Syllabus | Homework rules | Code of honour |
2003-02-20: For information on Pseudorandom Generators, see Chapter 5 and sections on LFSRs in Chapter 6 in Handbook of Applied Cryptography (HAC) (link below). For Zero-Knowledge and identification, see Chapter 10 in HAC. I have handed out material from the previous edition of Stinson (Chapter 11) on Secret Sharing. Copies can be found outside the student office at Nada.
Also, note that for homework set 3 one of the tasks is to implement a program that solves the discrete log problem, not just to find out the discrete log of your personal number.
2003-02-13: Homework set 3 posted below. The problems posted as a preview on 2003-02-10 have been removed from the web page as they are available in the complete homework set. Good luck!
2003-02-10: Parts of Homework set 3 available below.
2003-02-10: The fastest AES (12.9 MB/s) was handed in by Mattias de Zalenski and the fastest DES (746 kB/s) was handed in by Patrick Zeits.
2003-02-04: The file rsa3 used in homework set 2 has been fixed.
There is a misprint in Stinson in algorithm 5.11
(Wiener's algorithm). The call to Euclidian Algorithm should
have the parameters reversed, i.e.,
Euclidian Algorithm(b,n)
and the first line of the for-loop should not be executed for
j=1 since c_{1}=0 in this case.
2003-01-29: Since it has been requested by more than one person, I have added a couple of sample files for aes and des below. Also: problem set 2 now posted below.
2003-01-22: Homework set 1 -- the seven second time limit for Des and Aes is hereby extended to 10 seconds.
And here are the instructions for how to turn in your DES or AES program.
2003-01-21: Handed out Matsui's article on linear cryptanalysis of DES.
2003-01-16: The Suns bunch11--bunch20 can be used if you want to run programs for a while. You can telnet or ssh to them and use nohup and nice (and maybe kauth) to start batch jobs and have them print results to file while you are busy doing other things. However, I doubt that you will need to use them during the first homework set.
2003-01-15: First homework set handed out. Link on this page.
2003-01-09: The links above should work now.
res checkin krypto03
course join krypto03
If you do not do this your results cannot be reported and you will miss vital information related to the course.
Please note the rules that apply to the homework. Be sure to read both the homework rules and the code of honours before you start working on the problems!
Files related to DES: s1 s2 s3 s4 s5 s6 s7 s8 ip p esel pc1 pc2 desexempel
The following files are the cleartext and ciphertext when using the DES and the key 0110233245546776: des.in and des.ut.
Files related to AES: subbytes aesexempel. Also, FIPS-197 (see links at the bottom of the page) contains per round traces of AES-encryptions which is helpful for debugging purposes.
The following files are the cleartext and ciphertext when using the AES and the key 00112233445566778899AABBCCDDEEFF aes.in and aes.ut.
Files related to the Geheim-Schreiber: the plaintext/ciphertext pair, the second ciphertext, and a C-implementation as well as a short description of the Geheim-Schreiber.
Files with ciphertext encrypted using unknown methods: unknown1, unknown2, and unknown3. Please note that the newlines have only been inserted for readability. They are not part of the ciphertext!
Files related to problems in this set: e for problem 3, N for problem 3, and rsa3 for problem 5.
Test for the 55-bit output sha. Please report to me if you think this
is wrong (I could have made a mistake in my own implementation).
Input: 111 7aa 2bb 3ff 222 (as 5 11-bit blocks) Padded: 111 7aa 2bb 3ff 222 400 0 0 0 0 0 0 0 0 0 37 (as 16 11-bit blocks) Output: 6b6 52b 432 3c6 311
The sequences for the pseudorandom generator problem are found here. They have been written as strings of zeroes and ones broken into lines for readability, and to make them reasonably platform independent.
ser01, ser02, ser03, ser04, ser05, ser06, ser07, ser08, ser09, ser10, ser11, ser12, ser13, ser14, ser15, ser16, ser17, ser18, ser19, ser20.
As any book, it has some errors, and on the boks
homepage
there is a link to a list of errors.
Links to errors in the first edition are on the
course page
from the Spring of 2000.
As an alternative, there is "Menezes et al.: Handbook of applied cryptography". This book is available electronicly. Visit its homepage. Study the copyright notice. Note that, regardless of the copyright notice, you may not use a printer at KTH to print out a copy of this book.
Week | Topics |
---|---|
3 | Some classical cryptosystems and cryptanalysis. The notion of security. Provably secure cryptosystems. Basic information theory and entropy. Block ciphers. |
4 | The DES and AES block ciphers. Attacks. Linear (and perhaps differential) cryptanalysis. |
5 | Hash functions, MACs, birthday attacks. Public key cryptography. RSA: definition, key generation, efficiency. Other systems. |
6 | More public key cryptography. Signature schemes. |
7 | Identification schemes. Zero knowledge proofs. |
8 | Guest lecure. Pseudo random number generators. |
F | ti | 15-17 | v 3-8 | Q2 | |
F | on | 15-17 | v 3-5 | E3 | |
F | fr | 10-12 | v 3-8 | E3 |