diff --git a/README.md b/README.md
index 9bce184..bda2010 100644
--- a/README.md
+++ b/README.md
@@ -283,9 +283,6 @@ Courses | Duration | Effort | Prerequisites
 `unsupervised learning`
 `OpenGL`
 `raytracing`
-`block ciphers`
-`authentication`
-`public key encryption`
 `and more`
 
 Courses | Duration | Effort | Prerequisites
@@ -293,7 +290,6 @@ Courses | Duration | Effort | Prerequisites
 [Databases](https://lagunita.stanford.edu/courses/DB/2014/SelfPaced/about)| 12 weeks | 8-12 hours/week | some programming, basic CS
 [Machine Learning](https://www.coursera.org/learn/machine-learning)| 11 weeks | 4-6 hours/week | linear algebra
 [Computer Graphics](https://www.edx.org/course/computer-graphics-uc-san-diegox-cse167x)| 6 weeks | 12 hours/week | C++ or Java, linear algebra
-[Cryptography I](https://www.coursera.org/course/crypto)| 6 weeks | 5-7 hours/week | linear algebra, probability
 [Software Engineering: Introduction](https://www.edx.org/course/software-engineering-introduction-ubcx-softeng1x) | 6 weeks | 8-10 hours/week | Software Construction - Object-Oriented Design
 [Software Development Capstone Project](https://www.edx.org/course/software-development-capstone-project-ubcx-softengprjx) | 6-7 weeks | 8-10 hours/week | Software Engineering: Introduction