What is cryptography?

Cryptography is the combination of two ancient Greek terms "Crypto" and " graphein" meaning " Hidden" for the former and " To write" for the latter, So in simple terms, cryptography is a method of securing data during a communication process.

Let me give an example, I want to send you a private mail or message, I can use my private key to encrypt that message so that it is unreadable to any third party, and I also verify the message with the recipient's public key, let's call the public key your address, then the owner of that public key I used can then reveal the message into a readable format called plain text using their private key.

Are there types of cryptography?

Yes, there are three main types of cryptography ;

• Symmetric key cryptography which is also called "Secret key Cryptography", uses a single key to encrypt a message or to make that message secret, so giving access to the person with that private key to decrypt it. In cryptography when you send a private message, the data or information is called plain text because this is readable. Cryptography algorithms turn that plain text which is read into ciphertext, and the receiver has to decode that secret message using their private key.
• Asymmetric key cryptography uses a two-key method, a key for encryption and another key for decryption, the key used for encrypting a message cannot be used for decrypting that message, there comes the private key, and the public key, the public key is used for encrypting the plain text to cipher text(unreadable text) while the private key of the receiver is used to decode or reveal the ciphertext to plain text.

• Hash Functions uses a type of hashing algorithm that produces strings of letters and numbers which are unique to every data produced, for every change in data a new hash key would be created to ensure transparency, So if you send data containing the number of oranges you took, a hash would be generated, and if you are to update that data a new hash would be generated, there are different types of hash functions, but the current hash function used in Blockchain is called SHA 256, secured hashing algorithm, it is a type of function that turns your input or any input no matter the length into 256 bits.

  So which of the three does the blockchain use?

The blockchain uses the asymmetric key and the hash key function to ensure transparency, and immutability, and also to improve security.

Is there any future for cryptography in Blockchain?

Yes, in our present world, we have been faced with cyberattacks ranging from hacking to information theft, we cannot say that they weren't any security, Symmetric key cryptography was the primary source of security, but with asymmetric key cryptography and hash functions that uses SHA256 to create a unique string for each data put on the block, this would ensure the security of information on the blockchain.

So, is that where the Crypto in Cryptocurrency comes from?

Yes, the crypto in cryptocurrency means secret, using cryptography security to ensure this.

Is there a real-world use case for cryptography in Blockchain?

Yes, there is. Imagine a situation in which you go to the bank and write down your signature, your signature needs to be verified that it is yours, for security purposes, and your signature needs to be owned by you, like a unique identifier, and also ensure that it cannot be forged, and also it cannot be denied by you later, So cryptography works in a similar format.

Using the public key cryptography as a tool, there's a verification or an ownership identifier which is your public key, and there is also a unique hash function for each data to ensure immutability and also a private key to ensure that there's no future denial.

Is there a Reason why Symmetric key cryptography is not used? Does it have its shortcomings?

Yes, Symmetric key cryptography has its limitations because it uses only a single key for encryption, which must be shared with anyone that wants to decrypt the message making it vulnerable to cyber-attacks.

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