4.18 Consider the following protocol: A KDC: IDA 7IDB 7N1 KDC A: E(Ka, [KS 7IDB 7N1 7E(Kb, [KS 7IDA])) A B: E(Kb, [KS 7IDA]) B A: E(KS, N2) A B: E(KS, f(N2)) a. Explain the protocol. b. Can you think of a possible attack on this protocol? Explain how it can be done. c. Mention a possible technique to get around the attack-not a detailed mechanism, just the basics of the idea. Note: The remaining problems deal with a cryptographic product developed by IBM, which is briefly described in a document at this book's Web site in IBMCrypto.pdf. Try these problems after reviewing the document. | |
| View Solution | |
| << Back | Next >> |