1. A simple protocol - 1 A B rB || Are you OK? rB || Yes, I’m OK
MACK ( rB || Yes, I’m OK )
Introduction to Cryptography and Security Mechanisms 2005

2. A simple protocol - 2 A B Are you OK? Bob || Yes, I’m OK
SigA ( Bob || Yes, I’m OK )
Introduction to Cryptography and Security Mechanisms 2005

3. A simple protocol - 3 A B rB || Are you OK? rB || Bob || Yes, I’m OK
SigA ( rB || Bob || Yes, I’m OK )
Introduction to Cryptography and Security Mechanisms 2005

4. A simple protocol - 4 A B TB || Are you OK? TB || Bob || Yes, I’m OK
MACK ( TB || Bob || Yes, I’m OK )
Introduction to Cryptography and Security Mechanisms 2005

5. A simple protocol - 5 A B Are you OK? Bob || Yes, I’m OK
MACK ( TA || Bob || Yes, I’m OK )
Introduction to Cryptography and Security Mechanisms 2005

6. A simple protocol - 6 A B TB || Are you OK?
TA || TB || Bob || Yes, I’m OK
MACK ( TA || TB || Bob || Yes, I’m OK )
Introduction to Cryptography and Security Mechanisms 2005