Activity: Determining Key Usage

This activity requires you to determine which keys are used to secure e-mail and Web transactions for the purposes of digitally signing and encrypting data transmissions.

Scenario

Eva Corets and Don Hall work for competing movie studios. They want to send encrypted and digitally signed messages to each other to prevent their e-mail administrators from reading the content of the e-mail messages. They are currently codeveloping a screenplay and want to ensure its authenticity, integrity, and protection as it's sent between their computers.

Questions

Here are some questions about this scenario. The answers to these questions are located in the appendix.

1. If Eva wants to digitally sign a message she is sending to Don, which key is used to encrypt the message digest that protects the message?
   1. Eva's private key
   2. Eva's public key
   3. Don's private key
   4. Don's public key
2. When Don receives Eva's digitally signed message, which key is used to decrypt the message digest that protects the message?
   1. Eva's private key
   2. Eva's public key
   3. Don's private key
   4. Don's public key
3. If Don wants to encrypt a message he is sending to Eva, which key is used to encrypt the contents of the e-mail message?
   1. Eva's private key
   2. Eva's public key
   3. Don's private key
   4. Don's public key
4. When Eva receives Don's encrypted e-mail message, which key does Eva use to decrypt the encrypted e-mail message?
   1. Eva's private key
   2. Eva's public key
   3. Don's private key
   4. Don's public key
5. Eva wants to both digitally sign and encrypt an e-mail message that she is sending to Don. Which two keys are used to digitally sign and encrypt the e-mail message?
   1. Eva's private key
   2. Eva's public key
   3. Don's private key
   4. Don's public key
6. When Don receives the digitally signed and encrypted e-mail message from Eva, which two keys does Don use to decrypt the message digest and the encrypted message from Eva?
   1. Eva's private key
   2. Eva's public key
   3. Don's private key
   4. Don's public key

Answers