This presentation tries to deliver a baseline understanding of how encryption works and impacts our communications. It discusses public and private keypairs, symmetric & assymetric encryptions - all of which are common concepts under AES, RSA, SSH standards

1. Encryptions
Symmetric vs Asymmetric
by Syed Rakib Al Hasan

3. Hello
Friend
Hello
Friend
Passing plain text message
Hello
Friend

4. Encryption
- using a key to
scramble a message
97987
91368
71378
Hello
Friend

5. 97987
91368
71378
97987
91368
71378
Passing encrypted message
Hello
Friend
97987
91368
71378

6. Pass the encryption
key to the recipient
first, so that they can
decrypt your
encrypted messages
when they receive it

7. Passing the encryption key

8. 97987
91368
71378
97987
91368
71378
Hello
Friend
97987
91368
71378
Hello
Friend
Hello
Friend
When everyone has the encryption key

9. Symmetric Encryption
- same key to encrypt
& decrypt a message

10. AES Encryption
is a kind of
symmetric encryption

11. How to solve this
lock & key problem?

12. Welcome asymmetric
encryption

13. Public key Private key
- The encryptor - The decryptor

14. Hello
Friend
97987
91368
71378
97987
91368
71378
!@^%!
*&*#(_
)@!!@
97987
91368
71378
Hello
Friend

15. Ask for the recipient’s
public key first, so that
you can encrypt your
messages with their
public key before you
send it to them.

16. Asymmetric encryption - requesting public key of the recipient
GIve me your public key Okay
¯_(ツ)_/¯

17. Asymmetric encryption - sharing public key with the sender

18. 97987
91368
71378
97987
91368
71378
Asymmetric encryption - sender encrypts and passes the encrypted message
Hello
Friend
97987
91368
71378

19. 97987
91368
71378
97987
91368
71378
Asymmetric encryption - decrypting the encrypted message
Hello
Friend
97987
91368
71378
Hello
Friend
!@^%!
*&*#(_
)@!!@

20. RSA Encryption
is a kind of
asymmetric encryption

21. We use RSA standard
when we authenticate
with SSH keypairs

22. Symmetric
Encryption
Key is passed from message sender
to message receiver
A single key is involved
Same key is used for
encryption + decryption
Asymmetric
Encryption
Key is passed from message receiver
to message sender
A keyPAIR is involved
Separate key is maintained privately by
the receiver to decrypt messages

23. Public Key Private Key
It’s okay to expose and reveal to the world Must remain a secret at ALL times
It’s okay to create duplicates/copies Must never produce duplicates

25. That’s all