plaintext input -> encryption algorithm -> decryption algorithm(reverse of encryption algorithm)-> plaintext output
y = E[K,X], X=D[K,Y]
Comparison of Encryption Algorithm
DES = Data Encryption Standard
AES = Advanced Encryption Standard
Plaintext block size(bits)
Ciphertext block size(bits)
Key size(bits)
Asymmetric Encryption
– plain text:readable message or data that is fed into the algorithm
– encryption algorithm: perform transformations on the plaintext
– public and private key: pair of keys, one for encryption, one for decryption
– ciphertext: scrambled message produced as output
– Decryption key: produces the original plaintext
Digital Signatures:
plaintext message -> hash function -> hashtag -> encrypted signed message -> compare the hash value sent with hash value generated -> reject message
Generate hash code of unsigned certificate -> Encrypt hash code with CA’s private key to form signature -> signed certificate -> decrypt signature with CA’s public key to recover hash code -> recepient can verify signature by comparison hash code values
