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FBI added secret backdoors to openBSD IPSEC

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    #32
    uprising2
    Closed Accounts Posts: 1,627 ✭✭✭uprising2


    gizmo wrote: »
    This example is nice and easy to follow.

    As you can see, the receiver will have a copy of the key which they will use to decrypt the message.



    Key point: A stream cipher is essentially a chained block cipher with a block size of 1 (either 1-bit or 1-byte). It generates a keystream against which it XORs the plaintext, operating much like a one-time pad, though less secure in theory but more secure in practice.
    http://www.linuxsecurity.com/resource_files/documentation/hacking-dict.html

    EDIT:
    I fully appreciate the very high standards of OTP, but computers are constantly evolving, more powerful,faster, etc, I'm sure we all had a clugger that took 2 hours to simply start up, but things have changed, suppose having something much more advanced than rainbow tables, 10,000 of the fastest processors currently available connected and working in unity, 1,000,000GB's or so RAM, a possible combination file of 1,000's of TB's, (I said imagine!), how long would you expect it to crack One Time Pad?
    Hacking – Brute Force & Rainbow Table explained
    Memory Space Trade Off
    It is a situation in which time taken for processing can be reduced at the cost of space and vice versa. To make it very clear, lets see this again with the help of an example. In the previous example, we can process the different combination before hand and then store them in a file. And when you need to break a password, combinations are retrieved from that file and this lessens the load on the processor. The only time consumption in this case is the retrieval of data from that file. This file is what is known as a Rainbow Table. It can break passwords in a few minutes and in even a few seconds depending how strong is the password. It can be obtained from the World Wide Web but beware of its size. Its size is in GBs.
    http://blog.ashfame.com/2007/12/hacking-brute-force-rainbow-table-explained/


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    #33
    gizmo
    Registered Users Posts: 8,405 ✭✭✭gizmo


    uprising2 wrote: »
    Key point: A stream cipher is essentially a chained block cipher with a block size of 1 (either 1-bit or 1-byte). It generates a keystream against which it XORs the plaintext, operating much like a one-time pad, though less secure in theory but more secure in practice.
    http://www.linuxsecurity.com/resource_files/documentation/hacking-dict.html

    EDIT:
    I fully appreciate the very high standards of OTP, but computers are constantly evolving, more powerful,faster, etc, I'm sure we all had a clugger that took 2 hours to simply start up, but things have changed, suppose having something much more advanced than rainbow tables, 10,000 of the fastest processors currently available connected and working in unity, 1,000,000GB's or so RAM, a possible combination file of 1,000's of TB's, (I said imagine!), how long would you expect it to crack One Time Pad?
    Never, because despite your constant protestations the encryption has been mathematically proven to be undecryptable when implemented correctly. I have already shown in the example above that finding a solution isn't really hard, the problem is, you'll never know if it's the right one regardless of how fast computers become.


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