DONE BY
1- Shahed Mehdawi (2212202)
2- Nancy Althahabi (0204934)
Dr. Oraib AbuAlganam
CIPHER PROTOCOL
Project cryptography (1)
❖The purpose of this protocol and how it works
- We designed this protocol to transmit an information between 4 parties
so that is this information cannot be seen by anyone except the ones who
have the same shared key.
- It can be used by any Organization when the manager wants two different
information from two different departments in another branch of the
Organization or in another different Organization from another country
(Police Center, Embassy Etc..).
- So how those 4 parties will transmit the information exactly?
This is when you are the Admin that the manager needs the two
information from, So you have to connect with Employee1 from
Department1 to get the first information, then you have to connect with
Employee2 from Department2 to get the second information,
Then finally you have to send those two information to your manager
AND ALL OF THAT MUST DONE SECRETLY
- So what do we mean with Secretly?
1- That the messages between the manager and the admin no one can see
except them,
2- The messages between the admin and employee1 no one can see except
them, and the same for the admin with employee2.
3- So that employee1 and employee2 won’t leak secret information from
their departments to each other or even to the attacker
(only the manager and the admin can See them)
And here we conclude that we need 3 SHARED KEYS to achieve that
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❖Scenario of the protocol
-
A new manager in Saudi-Arabia’s Company works in
Scholarships Department wanted a (list of Scholarships
students who went to study in Jordan’s Universities with their
passport ID’s and the fees of scholarships) of the 2018 year
- So here he had to connect with the Admin of Saudi-Arabia
Embassy in Jordan to ask him about the two information he
needs as above.
- The Admin had to connect with two different departments of the
embassy to bring the information.
- First information: Students with their passport ID’s
from the Student record department.
- Second information: fees of Scholarships
from the Finance department.
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❖The (Unsafe) protocol that has a vulnerability:
- It doesn’t fulfill the Authentication goal because the Shared key was
encrypted with the public key of the Sender. Which can’t be decrypted by
anyone but the Sender itself.
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❖Protocol simulation
❖Attack simulation
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❖The solved (Safe) protocol
• So what did we do to solve the vulnerability?
- We encrypted the Shared key with private key of the sender
And here we fulfill the Authentication! And also we guarantee the
digital signature of the sender so the receiver will know who they’re
talking with.
• The whole message was encrypted with the public key of the receiver
so that is no one can open it except the receiver so here we fulfill the
confidentiality
• Our protocol can make you guarantee Three things:
1- Authentication
2- digital signature
3- confidentiality
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