Crypto Discussion by Pamela Cutter https://padlet.com/pam_cutter/9h6won0wctp0 Reflections and comments on Chapters 1 and 2 of Crypto en-us 2017-01-20 15:52:00 UTC 2017-01-20 20:56:55 UTC hello@padlet.com I found the explanation of the key size on page 57 to be very interesting. "each bit in a binary key is a like a fork in the road that a codebreaker must negotiate in order to get to the destination of the correct combination of ones and zeros." With all the talk about the size of the key, I am curious to know if 56 bits was the optimal size and how they chose that number? Could they have gone to a smaller bit size or would one or two bits smaller compromised the data? math450_1 https://padlet.com/pam_cutter/9h6won0wctp0/wish/148473581 From the reading, the key size for DES was originally 128 bits, was pared down to 64, which would have been sufficiently difficult to break by brute force methods. There is no clear answer as to why the key was further reduced to 56 bits, other than that the NSA asked IBM to do so. It is speculated that this reduction allowed the NSA to crack the code with their computational power, but left the encryption strong enough that their enemies and external powers could not.

As to the key strength, it was certainly not an optimal size from a security standpoint. It could not be reduced any further without making brute force decryption laughably easy. In fact, had the key size remained at the originally proposed 128 bits, it may still be a viable encryption standard, as no great weakness has been found  in the algorithm (other than the small key size).

-Owen Galvin]]> 2017-01-20 20:14:11 UTC https://padlet.com/pam_cutter/9h6won0wctp0/wish/148473581 Do we have much privacy today? I thought this statement was inaccurate because a lot of our data is communicated through social media services like facebook, e-mail etc. Our smartphones even retain the knowledge of what route we need to take on a particular day. Lots of our information is accessible to outsiders but we've adjusted ourselves to think that all our information is held in the highest order of privacy. Thoughts? math450_1 https://padlet.com/pam_cutter/9h6won0wctp0/wish/148476861
I think the difference between the situation in the 1980s and today is that privacy is available if desired today; social media and other outlets do cause the loss of privacy for many, however, this is a deliberate loss of privacy (there is no Eve in this situation who is trying to intercept a message). In contrast, prior to the late 1980s, cryptography algorithms were not publicly available, and email senders did not realize that sending an email caused an immediate loss of privacy of any information contained in that email (book likened it to one step before broadcasting it). In that case, any person (Eve/NSA) could intercept the message, causing an unintentional loss of privacy. Today, people are willingly giving away information on social media and not encrypting information (despite the existence of cryptographic algorithms); the loss of privacy (by spreading information for others to know) is the reason people use social media (and why they don't encrypt information).

-Rao Li]]> 2017-01-20 20:29:10 UTC https://padlet.com/pam_cutter/9h6won0wctp0/wish/148476861 How much security do people deserve from the government? math450_1 https://padlet.com/pam_cutter/9h6won0wctp0/wish/148477122 2017-01-20 20:30:06 UTC https://padlet.com/pam_cutter/9h6won0wctp0/wish/148477122 Kahn’s book, “Codebreakers,” was heavily opposed by the NSA, "innumerable hours… were spent in an attempt to sandbag the book.” (pg. 23) So much so that he was placed on a watch list, where, “eavesdroppers” were able to monitor his mail and conversations. This makes me wonder if this still goes on nowadays, and what an individual would have to do in order to be “watched.” math450_1 https://padlet.com/pam_cutter/9h6won0wctp0/wish/148477738 2017-01-20 20:32:56 UTC https://padlet.com/pam_cutter/9h6won0wctp0/wish/148477738