Public keys, secret keys & digital signature

All these are forms of cryptography. Public-key cryptography is an encryption scheme where mathematically related keys that are not identical are used. Each key has a function. The public key encrypts and the private key decrypts.

The secret keys are usually in the possession of one person privy to certain information. Only they can open the packages of data meant for them.

With cryptography, the security in a blockchain remains tight. Public keys can be freely shared but only the intended receivers of the digital assets have the private keys that can decrypt the information and create digital signatures.

Speaking of digital signatures, they are cryptographic values that we calculate from data and the secret key belongs to the owner. Only they can open this message. They know which message to open and which one is intended for them because of the digital signature that is uniquely theirs.