a public key is a large numerical value that is used to encrypt data In cryptography. The key can be generated by a software program, but it is more commonly provided by a trusted, designated authority and made available to all via a publicly accessible repository or directory. Scroll down for more details on how public keys work for cryptocurrencies.
What is a Public Key?
The public key is a one-of-a-kind personal address that is shared by all blockchain participants. It is a piece of cryptographic code that enables users to receive cryptocurrency into their accounts. The tools required to ensure the security of the crypto economy are the public key and the private key.
Unreadable messages are converted into unreadable formats by encrypting them with a public key, which is a cryptographic code generated by asymmetric-key encryption techniques.
Because the Bitcoin public key is such a long string of digits, it is compressed and truncated in the Bitcoin protocol to generate the public address. If the owner’s public key is lost or misplaced, the private key can be used to recreate it.
A public key can also be used to encrypt a message or validate a digital signature. It comes with a corresponding private key that is only known to the owner. Private keys are used to decrypt messages encrypted with the corresponding public key or to sign documents. In other words, a public key prevents unauthorized access to data, while a private key is used to unlock it.
A certificate authority, which issues digital certificates that prove the owner’s identity and contain the owner’s public key, provides public keys. An asymmetric algorithm is used to generate public keys, which pair the public key with an associated private key. The most common algorithms used to generate public keys are Rivest-Shamir-Adleman, elliptic curve cryptography, and Digital Signature Algorithm.
How Public Keys Works
A cryptographic key is a mathematical algorithm used to encrypt or decrypt data that is implemented in software or hardware. It is a sequence of bits that is combined with data to form ciphertext. The cryptographic key can also be used to decrypt data and restore it to plaintext.
There are two kinds of cryptographic algorithms: symmetric and asymmetric. Symmetric key algorithms encrypt and decrypt information using a single key, whereas asymmetric cryptography uses two keys: a public key to encrypt messages and a private key to decode them.
The process for sending and receiving data via asymmetric cryptography typically consists of five steps:
- Key generation. Each individual generates a public and private key.
- Key exchange. The sender and recipient exchange public keys.
- Encryption. The sender’s data is encrypted using the recipient’s public key.
- Sending encrypted data. The encrypted data is sent to the recipient.
- Decryption. The recipient decrypts the message using their own private key.
Public Key cryptography
The term “cryptography” has Greek roots and was originally intended to be a means of secret communication. Cryptography evolved from the authoring and decoding of classified messages by intelligence agencies and the military to become its own discipline of computer science. The origins of cryptocurrencies, like the internet, can be traced back to academic and military applications, which then spread to the commercial sector as the technology gained popularity.
Public-key cryptography (PKC) can be used to confirm the authenticity of data by utilizing asymmetric encryption. PKC was designed primarily for message encryption and decryption. Cryptocurrencies are now using this technology to encrypt and decrypt transactions. Without PKC, cryptocurrencies would be unviable (PKC).
PKC heavily relies on trapdoor functions. These are one-way mathematical functions that are easy to solve one way but nearly impossible to solve the other. While it is possible to reverse engineer these functions, it would almost certainly necessitate the use of a supercomputer and thousands of years.
When a user makes their first Bitcoin or altcoin transaction, their digital wallet creates a one-of-a-kind combination of public and private keys. Each digital key is made up of a long string of alphanumeric letters that work together to protect a user’s assets.
Public Key Applications
A public key is primarily used to encrypt messages before sending them. Asymmetric encryption generates both the public and private keys at random. Anyone with access to a public key can encrypt data, but only someone with the matching private key can decrypt the data.
Because the public and private keys are mathematically linked, they are used in tandem to encrypt and decrypt data. The information will be unreadable if anyone other than the owner of the private key attempts to decrypt it using the public key.
Public key encryption can also be used to create digital signatures. The digital signatures are generated via the following steps:
- The sender identifies the file to be digitally signed.
- The document application on the sender’s computer calculates a unique hash value for the contents of that file.
- The sender’s private key is used to encrypt the hash value, creating the digital signature.
- The original file and the digital signature are sent together to the recipient.
- The recipient uses the sender’s public key to decrypt the digital signature’s hash.
- The recipient’s computer calculates the hash of the original file and compares it with the decrypted hash. If the two hashes match, the signature is verified. If the hashes don’t match, that’s evidence that the document has been altered or that the signature isn’t valid.
Secure Socket Layer and Transport Layer Security connections
To establish a secure connection between the server and the client, SSL/TLS employs public key encryption.
This encryption method makes it possible to use Hypertext Transfer Protocol Secure. To establish the identities of both parties and to exchange a shared session key that enables a symmetric cipher, the communication session is first established using asymmetric encryption.
Because symmetric encryption, which uses a shared key, is faster and more efficient than asymmetric encryption, it makes sense to use it for as much communication as possible.
Public key risks
While public key encryption is more secure than symmetric encryption, there are a few risks to consider, including the following:
- Low-quality key. A poorly crafted asymmetric key algorithm — one that’s too short in length, for example — is a security risk.
- Lost private key. If the private key is lost or misplaced, access to the data becomes problematic.
- Man-in-the-middle (MitM) attacks. Public key encryption can be a target for MitM attacks. The two main ways of trusting the identity of a website are the site’s security certificate and its public key encryption. If either of these is compromised, a malicious party can insert itself into the connection between a user and a website and then capture any information sent between the two.
The cryptocurrency network is kept secure by employing complex mathematical functions to ensure that a private key cannot be deduced from the public key, particularly since the public key and its hash version are visible to everyone on the network.
Because it is impossible to regenerate the private key from the public key or address, if a user loses his private key, any bitcoin or altcoin stored at his public address will be inaccessible for the rest of his life. A user who loses his public key, on the other hand, can have it recreated using his private key.