Storage Trade-offs

Understanding the trade-offs in encrypted storage.

Encryption overhead

Storage size

• ~1-5% overhead for encryption metadata
• ~10-20% for searchable encryption indexes

Latency

• Encryption: ~1ms per MB
• Decryption: ~1ms per MB
• Key operations: ~5ms

Searchable encryption trade-offs

Functionality vs security

Feature	Plaintext	SSE
Full-text search	✓	Limited
Regex	✓	✗
Fuzzy match	✓	Limited
Aggregations	✓	Limited
Joins	✓	✗

Security vs performance

Security level	Query latency	Index size
Basic SSE	2x	1.1x
Forward-secure	3x	1.2x
Fully oblivious	10x	2x

Client-side vs server-side encryption

Aspect	CSE	SSE
Key custody	Client	Server
Performance	Client CPU	Server CPU
Complexity	Higher	Lower
Zero-knowledge	Yes	No

Recommendations

Use CSE when

• Maximum security required
• Regulatory key custody requirements
• Zero-trust model

Use SSE when

• Simpler integration needed
• Server-side processing required
• Performance critical

Use searchable encryption when

• Need to query encrypted data
• Can accept functionality limits
• Privacy outweighs convenience