OKX Blockchain 60 Lectures | Episode 12: Cryptography in Blockchain (Part 2)

"OKX Blockchain 60 Lectures" is a blockchain educational animation series jointly produced by OKX and Sina Tech. Designed for users with zero knowledge of blockchain, it uses articles and animated videos to vividly explain blockchain concepts through 5 major sections and 60 key points, covering concepts, technology, and applications. The content of this episode was guided by Lou Jiyue, founder of Token Mania.

Hello everyone, I'm Xiao K. Today we're going to talk about: "Cryptography in Blockchain (Part 2)".

As we mentioned before, blockchain mainly relies on two cryptographic algorithms: hash algorithms and asymmetric encryption. Today, we'll explain what "asymmetric encryption" is in blockchain cryptography.

Simply put, asymmetric encryption is a special method used to encrypt content. But before explaining asymmetric encryption specifically, we need to cover some other fundamentals of cryptography:

Currently, encryption and decryption methods in cryptography can be mainly divided into two categories: symmetric encryption and asymmetric encryption. Both encryption systems have the same components: encryption algorithm, encryption key, and decryption key.

For example, in our daily lives, we constantly use keys and locks. The key we use to open doors is what we call a secret key in cryptography, while the lock is the encryption/decryption algorithm.

In an encryption/decryption system, the algorithm itself is fixed and generally publicly known, while the key is something more private. During encryption, we use the encryption algorithm and encryption key to encrypt the plaintext (the content to be encrypted) to obtain ciphertext (the encrypted content). The decryption process is the opposite: we use the decryption algorithm and decryption key to decrypt the ciphertext and recover the plaintext.

Methods that use just one key for both encryption and decryption, like a lock and key, are called symmetric encryption.

Conversely, when encryption and decryption use different keys, this method is called asymmetric encryption. Asymmetric encryption is special—it generates two keys. The core one is called the private key, which we keep ourselves. The other is made public, called the public key.

They have a unique property: content encrypted with the private key can be decrypted and read using the public key, and vice versa—content encrypted with the public key can also be decrypted and read with the private key, much like a twin's telepathy.

The main purpose of asymmetric encryption in blockchain is not to protect content privacy, but to prevent identity impersonation.

For example, when we conduct a transaction on a blockchain network, I have no way to confirm whether it is really you conducting the transaction. At this point, I can ask you to send your digital signature (a piece of content encrypted with your private key), and then I can decrypt it using the publicly available public key.

Since the private key is held only by you, if I can successfully decrypt it with the corresponding public key, it confirms that you are the one performing the operation. If it cannot be decrypted, it means someone else has stolen your identity. This solves the problem of proving "I am me, and this is my transaction."

Overall, cryptography is the most fundamental element in blockchain networks. It not only protects the entire network's security but also solves many proof-related problems in transactions. Perhaps with the emergence of new technologies like quantum computing, some may question its security. However, it's important to note that cryptography also evolves with the times. If the day truly comes when quantum computing becomes commercially viable, blockchain cryptography will undoubtedly become an even more secure solution.

Special thanks to Teacher Lou Jiyue for her assistance and guidance on the content of this episode.

Disclaimer

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