No one on Earth knows how to reverse the SHA-256 hash function. Yet it’s really easy to compute one-way. You could make billions of dollars if you solved this mathematics problem. SHA-256 might also be the world’s most popular algorithm – it’s computed quintillions of times per second in the race for mining Bitcoin. It has some amazing properties, is useful for digital signatures, cryptography, authentication, and is a central part of the Bitcoin protocol.
Bitcoin and other “crypto-currencies” rely on one-way hash functions like the SHA-256 algorithm to secure the blockchain where all the transactions are kept.
In this video, I explain some of the big-picture ideas behind this one function. Other cryptocurrencies use similar ideas.
Comments, suggestions, or errors? Let me know in the comments, and I’ll fix them in an upcoming follow-up video (coming late July 2019)
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Wikipedia about SHA-256:
Current Bitcoin difficulty:
Big number calculator: