Summary

• In systematic encryption, clear text is turned into ciphertext, and then decrypted back into clear text, by use of keys.

• Asymmetric encryption uses either the same algorithm, or different but complementary algorithms, to scramble and unscramble data.

• The Diffie-Hellman algorithm provides a way for two parties to establish a shared secret key that only they know, while communicating over an insecure channel.

• A hash algorithm is a formula used to convert a variable-length message into a single string of digits of a fixed length.

© 2004 Cisco Systems, Inc. All rights reserved. BCRAN v2.1—5-7

Quiz

Use the practice items here to review what you learned in this lesson. The correct answers are found in the Quiz Answer Key.

Q1) Which technology can provide authentication?

B) Digital Signatures

C) Diffie-Hellman

Q2) Symmetric encryption requires that the same key be used during encryption and decryption.

A) true

B) false

Q3) Which of the following is a form of asymmetric encryption?

A) shared secret

Q4) Diffie-Hellman provides for confidentiality and authentication.

A) true

B) false

Q5) What is the key size difference between HMAC-MD5 and HMAC-SHA-1?

0 0

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