M-209 cipher machine.

Cloud Data Security Domain

Intellectual Property

Data Rights Management / Information Rights Management

Data Storage Models

Database encryption

Data Masking — hide, replace, or omit sensitive data



Data Anonymization

Similar to masking, also remove indirect identifiers to prevent analysis figuring out what PII would have directly shown.

Used to analyze statistics on large collection containing PII.

Data Tokenization

Replace a sensitive data element with a token, a random value with shape and form of original. A tokenization application maps between the tokens and actual values. Needs a second database.

PCI DSS requires either encryption or tokenization of PII and card data.

Bit Splitting

Encrypt, split ciphertext and key across storage locations. With redundancy, your data survives individual drive failures, or seizures of some media by law enforcement.

Generate a random 256-bit key, encrypt your data with AES-CBC. For each 8-bit block of the ciphertext and the key, store:

You could reassemble the ciphertext and key with the data from any two clouds. That's all you need to understand for the test.

In the real world, each data center and its corporate headquarters would have to be in a separate country. And in the really real world with the US CLOUD Act, no more than one could be in the U.S. or another Five Eyes country, or any other country where the U.S. has strong influence. Chile, South Africa, India, and Singapore might work, as long as the cloud providers have their headquarters in those countries.

More advanced, possible but less likely to appear:

Quantum Science

Quantum computing is offensive, a threat to break ciphers and expose secrets. A truly general-purpose quantum computer with enough stable qubits could run Shor's algorithm to quickly solve the now "too difficult" problems that protect asymmetric ciphers — factoring for RSA and discrete logarithm for ECC. Symmetric ciphers should (as far as we currently understand) be relatively safe, Grover's algorithm reduces a 256-bit cipher to the resistance of a 128-bit cipher against brute-force search.

Quantum cryptography is defensive, to protect secrets. It's really about QKD or Quantum Key Distribution, using single-photon signaling to transmit a key to be used in a conventional symmetric cipher. China is a world leader in this, see one of my "Just Enough Cryptography" pages for details on the Chinese quantum Internet.

Responsibility depending on type of cloud service

IaaS PaaS SaaS
Security GRC
(Governance, Risk, and Compliance)
Enterprise Enterprise Enterprise
Data Security Enterprise Enterprise Enterprise
Application Security Enterprise Enterprise Shared
Platform Security Enterprise Shared CSP
Infrastructure Security Shared CSP CSP
Physical Security CSP CSP CSP

Shared because:

Now That You Know Cryptography...

There are some questions where knowing all the technology doesn't give you the correct answer. You must carefully analyze the English prose.

(ISC)2 isn't as bad as CompTIA about doing this, but they still do it on some questions.

Here's are two examples, from my CompTIA Security+ study suggestion page. In the second one, "BPA" means "Business Partnership Agreement". You can click "See the answer" to be taken to the answer and its explanation, and then "Return to main page" to get back here:

Example Question #1

Question: You want to use a system that can protect communication by authenticating the server, and also providing a copy of the server's public key in a trustworthy format. A provider of trusted certificates will only provide one when you follow their rules. There is a protocol that you can use to check in real time whether a certificate should be trusted or not. You must have a copy of the currently untrusted certificates locally, to reduce network traffic. Rather than a complete copy of the key, you may refer to its hash instead. There are ways to prevent a breach today from exposing secrets based on keys in the past. What do you need?

E: thumbprint

See the answer

Example Question #2

Question: Your CEO has met with the CEO of another company, and they have agreed to work together to develop a new service. Authentication and identity management will be connected across the two organizations. Given the sensitivity of the development project, User authentication and authorization will use a centralized server running the best available trusted third-party service. Users will receive identity and service tokens from a unified authentication and authorization service, which requires that system clocks be synchronized across the organizations. Applications will be limited to those written with the API of that service. What do you need?

B: Federation
C: Kerberos
F: Kerberization

See the answer