Likely to be predictable True random number generator (TRNG): • Uses a nondeterministic source to produce randomness • Most operate by measuring unpredictable natural processes • e.g. radiation, gas discharge, leaky capacitors • Increasingly provided on modern processors 31
Practical Application: Encryption of Stored Data Common to encrypt transmitted data Much less common for stored data There is often little protection beyond domain authentication and operating system access controls Data are archived for indefinite periods Even though erased, until disk sectors are reused data are recoverable Approaches to encrypt stored data: Use a commercially available encryption package Back-end appliance Library based tape encryption Background laptop/PC data encryption 32
Summary • Public-key encryption Structure Applications for public- key cryptosystems Requirements for public- key cryptography Asymmetric encryption algorithms • Digital signatures and key management Digital signature Public-key certificates Symmetric key exchange using public-key encryption Digital envelopes • Confidentiality with symmetric encryption Symmetric encryption Symmetric block encryption algorithms Stream ciphers • Message authentication and hash functions Authentication using symmetric encryption Message authentication without message encryption Secure hash functions Other applications of hash functions • Random and pseudorandom numbers The use of random numbers Random versus pseudorandom 33
You've reached the end of your free preview.
Want to read all 33 pages?
- Spring '19