The Matasano Crypto Challenges are a set of 48 practical programming exercises that Thomas Ptacek and his team at Matasano Security have developed as a teaching tool. The challenges cover a wide range of topics in cryptography and are designed to help developers improve their skills in application security. The challenges are not documented anywhere, but they are designed to be tractable and can be completed with diligence, coffee, and graph paper. The challenges cover topics such as encryption, decryption, and hashing, and are designed to help developers improve their skills in application security. The challenges are a great way for developers to improve their skills in cryptography and application security, and are particularly recommended for developers who have no experience with application security.