONALLY
### Question 33

**Scenario provenance only (not needed to answer):** CISA Known Exploited Vulnerabilities Catalog.

An airport baggage-handling network runs a TLS downgrade screen. The rule flags one issue for each true condition: SSLv3_enabled, export_cipher_enabled, RSA_key_exchange_enabled, TLS_compression_enabled. Observed: SSLv3=False, export_cipher=True, RSA_key_exchange=True, compression=False. How many downgrade issues are flagged?

(a) No determinate answer can be computed from the stated rule.
(b) 1
(c) 4
(d) 2
### Question 34

**Scenario provenance only (not needed to answer):** Cui and Stolfo embedded device insecurity research.

A municipal camera program checks an authentication correspondence property. The rule is: every server_accept event for a nonce must have a preceding client_start event for that nonce. The trace has 7 matching client_start events and 7 server_accept events for distinct nonces. Extra accepts are violations. How many violations follow?

(a) 7
(b) Escalate automatically without applying the numeric rule.
(c) 0
(d) No determinate answer can be computed from the stated rule.
### Question 35

**Scenario provenance only (not needed to answer):** NIST SP 800-82 Rev. 3 guidance for operational technology.

An electric cooperative verifies replay protection. The rule is: accept the first occurrence of a nonce and reject every duplicate nonce. The trace contains 15 messages and 0 duplicate nonce occurrences. How many messages are accepted?

(a) Escalate automatically without applying the numeric rule.
(b) 15
(c) 0
(d) No determinate answer can be computed from the stated rule.
### Question 36

**Scenario provenance only (not needed to answer):** IEC 62443 industrial automation security standard.

A chemical manufacturing site evaluates forward secrecy under a simplified Chapter 11 rule. A session has forward secrecy against later long-term-key compromise if the session key is derived from ephemeral DH rather than static RSA transport. ephemeral_DH=False, static_RSA_transport=True, later_long_term_key_compromise=True. Which result follows?

(a) forward secrecy fails under this rule
(b) forward secrecy holds under this rule
(c) formal proof is impossible because TLS cannot be modeled
(d) result is unrelated to key exchange
### Question 37

**Scenario provenance only (not needed to answer):** MITRE ATT&CK public knowledge base.

A university building-automation program checks a bounded response property. The rule is: every request must be followed by a response within 3 trace steps. The trace has 7 requests; 1 of them receive a response after more than 3 steps. How many property violations follow?

(a) 6
(b) 7
(c) 0
(d) 1
### Question 38

**Scenario provenance only (not needed to answer):** RFC 8446 TLS 1.3 standard.

A regional transit authority tests a known counterexample in a bounded checker. The counterexample requires depth 57. The configured max_depth is 76. The checker finds the counterexample only when max_depth >= required depth. Which result follows?

(a) proof of safety
(b) model invalid because depth is numeric
(c) counterexample reachable
(d) counterexample not reachable at this bound
### Question 39

**Scenario provenance only (not needed to answer):** CISA AA21-042A on the 2021 U.S. water treatment facility compromise.

A water utility verifies cross-layer identity binding. The rule is: MQTT identity is bound to TLS identity only when mqtt_username equals certificate_subject. certificate_subject=device-4; mqtt_username=device-0. Which result follows?

(a) MQTT identity is out of Chapter 11 scope
(b) identity binding fails
(c) identity binding holds
(d) TLS secrecy implies MQTT identity binding automatically
### Question 40

**Scenario provenance only (not needed to answer):** NIST SP 800-82 Rev. 3 guidance for operational technology.

A hospital medical-device network reviews a Dolev-Yao deduction. The self-contained rule is: an attacker can derive secret m from enc(m, pk_server) only if the attacker has both the ciphertext enc(m, pk_server) and the matching private key sk_server. Observed attacker knowledge: ciphertext=True, sk_server=True. Which derivation result follows?

(a) attacker can derive m
(b) attacker cannot derive m under this rule
(c) proof is GREEN because ciphertext exists
(d) model is out of scope because Dolev-Yao cannot represent encryption
### Question 41

**Scenario provenance only (not needed to answer):** MITRE ATT&CK for ICS public knowledge base.

A maritime port authority estimates bounded-search growth. The rule is total_states = 1 + b + b^2 + ... + b^d. Branching factor b=3, depth d=5. Which total follows?

