Klaus Pommerening Cryptology

a7Hzq .#5r< kÜ\as TâÆK$ ûj(Ö2 ñw%h: Úk{4R f~`z8 ¤˜Æ+Ô „&¢Dø

This pages contain (large parts of) the manuscript from my lecture course in Cryptology at the University of Mainz. They are mainly written in german. For roughly equivalent material in english I recommand the crypto pages by John Savard, look here.

You could also visit my Bookmarks on Cryptology.

I offer some small programs in Perl or C that are written (i. e. commented) in english:

• Monoalphabetic substitution (in Perl):
  • Subsidiary functions: auxcrypt.pl
  • Encryption: monoalph.pl
  • Decryption: monodecr.pl
• Monoalphabetic cryptanalysis (in Perl):
  • Letter count: count.pl
  • Bigram count: bicount.pl
  • Pattern search in texts or wordlists: pattword.pl
• Polyalphabetic substitution and cryptanalysis (in Perl):
  • Porta-Belaso (= general cipher disk) cipher: porta.pl
  • Kasiski's search for repeated substrings: kasiski.pl
  • Friedman's index of coincidence: coinc.pl
  • Single rotor cipher: rotor.pl
• Transposition (in Perl):
  • Transposition cipher: transp.pl
• A program for the WALSH transform (in C).
• Cryptanalysis of stream ciphers (in C):
  • Cracking linear congruence generators (Plumstead algorithm): lcgcrack.c
  • GNU-MP-Library is here).
  • WIN32-executable, ZIP format (incl. cygwin1.dll).
  • Sample input files: hier, more test examples: 0, 1, 2, 3, 4, 5 (Example 1 extends the first example.)

Furthermore you might be interested in letter frequency tables:

• Letter frequencies in german.
• Letter frequencies in english.
• Letter frequencies in several languages.
• Bigram frequencies in german and english.

EMail to Pommerening@imsd.uni-mainz.de.