Keys That Never Leave
A hardware security module is a tamper resistant device that generates and stores cryptographic keys and performs operations with them, so the private key never leaves the boundary. Applications send data to be signed or decrypted and receive only the result.
Why Use One
- Even a fully compromised host cannot extract the key material.
- Tamper resistance and physical hardening protect against extraction attempts.
- Built in access control and logging govern who can use each key.
Trade Offs
- Operations are bounded by the device's throughput, which can be a bottleneck.
- They add cost and operational complexity, so reserve them for high value keys.
- Cloud key management services offer hosted equivalents for many use cases.
Key idea
A hardware security module performs crypto so private keys never leave a tamper resistant boundary, protecting high value keys even on a compromised host.