Public Key

tl;dr: A public key is a cryptographic key used in public-key cryptography, which enables secure communication between two parties by using a pair of keys. In public-key cryptography, there are two keys: the public key and the private key. The public key is used to encrypt messages, while the private key is used to decrypt them. Public-key cryptography and public keys are widely used in modern communication systems and are critical for secure communication and transactions over unsecured networks like the Internet. In the context of cryptocurrency, a public key is a unique identifier used as an address to receive cryptocurrency transactions, such as a Bitcoin address.


What Is a Public Key?

A public key is a part of a public-key cryptography system that uses a pair of keys to enable secure communication between two parties. It is a cryptographic key that can be freely shared and distributed to anyone who wishes to communicate with the owner of the key.

In public-key cryptography, there are two keys: the public key and the private key. The public key is used to encrypt messages, while the private key is used to decrypt them. When someone wants to send a message to the owner of a public key, they use the key to encrypt the message, and only the owner of the corresponding private key can decrypt and read the message.

Public-key cryptography is widely used in modern communication systems, such as secure email, online banking, and e-commerce, as it provides a secure and efficient way to transmit sensitive information over an unsecured network like the Internet. The most common public-key algorithms used in cryptography are RSA, Diffie–Hellman key exchange, and Elliptic Curve Cryptography (ECC).

Public Key in the Context of Cryptocurrency

In the context of cryptocurrency, a public key is a unique identifier that is used as an address to receive cryptocurrency transactions. It is a long string of alphanumeric characters that is generated from a corresponding private key using a cryptographic algorithm.

For example, in the case of Bitcoin, a public key is typically represented as a Bitcoin address, which starts with the number "1", "3", or "bc1" and is a string of letters and numbers, like this:

1GinkuKexAZM8FzxUQGBz6YCuaRfkE8ofi

When someone wants to send Bitcoin to another person, they use the recipient's public key (Bitcoin address) as the destination address for the transaction. The Bitcoin network uses this address to verify the transaction and transfer the cryptocurrency to the recipient's account.

Public keys are used in combination with digital signatures to ensure the security and authenticity of transactions. When a transaction is initiated, it is signed with the sender's private key, and the digital signature is verified using the sender's public key. This helps to ensure that the transaction is valid and has not been tampered with by anyone else.

In summary, a public key in the context of cryptocurrency is a unique address used to receive cryptocurrency transactions, such as a Bitcoin address. It is used together with digital signatures to ensure the security and authenticity of transactions.