Public KeyCryptosystems
Symmetric Cryptosystems20/04/23 | pag. 2
Why?
Cryptography 20/04/23 | pag. 3
Why?
Cryptography 20/04/23 | pag. 4
Public Key Cryptosystems
Cryptography 20/04/23 | pag. 5
before.
Public Key Cryptosystems
Cryptography 20/04/23 | pag. 6
addressed by identification.
Public Key Cryptosystems
Cryptography 20/04/23 | pag. 7
Public Key Cryptosystems
• RSA Cryptosystem
• Rabin Encryption
• ElGamal Encryption(based on Diffie-Hellman Key Exchange)
Cryptography 20/04/23 | pag. 8
RSA
Cryptography 20/04/23 | pag. 9
RSA:Key generation
Cryptography 20/04/23 | pag. 10
RSA:Key generation
Cryptography 20/04/23 | pag. 11
RSA:Encryption
Cryptography 20/04/23 | pag. 12
RSA:Encryption – Block cipher
Cryptography 20/04/23 | pag. 13
RSA:Encryption – Block cipher
Cryptography 20/04/23 | pag. 14
RSA:Decryption
Cryptography 20/04/23 | pag. 15
We need a little of Fermat!
Intermezzo:Fermat’s Little Theorem
Cryptography 20/04/23 | pag. 16
Intermezzo:Fermat’s Little Theorem
Cryptography 20/04/23 | pag. 17
RSA:Decryption
Cryptography 20/04/23 | pag. 18
RSA:Decryption
Cryptography 20/04/23 | pag. 19
Example:RSA
Cryptography 20/04/23 | pag. 20
119147119
Security of the RSA
Cryptography 20/04/23 | pag. 21
Rabin Encryption
Cryptography 20/04/23 | pag. 22
Rabin Encryption:Key generation
Cryptography 20/04/23 | pag. 23
Rabin Encryption:Encryption
Cryptography 20/04/23 | pag. 24
Rabin Encryption:Decryption
Cryptography 20/04/23 | pag. 25
Rabin Encryption:Decryption
Cryptography 20/04/23 | pag. 26