M. Bishop, "An Application of a Fast Data Encryption Standard Implementation," Computing Systems 1(3) pp. 221-254 (Summer 1988).  Home/Search   Document Not in Database   Summary   Related Articles   Check

....to the remote machines as if it were an authorized user performing a standard remote operation. ################## Strictly speaking, the password is not encrypted. A block of zero bits is repeatedly encrypted using the user password, and the results of this encryption is what is saved. See [4] and [19] for more details. The hosts.equiv and per user .rhosts files referred to later. 6 To defeat future such attempts requires that the current remote access mechanism be removed and possibly replaced with something else. One mechanism that shows promise in this area is the Kerberos ....

Bishop, Matt, "An Application of a Fast Data Encryption Standard Implementation," COMPUTING SYSTEMS: THE JOURNAL OF THE USENIX ASSOCIATION, vol. 1, no. 3, pp. 221-254, University of California Press, Summer 1988.

....with any reasonable effort. Performance of the initial sequence number generator is not a problem. New sequence numbers are needed only once per connection, and even a software implementation of DES will suffice. Encryption times of 2. 3 milliseconds on a 1 MIPS processor have been reported [13] . An additional defense involves good logging and alerting mechanisms. Measurements of the round trip time essential for attacking RFC compliant hosts would most likely be carried out using ICMP Ping messages; a transponder function could log excessive ping requests. Other, perhaps ....

Bishop, M. An Application of a Fast Data Encryption Standard Implementation . Technical Report PCS-TR88-138, Department of Mathematics and Computer Science, Dartmouth College, Hanover, NH. 1988.

....of zero bits, using the user supplied password as a key. The transformation is normally an altered version of DES encryption, performed 25 times. The transformation is sufficiently slow so that exhaustive keyspace attacks are currently not practical, although fast implementation such as deszip,[3] can perform many thousands or tens of thousands of comparisons per second. In UNIX, the encrypted version of the password has traditionally been kept in a world readable file; the safety of the passwords has been protected by the time complexity of an exhaustive attack. Thus, one of the factors ....

M. Bishop. An application of a fast data encryption standard implementation. Computing Systems, 1(3):221--254, 1988.

....assembly language that the compiler produces. Because the VAX compiler is reluctant to use all of the processor registers, speed des on the VAX uses a SED script that goes through the assembly code and replaces certain memory references with register references. Fast DES implementations by Bishop[1] and Karn[5] each utilize most of the suggestions above. 4 The Speed Des Implementation The DES algorithm has 48 bit, 56 bit and 64 bit wide paths. This program was written with 32 bit wide CPU paths in mind, so the DES data path is broken into high and low pieces of 4 bytes each. Since even 48 ....

....The speed des implementation is faster than any other known DES implementation (except possibly an implementation by Davio see below) Others have also implemented high speed DES functions and this section discusses their implementations. Matt Bishop wrote his deszip code at Dartmouth[1]. The deszip code has a variety of options to allow various speed size tradeoffs. Keys can be computed either the standard way or with a permutation per subkey. The SPE lookups can be done 6 or 12 bits at a time. It is also sophisticated about taking advantage of the machine architecture to ....

Matt Bishop, "An application of a fast data encryption standard implementation", Computing Systems, 1(3):221--254, Summer 1988.

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M. Bishop, "An Application of a Fast Data Encryption Standard Implementation," Computing Systems 1(3) pp. 221-254 (Summer 1988).

....are specific to his design and cannot be implemented in speed crypt. The fdes program is designed to run well on e[ VAX. It runs very well on the VAX, but not as well on other machines. Matt Bishop wrote his deszip code at Dartmouth College and the Research Institute for Advanced Computer Science[2]. The code has e[ variety of options to allow various speed size tradeoffs. Keys can be computed either the standard way or with e[ permutation per subkey as speed crypt does. The SPE lookups can be done 6 or 12 bits at e[ time. It is also sophisticated about taking advantage of the machine ....

....VAX compiler is reluctant to use all of the processor registers, speed crypt on the VAX uses a SED (UNIX Stream EDitor) script that replaces certain memory references with register references in the assembly code. A. 3 Implementation Alternatives Fast crypt implementations by Baldwin[i] Bishop[2] and Mitchell[8] each utilize most of the suggestions above. Fast DES implementations also use similar techniques[4] Speed crypt has a technique for the E expansion that can double the speed of an implementation on 32 bit RISC machines. The questor code was written by Donald Mitchell at Bell ....

Matt Bishop. An application of a fast data encryption standard implementation. Computing Systems, 1(3):221-254, Summer 1988.

....of auto read. if (auto read(AUTO ALL) f there was a previous state, state is initialized g else f no previous state, set state to initial values g Appendix A shows a sample program which uses all the features described in this section. We have also rewritten the password cracker of [Bis88] using HMF. The password cracker is a good test program for HMF because it includes one big loop which provides a natural checkpoint location after each iteration, and the program runs a long time without any user interaction. 6 Conclusions We have examined the feasibility of process migration ....

Matt Bishop. An application of a fast Data Encryption Standard implementation. Computing Systems, 3(1):221--254, Summer 1988.

....passwd was extended to change login shells, user information, to handle password aging, and extended in other ways. Unfortunately, rigorous password checking was not one of them; the precise reasons for this are not clear. After the completion of a rather powerful password cracking program deszip [1], the author of that program decided to develop and distribute a countermeasure, so that sites which obtained deszip would be able to insulate their system against attacks from other password cracking programs. The original version of passwd was distributed with deszip as well as separately; it ....

Bishop, M., "An Application of a Fast Data Encryption Standard Implementation," Computing Systems 1(3) (Summer 1988) pp. 221-256.

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M. Bishop. An application of a fast data encryption standard implementation. Computing Systems: The Journal of the Usenix Association, 1(3):221--254, Summer 1988.

No context found.

Matt Bishop. An application of a fast data encryption standard implementation. Computing Systems, 1(3):221--254, Summer 1988.

No context found.

Matt Bishop, "An Application of a Fast Data Encryption Standard Implementation," Computing Systems,vol. 1, no. 3, pp. 221-254, Summer 1988.

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