Discrete Mathematics
Hans Georg Schaathun

Introduction to Cryptography

Extra Material (Week 3)

The Modulo Operator MPEG4 / OGG
This is an old and longer version of the video on the modulo operator. I think it is too long, and therefore it has been superseded, but it does offer a different angle. Watch it if you find it useful.
12:36 PDF p. 90-93 p. 293
Elaboration on modular arithmetics Time Slides Stein et alRosen
Modular addition MPEG4 / OGG 5:37 PDF p. 95-99 p. 243+
Modular multiplication and rings MPEG4 / OGG 7:26 PDF p. (95-)98-101 p. 243+
Modular Subtraction MPEG4 / OGG 4:14 PDF ?? ??
More on modular arithmetics Time Slides Stein et alRosen
Multiplicative Inverses MPEG4 / OGG 10:55 pre-slides
p. 105-109 p. 273-275
The Affine Cipher MPEG4 / OGG 14 min. PDF N/A p. 293
Rings MPEG4 / OGG This video elaborates on modular arithmetics by introducing rings. This should make sense at this stage of the syllabus, and was given at this stage in previous years. This year we shall focus on practicing the modular arithmetics first, and introduce rings when we get to finite fields later on. 13:21 PDF p. 98-101 p. 808+

Hans Georg Schaathun / hasc@hials.no