Authorization

For example: The school students Alice and Bob can view (read) their own unofficial transcripts, and Serena, the school principal, can view any student's unofficial transcript. The following statements are true:

• access(Alice, alice_transcript.pdf, read) = yes
• access(Bob, bob_transcript.pdf, read) = yes
• access(Alice, bob_transcript.pdf, read) = no
• access(Bob, alice_transcript.pdf, read) = no
• access(Serena, alice_transcript.pdf, read) = yes
• access(Serena, bob_transcript.pdf, read) = yes

Quick Recap Questions:

1. Why is: access(Alice, bob_transcript.pdf, read) equal to 'no'?
2. Why is: access(Serena, alice_transcript.pdf, read) equal to 'yes'?