It this fast pitch, blockchain technology and its potential applications are presented. We will explore so called decentralized transparent immutable yet secured applications using the blockchain technology and will describe a novel approach of “proof of X” such as proof of identity, proof of college degree and proof of academic achievements. The project prototype of a personal archive service system (PASS) is demonstrated. Personal archive is defined as a collection of various artifacts that reflect personal portfolio as well as personal unique identifications. Personal portfolio is in addition to a simple statement of personal achievement. It is an evidentiary document designed to provide qualitative and quantitative chronically documentation and examples. The pitch moves on to focus on security concerns, risks and challenging. Blockchain technology has been bringing cryptography to individuals who are in turn as value investors in the internet with a clear time sequence, not just any information consumers. But, it is also coupled with various threats and concerns. We will discuss issues inherited from the current blockchain technology such as scalability, efficient and block sizes. We will also talk over a possibility of altering blocks even without over 50% mining power, low resource eclipse attacks and other forms of cheating. We will also present in the end a challenging case of cleaning poisoned blocks.