CLASSROOM EXCERPT / GARY GENSLER / MIT OPENCOURSEWARE / 2018

meaning you can add a little bit of information to this.

And it's time-stamped.

So these are these blocks being added.

Now, it's secured by cryptography,

because cryptography, remember, is communications

and making sure adversaries can't pick you off.

We're going to learn about hash functions.

And hash functions are a really important part of cryptography,

and initially for databases, and how to search and store

information in databases, but in this circumstance,

hash functions were the way to not only append the next block

to the prior blocks, but really importantly, to compress data,

to make it more manipulable, and to verify it,

and as I've written here, tamper resistance and the integrity.

And then consensus-- so there is a really important part

of blockchain is, how do you decide

who appends that next block?

Because when I went back here, there is block and block.

Each of these blocks, somebody has to decide who appends,

who gets to pick the next block.

And that's what's called consensus protocol.

SOURCE & LICENSE
REAL CLASSROOM VIDEO — SOURCE AND LICENSE

Original: Session 1: Introduction, 15.S12 Blockchain and Money, Fall 2018.
Instructor: Gary Gensler. Publisher and copyright holder: Massachusetts Institute of Technology / MIT OpenCourseWare.
Source: https://ocw.mit.edu/courses/15-s12-blockchain-and-money-fall-2018/resources/session-1-introduction/
Official download: https://archive.org/download/MIT15.S12F18/MIT15_S12F18_lec01_300k.mp4
Original timed captions: https://ocw.mit.edu/courses/15-s12-blockchain-and-money-fall-2018/20bc3a67ada855098f6514ce837a6b0f_EH6vE97qIP4.vtt
License: Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International.
https://creativecommons.org/licenses/by-nc-sa/4.0/

Changes: selected source excerpts (15:48.570–15:59.700, 17:13.859–17:56.490 and 18:30.330–18:49.920); concatenated as three educational chapters; added independent currency graphics, titles, source notices, original English captions and a Chinese translation. No alteration to the instructor's face, voice, performance or original spoken meaning.

The resulting adapted video and associated subtitle files are distributed under CC BY-NC-SA 4.0. They are for noncommercial educational use. They may not be used as commercial promotion under this license. The instructor and MIT do not endorse or sponsor AUREON LAB. The material was recorded in 2018 and is presented as a historical foundational lecture, not as current market analysis.