- LPU MCA Semester 1
- CAP470
- Unit 6
CAP470 · Unit 6: Cloud security and standards
Data security, data integrity, encryption and key management
13 practice questions · in the ETE syllabus
Key points
- CIA: confidentiality, integrity, availability
- Symmetric uses one key; asymmetric uses a key pair
- Hashes detect tampering; Base64 is not encryption
- Protect data at rest and in transit; manage keys carefully
Information security aims for the CIA triad: confidentiality (only authorised people can read data), integrity (data is not altered without authorisation) and availability (data can be reached when needed).
| Tool | Idea |
|---|---|
| Symmetric encryption (AES) | One shared key encrypts and decrypts; fast |
| Asymmetric encryption (RSA) | Public key encrypts, private key decrypts |
| Digital signature | Private key signs, public key verifies |
| Hash (SHA-256) | One-way digest used to detect changes |
| TLS | Encrypts data in transit (HTTPS) |
A hash gives completely different digests for slightly different inputs (cloud and Cloud), so comparing digests detects tampering. Applying a XOR cipher with the same key twice restores the original, which is the symmetric idea. Base64 is only an encoding that anyone can reverse without a key, so it is not encryption.
Data is protected at rest (stored) with disk or object encryption and in transit (moving) with TLS. Key management means generating, storing, rotating and restricting access to keys, often with a managed key service, because encryption is only as strong as the protection of its keys.
Exam trap: a hash cannot be decrypted, and Base64 is not secret. Neither replaces encryption.
Try two questions
What is the main purpose of key management in cloud encryption?
- To make encryption keys as short as possible to save space
- To publish every private key so that auditors can read it
- To remove the need for encryption in the cloud entirely
- To generate, store, rotate and control access to encryption keys safely
Show the answer
D. Strong encryption is only as safe as the way its keys are handled.
Why not A: Short keys weaken security.
Why not B: Private keys must stay secret.
Why not C: Key management supports encryption, it does not replace it.
Which type of encryption uses the same key to encrypt and decrypt data?
- Asymmetric encryption
- Symmetric encryption
- Hash functions
- Digital certificates
Show the answer
B. Symmetric algorithms such as AES are fast and use one shared secret key.
Why not A: Asymmetric encryption uses a public and a private key.
Why not C: Hash functions are one-way and have no decryption.
Why not D: Certificates bind a public key to an identity.