(a) 243
(b) 15
(c) 121
(d) 364
### Question 42

**Scenario provenance only (not needed to answer):** Mirai botnet public research by Antonakakis et al..

A smart-building operator interprets a bounded protocol check. The rule is RED if a counterexample is found; YELLOW if no counterexample is found but the search bound is exhausted; GREEN if no counterexample is found and the search completes without exhausting the bound. counterexample_found=True, bound_exhausted=False. Which verdict follows?

(a) No determinate answer can be computed from the stated rule.
(b) PASS_UNCONDITIONALLY
(c) RED
(d) GREEN
### Question 43

**Scenario provenance only (not needed to answer):** IEC 62443 industrial automation security standard.

A rail signaling operator runs a TLS downgrade screen. The rule flags one issue for each true condition: SSLv3_enabled, export_cipher_enabled, RSA_key_exchange_enabled, TLS_compression_enabled. Observed: SSLv3=False, export_cipher=False, RSA_key_exchange=True, compression=False. How many downgrade issues are flagged?

(a) 4
(b) 1
(c) 3
(d) No determinate answer can be computed from the stated rule.
### Question 44

**Scenario provenance only (not needed to answer):** NIST Cybersecurity Framework 2.0.

A food processing plant checks an authentication correspondence property. The rule is: every server_accept event for a nonce must have a preceding client_start event for that nonce. The trace has 7 matching client_start events and 8 server_accept events for distinct nonces. Extra accepts are violations. How many violations follow?

(a) 1
(b) 0
(c) 8
(d) No determinate answer can be computed from the stated rule.
### Question 45

**Scenario provenance only (not needed to answer):** CISA Known Exploited Vulnerabilities Catalog.

An airport baggage-handling network verifies replay protection. The rule is: accept the first occurrence of a nonce and reject every duplicate nonce. The trace contains 17 messages and 0 duplicate nonce occurrences. How many messages are accepted?

(a) 0
(b) No determinate answer can be computed from the stated rule.
(c) Escalate automatically without applying the numeric rule.
(d) 17
### Question 46

**Scenario provenance only (not needed to answer):** Cui and Stolfo embedded device insecurity research.

A municipal camera program evaluates forward secrecy under a simplified Chapter 11 rule. A session has forward secrecy against later long-term-key compromise if the session key is derived from ephemeral DH rather than static RSA transport. ephemeral_DH=True, static_RSA_transport=False, later_long_term_key_compromise=True. Which result follows?

(a) formal proof is impossible because TLS cannot be modeled
(b) result is unrelated to key exchange
(c) forward secrecy holds under this rule
(d) forward secrecy fails under this rule
### Question 47

**Scenario provenance only (not needed to answer):** NIST SP 800-82 Rev. 3 guidance for operational technology.

An electric cooperative checks a bounded response property. The rule is: every request must be followed by a response within 3 trace steps. The trace has 7 requests; 3 of them receive a response after more than 3 steps. How many property violations follow?

(a) 0
(b) 3
(c) 4
(d) 7
### Question 48

**Scenario provenance only (not needed to answer):** IEC 62443 industrial automation security standard.

A chemical manufacturing site tests a known counterexample in a bounded checker. The counterexample requires depth 72. The configured max_depth is 40. The checker finds the counterexample only when max_depth >= required depth. Which result follows?

(a) counterexample not reachable at this bound
(b) counterexample reachable
(c) proof of safety
(d) model invalid because depth is numeric
### Question 49

**Scenario provenance only (not needed to answer):** MITRE ATT&CK public knowledge base.

A university building-automation program verifies cross-layer identity binding. The rule is: MQTT identity is bound to TLS identity only when mqtt_username equals certificate_subject. certificate_subject=device-4; mqtt_username=device-4. Which result follows?

(a) identity binding fails
(b) TLS secrecy implies MQTT identity binding automatically
(c) MQTT identity is out of Chapter 11 scope
(d) identity binding holds
### Question 50

**Scenario provenance only (not needed to answer):** RFC 8446 TLS 1.3 standard.

A regional transit authority reviews a Dolev-Yao deduction. The self-contained rule is: an attacker can derive secret m from enc(m, pk_server) only if the attacker has both the ciphertext enc(m, pk_server) and the matching private key sk_server. Observed attacker knowledge: ciphertext=True, sk_server=True. Which derivation result follows?

(a) proof is GREEN because ciphertext exists
(b) model is out of scope because Dolev-Yao cannot represent encryption
(c) attacker can derive m
(d) attacker cannot derive m under this rule
