Good morning Professor @gbenga. Thank you so much for this lecture. I'm enlightened. I've been able to learn alot about security on Cryptocurrency blockchain. Here's my homework submission https://steemit.com/hive-108451/@graciee20/the-steemit-crypto-academy-week-5-task-gbenga-a-post-about-a-security-problem-with-cryptocurrency-by-graciee20