1. Encryption

2. What is Encryption? Encryption is the process of converting plain text into cipher text, with the goal of making the text unreadable

3. Three Types of Encryption Symmetric or single Key Asymmetric or two key Hash or No key

4. Symmetric Encryption Uses a single key to both encrypt and decrypt the text.

5. Symmetric Encryption Symmetric cryptography is sometimes called "secret-key cryptography“

6. How Symmetric Encryption Works In symmetric key encryption, two people first agree on a pass phrase (or password). The encryption software then converts that pass phrase into a binary number. The software then uses that number (key) to encrypt all outgoing messages. The mathematical code for encrypting the message is called an algorithm.

7. Asymmetric Encryption Overcomes the shortfalls of symmetric encryption by using two keys: a public and a private key Used by (CA) Certificate Authority The CA issues an encrypted digital certificate containing the applicant's public key and a variety of other identification information.

8. Asymmetric Encryption a public key is known to everyone and a private or secret key known only to the recipient of the message.

9. Hash Functions One way functions because they perform one way transformation of the information that is irreversible

10. Hash Functions Take a block of data as input, and produce a hash or message digest as output.

11. Comparison of Symmetric and Asymmetric Symmetric encryption is faster. One disadvantage in symmetric encryption is that both the sender and the recipient must have an access to (same) encryption key. The key can be distributed personally, for instance, in a diskette, or it can be delivered encrypted (asymmetric encryption) or it can be distributed in some other secure way.

12. Using a combination A combination of both Symmetric and Asymmetric can be used for optimum performance.

13. Hash Functions Because asymmetric cryptographic algorithms are slow and can only encrypt blocks smaller than their key size, when computing digital signatures, it is interesting to sign a cryptographically strong message digest instead of the whole message

14. Digital Certificate

15. An attachment to an electronic message used for security purposes. The most common use of a digital certificate is to verify that a user sending a message is who he or she claims to be, and to provide the receiver with the means to encode a reply.

16. Process An individual wishing to send an encrypted message applies for a digital certificate from a Certificate Authority (CA). The CA issues an encrypted digital certificate containing the applicant's public key and a variety of other identification information. The CA makes its own public key readily available through print publicity or perhaps on the Internet.

17. Certificate Authority The recipient of an encrypted message uses the CA's public key to decode the digital certificate attached to the message, verifies it as issued by the CA and then obtains the sender's public key and identification information held within the certificate. With this information, the recipient can send an encrypted reply.

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