2. Why cryptography?
• Authentication: The process of proving one's identity.
(The primary forms of host-to-host authentication on
the Internet today are name-based or address-based,
both of which are notoriously weak.)
• Privacy/confidentiality: Ensuring that no one can read
the message except the intended receiver.
• Integrity: Assuring the receiver that the received
message has not been altered in any way from the
original.
• Non-repudiation: A mechanism to prove that the
sender really sent this message.
3. What is cryptography?
• Cryptography derived its name from a Greek word called
"krypto's" which means "Hidden Secrets".
• Cryptography is the practice and study of hiding information. It
is the Art or Science of converting a plain intelligible data into
an unintelligible data and again retransforming that message
into its original form.
• Cryptography enables you to store sensitive information or
transmit it across insecure networks so that it cannot be read
by anyone except the intended recipient.
• It provides Confidentiality, Integrity, and Accuracy.
5. What Is Encryption?
• In cryptography, encryption is the
process of encoding a message or
information in a way that only
authorized parties can access it and
those who are not authorized
cannot.
6. what is Decryption?
• Decryption is the process of
transforming data that has been
rendered unreadable through
encryption bck to its unencrypted
form.
7. What is a cryptographic key?
• A key is a string of characters used
within an encryption algorithm for
altering data so that it appears
random. Like a physical key, it locks
(encrypts) data so that only someone
with the right key can unlock (decrypt)
it.
• plaintext + key= ciphertext
8. .
• Two kinds of cryptosystems:
Symmetric:
• Uses the same key (the secret key) to
encrypt and decrypt a message.
Asymmetric:
• Uses one key (the public key) to encrypt
a message and a different key (the
private key) to decrypt the message.xt:
Data that can be read and understood
without any special measures.
