Data Integrity
- Where did this information come from?
- Are you who you say you are?
- Is this the the original file?
- Are my files changed?
Issues:
- Digital data are easy to change
- Digital data are easy to compare to other
data (e.g., to see if a change happened)
- How do we know which version is correct?
- How do we know who you are?
Answers
- In a word, cryptography is the answer:
- Provides ways of digitally signing a document, and
verifying it
- Provides ways of transmitting it end-to-end to and
from a known source
- Provides ways of authenticating a particular
source of information
Things to know about
The real problem is that relatively little data
encryption and privacy protection is built into
standard software. You need to make an effort to use
it!
- Digital certificates for Web pages (e.g.,
https:// pages.
- Encryption offered by Web browsers (usually fairly
weak 40-bit encryption)
- How easy is it to decrypt an encrypted method
using the government standard DES? It's possible if you
really want to work at it!
- How does password encryption work with Unix? With NT?
- Can you use PGP or S/MIME to send encrypted email?
- Can you verify an email message using a digital signature?
- Emerging technologies include digital watermarks, to
verify graphics