1. asymmetric cryptography
by David Kumar

2. Content What is a asymmetric Cryptosystem?
How Public Keys can be trusted
GnuPG
Creating Key pair
Handle the keys
Thunderbird
Questions?

3. Review: asymmetric cryptography
Public Key
Secret Key
Review

4. How Public Keys can be trusted
Authority Infrastructures
Public Key Infrastructure (PKI)
Financial transaction
Cross certification
Company's
Web of Trust
GnuPG
Review How Public Keys can be trusted

5. Public Key Infrastructure
Often used in combination with Hardware
Review How Public Keys can be trusted

6. Cross certification
Review How Public Keys can be trusted

7. Web of Trust allows anyone to sign anyone else's public key
Review How Public Keys can be trusted

8. GnuPG Under GNU General Public License Web of Trust Command line Tool
But there are some GUI’s for:
Instant messaging
Etc.
Review How Public Keys can be trusted  GnuPG

9. Creating Key pair gpg --gen-key (generates the sec. and pub. key)
Algorithm: DSA/ ElGamal
Key length
1024 – 4096 bits
duration of validity
Valid for ever
Valid for specific time:
days, weeks, month, years
Personal Information
Name, address
Passphrase
Review How Public Keys can be trusted  GnuPG

10. Creating Key pair Digital Signature Algorithm ElGamal (al-Dschamal)
Based on Diffie-Hellman:
Review How Public Keys can be trusted  GnuPG

11. Example GnuPG Key Review How Public Keys can be trusted  GnuPG
-----BEGIN PGP PUBLIC KEY BLOCK-----
Version: GnuPG v1.4.7 (MingW32)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=6ABD
-----END PGP PUBLIC KEY BLOCK-----
Review How Public Keys can be trusted  GnuPG

12. Key Export / Import Export: Import Show all keys:
gpg --export [UID] –o filename
Why export?
Import
gpg --import [Datei]
Why import?
Show all keys:
gpg --fingerprint
Review How Public Keys can be trusted  GnuPG

13. Signing a Key gpg --edit-key UID Be careful to sign Keys! sign
Review How Public Keys can be trusted  GnuPG

14. Thunderbird Enigmail Thunderbird Add-on: for GnuPG
Review How Public Keys can be trusted  GnuPG

15. Enigmail
Review How Public Keys can be trusted  GnuPG

16. Thunderbird
Review How Public Keys can be trusted  GnuPG

17. Thunderbird
Review How Public Keys can be trusted  GnuPG

18. Questions?
Review How Public Keys can be trusted  GnuPG THE END