Antonopoulos, A. (2015): Mastering Bitcoin Unlocking Digital Cryptocurrencies
Compared to symmetric cryptography, asymmetric cryptography (or public key cryptography) is a cryptography method with two different keys for sender and receiver instead of only one key. This method is used, for example, for Bitcoin. The most popular methods are RSA and ECDSA.
Each participant receives a public and a private key in the case of asymmetric cryptography. The public key serves as an address and can be viewed by everyone. The private key is only known to the owner and should be kept in a protected place, as it serves as a signature.
If sender A executes a transaction and encrypts it with A's private key, all participants can use A's public key to verify that this transaction was actually executed by A. This is possible because of the encryption with a hash function, which is a one-way function . Privacy and validation can thus be guaranteed without a central authority in the Blockchain.