The document introduces cryptography concepts like encryption, decryption, symmetric and public key cryptography. It discusses why cryptography is important for secure communication between parties like Alice and Bob, and the challenges of implementing it in JavaScript due to issues like entropy and performance. The document serves as an introduction to cryptography topics for a meetup of JavaScript friends.

1. cryptography in
javascript
what the hell?!
!
brnojs
a.k.a.
stretnutie kamarátov javascriptu

2. introduction Cryptography
What?

3. introduction Communication
Alice
Bob
Eve

4. introduction Secure?
Integrity

5. introduction Secure?
Confidentiality

6. introduction Cryptography
Why?

7. introduction Encryption and decryption
ciphertext := Encrypt(key, message)
!
message := Decrypt(key, ciphertext)

8. introduction Symmetric-key crypto
C := E(K, M)
M := D(K, C)

9. introduction Public-key crypto
C := E(Kpublic, M)
M := D(Kprivate, C)

10. problems Why is it hard?
Entropy

11. problems Why is it hard?
Performance

12. conclusion Konec
Want to know more?

13. thank you
for your attention
Martin Kačmar
@martinkacmar