Security assumptions of public-key cryptography

Public key cryptography is a way to secure information by using a pair of keys: a public key and a private key. The public key is used to encrypt data, while the private key is used to decrypt it.

However, there are a few threats to the security of public key cryptography in the Blockchain. One threat is poor random number generation, which can make the encryption vulnerable to attacks. Another threat is the failure to properly protect private keys from being lost or stolen. If someone gets hold of a private key, they can access and manipulate the encrypted data.

In addition, the future development of quantum computers poses a long-term threat to the security of public key cryptography. Quantum computers have the potential to break the encryption algorithms used in public key cryptography, making the Blockchain vulnerable to attacks.

Overall, it's important to be aware of these threats and take measures to ensure the security of public key cryptography in the Blockchain.

Poor random number generation

A private key is a large random number that is used to generate a public key, which is then used to access a blockchain account. If someone can guess your public key, they can control your account and do things like sign transactions on your behalf or create fake blocks in the blockchain network.

One way that private keys can be compromised is through poor random number generation. Some blockchain wallet algorithms use weak random number generation algorithms, like using the current time on the system clock as a seed. This is not good for cryptographic random number generation because the system clock times are relatively constrained and can be easily guessed. This makes it easier for someone to guess a private key and gain control over a blockchain account.

There was a case where a thief, known as the blockchain bandit, took advantage of weak keys and stole value from over 700 different accounts. The thief identified the weak keys by scanning the blockchain for public keys associated with them. Once they found a weak key, they transferred the value in that account to their own account, where only they knew the private key.

It's important to properly protect authentication information for a blockchain account because once something happens, it can't be undone. In a decentralized system like blockchain, there's no one to appeal to or reverse transactions like you can with banks or credit card fraud. So it's crucial to use strong random number generation algorithms and keep private keys secure to prevent unauthorized access to blockchain accounts.

Lost/stolen private keys

A private key is like a password that allows someone to access their Blockchain account. However, even if someone creates a strong private key, it can still be lost or stolen. There have been cases where people accidentally threw away a hard drive containing their private key, or where attackers tricked someone into giving them their private key.

There are different ways that private keys can be stolen. For example, attackers can pretend to be operators of cryptocurrency exchanges and convince people to send them their private key. They can also take control of someone's phone number and use it to reset the password on their cryptocurrency exchange account. There is also malware that can steal private keys from a user's computer or change the target address when copying and pasting a private key.

Once an attacker has a private key, they can use it to access the person's Blockchain account and steal their cryptocurrency. The security of public key cryptography, which is used in Blockchain, relies on the assumption that only the legitimate owner knows the private key.