Assume the following incidences happened years ago before there
Assume the following incidences happened years ago before there were
agreements of cooperation between the US and the Nevis Islands. So, neglect, the recent agreements between the US and the Navis Islands government for your analysis.
Arianna changes banks following her troubles with FNB. At her new bank, National Security Trust (NST), RSA is used as the cryptographic system. Arianna creates a key pair and supplies her public key {eA, nA}, to Fiona, a bank manager of NST and securing her private key {dA, nA} on a thumb drive which Arianna keeps locked in a wall safe at her home. In turn, Fiona, who is designated to handle Arianna’s business, gave Arianna access to a key server maintained by NST so that Arianna can readily obtain Fiona’s current public key {eF, nF} whenever she needs to communicate securely with Fiona.
Things are fine for a few months until Arianna sends Fiona a short message “m” asking about current interest rates on Certificates of Deposit issued by NST. As shown below, she encrypts the message with Fiona’s public key first and then signs with her private key.
C = (meF mod nF )dA mod nA
Where C is the encrypted message and m is the plaintext message.
A few days later, Arianna received a statement that shows a debit of $2,000,000 from her account. On inquiring, she was told that Fiona transferred the money out of Arianna’s account into an account of her own in a bank on the Caribbean island of Nevis, where she moved. When reached via long distance in Nevis, Fiona produced an encrypted message ‘C1’ and corresponding plain text message from Arianna saying:
“Thanks for your excellent service, Fiona. Please transfer $2,000,000 from my account to yours as a token of my esteem and appreciation. Signed, Arianna.”
Arianna files suit against, Fiona, NST and the government of the Nevis, claiming that the message was a forgery sent by Fiona herself, asking for triple damages for pain and suffering. Fiona has responded by claiming that all procedures were followed properly, and that Arianna is filing a nuisance suit.
You have been employed by NST as an expert to assist in the investigation of this matter and help them decide what to do with Arianna issue. You obtain Fiona’s private key from the NST server, and the cipher text C, and calculate
g= (C1eAmod nA)dFmod nF
Where g is the plain text message which was obtained decrypting the cipher text C1, using Fiona’s Private key (dF,nF). Your report to the NST Board of Directors should address the following issues:
From the facts as presented what can be determined about Arianna’s intentions to make Fiona a gift of $2,000,000? How did the fact help you in forming your conclusion?
What is the significance of Nevis Island? Did the significance sway your decision? If yes, why? If no, why?
What is the significance of Arianna’s message to Fiona asking for interest rates?
Assuming NST wishes to continue using RSA as its cryptographic system, what NST and Arianna could have done to protect against this controversy arising?
How to proceed in the litigation?
