What is the NSA's Kremlin serial number 1 assumption?

The 'Kremlin serial number 1' assumption is an informal design maxim from the NSA's National Computer Security Center stating that engineers should assume the first unit of any new system falls immediately into adversary hands. This hardware security principle is a practical formulation of Kerckhoffs's principle and Shannon's maxim, which mandate that a cryptosystem must remain secure even when the enemy knows its exact operational details. Designing hardware under this premise ensures system security relies entirely on secret keys rather than hidden architecture.

What we know

• Former officials at the NSA's National Computer Security Center operated under the working assumption that serial number 1 of any new device was delivered directly to the Kremlin. [4]
• The Kremlin serial number 1 heuristic is a practical expression of Kerckhoffs's principle and Shannon's maxim, which state that a system must be designed assuming the enemy possesses full familiarity with it. [4]
• Computer security requires both physical security measures to protect hardware from physical tampering and digital safeguards like encryption. [2]
• Standardized cryptographic algorithms can be intentionally designed with covert backdoors, as occurred with the NSA-linked Dual EC DRBG random bit generator standard. [3]

Still open

• It is unclear whether the serial number 1 assumption was a formal written policy within the NSA or an informal rule of thumb shared among security engineers.

Where to go next

• the bigger pictureHow does Kerckhoffs's principle guide modern cryptography?
• how it workedHow was a backdoor hidden inside the Dual EC DRBG standard?
• how we knowWhy is physical tamper protection critical for secure hardware?
• compared withHow does Kerckhoffs's principle differ from security through obscurity?
• an unexpected connectionHow can mathematical elliptic curves be manipulated for surveillance?

Sources

• [1]computer security (Wikidata Q3510521) · CC0 1.0
• [2]Computer security · CC BY-SA 4.0
• [3]Dual EC DRBG · CC BY-SA 4.0
• [4]Kerckhoffs's principle · CC BY-SA 4.0
• [5]Elliptic-curve cryptography · CC BY-SA 4.0