Private and Public key in blockchain are an integral part of the technology and crypto wallets. They allow you to send and receive cryptocurrency without requiring a third party to verify the transactions. These keys are part of public-key cryptography (PKC) or asymmetric encryption. 

You can use these keys to send your cryptocurrency to anyone, anywhere, at any time. The public and private keys form a key pair. You can share your public keys in order to receive transactions, but your private keys must be kept private, hence the name “private key.” Anyone who has access to the private keys will also have access to any cryptocurrency associated with those keys.

What is Public key and Private key?

In short, a public key is an address with which you can receive crypto, while a private key is used to authorize transactions.

Public Key

The name “public key” refers to a sequence of random symbols that is available to anyone. You can receive cryptocurrency transactions with the key. It is a cryptographic code that is used in conjunction with a private key. While anyone can send transactions to the public key, the private key is required to “unlock” them and prove that you own the cryptocurrency received in the transaction. As a result, you can freely share your public key without jeopardizing the security of your wallet.

Private Key

A private key allows you to prove ownership by authorizing or signing transactions associated with your public address. These private keys typically differ depending on the type of cryptocurrency. They can take many forms, including 256-character binary codes, mnemonic phrases, 64-digit hexadecimal codes, and QR codes.

Despite the fact that nearly all of them use 256-bit encryption. Bitcoin, Ethereum, Litecoin, and other cryptocurrencies are included. However, regardless of its form, a private key is an astronomically large number. The complexity and length of a private key determine how easy it is for an attacker to carry out a brute-force attack, in which they try out several keys until they find the right one.

Private and Public Key examples

There are differences between public and private keys. The public key is used for encryption, but only a private key can be used to decrypt the data. Crypto wallets are excellent examples of how to use public and private keys. When it comes to wallets, a public key is a user’s address that allows other network participants to send tokens to this wallet. However, if a user wishes to send cryptocurrency from one wallet to another, they will require their private keys to confirm the transaction.

We will be looking at an example of public and private keys below. 

An example of an Ethereum Public key (receiving address)

0x0B28873659607e6999B264A809fc5D8a29F210Ea

An example of an Ethereum Private key

55ff026b9761315f4bb638ec73801f6a18bf8f8acdc78fa7ddf44dcaabba3add

The private key displayed above is associated with the corresponding public key. Hence, importing the above private key into an Ethereum wallet like Metamask generates the public key displayed above. But it is relatively impossible to find a private key with a public key. 

How Public and Private key Works in Blockchain

private and public key in blockchain uses asymmetric encryption, as opposed to symmetric encryption. Asymmetric encryption necessitates the use of both public and private keys. Different keys are used for encryption and decryption using this mechanism. The public key is used to encrypt messages, while the private key is used to decode them.

Understanding how public and private keys interact is essential to understanding how cryptocurrency transactions work. When you say you have cryptocurrency, what you really mean is that you have a private key that proves ownership of that cryptocurrency. Because it is stored on the blockchain, anyone with your public key can verify you as the owner.

How do Blockchains use Private and Public-key Cryptography

When it comes to cryptography in blockchain, there are several methods, which include symmetric encryption, asymmetric encryption, and hashing.

Symmetric Encryption

It is one of the most widely used, simple, and effective encryption methods. The messages are encrypted with a single key, which can be identical or different between parties at the same time. It is then encrypted and sent to a recipient, where it must be decrypted once received and verified.

Asymmetric Encryption

Message encryption and decryption typically involve two keys: a private key and a public key. After a transaction has been requested, public keys are used to verify it. In contrast, a private key is used to decrypt the message or transaction. The idea is to keep the transaction authentic while reducing the risk of a security breach.

Hashing

Hashing is designed to encode the user’s account addresses to encrypt transactions between accounts. To ensure the encryption is secure, random letters and numbers are added to the stored value. That is mainly to mitigate the risks of easy decryption. The “stored value,” on the other hand, refers to the digital fingerprint or hash value after the conversion is complete. 

Difference between Public key and Private key

Both public and private keys’ goal is for one to receive transactions while the other authorizes them, and hence verified transactions can be traced to the owner who signed them. Public and private keys differ in distinct ways, as seen in the table below.

Algorithm 

There must be two distinct keys for encryption and decryption in public-key encryption. The private key is only accessible to the owner, whereas the public key is accessible to anyone. In symmetric key cryptography, only one key is required for transmission between the two parties involved. The same private key is used to encrypt and decrypt the data. It is shared by the sender and receiver of an encrypted message.

Encryption and Decryption

The user’s public key is used to encrypt the content, which can only be decrypted with the user’s private key. That is the only way to receive the message.

Speed

The private key mechanism is significantly faster than the public key mechanism. This is due to the fact that a private key only requires one key, whereas a public key requires two keys.

Confidentiality

The private key is kept private and is not shared with anyone other than the wallet’s owner. When the private key is lost, it is impossible to recover it, and the encrypted file becomes unusable. These keys are typically difficult to remember because they involve complex numbering. However, the security of private keys is entirely up to the owner. That is why an offline storage device is the best way to keep your private keys safe. The public key, on the other hand, is accessible to all users and should be searchable. The public key is unlikely to be lost.

Authorization

The user’s private key can be used to digitally sign the web content, and the user’s public key can be used to verify it. This makes it simple to identify the message sender in the network and confirm that a message was sent by a trusted identity.

Bottom line

Data storage and security are becoming increasingly important as we move towards a digitized world. Because nobody knows the private key paired with the open public key, public key encryption allows users to maintain reasonable security practices. It’s useful for avoiding potential interceptions and cyber fraud. All you need to do is make sure your private key is secure and inaccessible to others.

After learning about the significance of private and public key in blockchain, I hope you now understand how the two terms differ.

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