10-01-2012, 03:14 PM
Cryptography simple report
46612381-Ppt-on-Cryptography-5.ppt (Size: 2.17 MB / Downloads: 365)
What is Cryptography?
This is the art of
keeping messages
secret
Secret Key Cryptography-
Follows SYMMETRIC
ALGORITHMS.
Single key used to
encrypt and decrypt.
Key must be known
by both parties.
Public Key Cryptography-
Follows ASYMMETRIC
ALGORITHMS.
Each entity has 2 keys:
private key (a secret)
public key (well known)
Using Keys
Private keys are used for
decrypting.
Public keys are used for
encrypting.
encryption
plaintext ----------------- ciphertext
public key
decryption
Ciphertext ----------------- plaintext
private key
Message Digest
Also known as “hash function” or “one-way
transformation”.
Transforms a message
of any length and
computes a fixed
length string.
Need of Digest-
Alisha could just encrypt her name, and then
Bijay could decrypt it with IMAGE