Digital signatures, like handwritten signatures, are unique to each signer. Digital signature solution providers follow a specific protocol, called PKI.
PKI requires the provider to use a mathematical algorithm to generate two long numbers, called keys. One key is public, and one key is private.
When a signer electronically signs a document, the signature is created using the signer’s private key, which is always securely kept by the signer. The mathematical algorithm acts as a cipher, creating data matching the signed document, called a hash, and encrypting that data. The resulting encrypted data is the digital signature. The signature is also marked with the time that the document was signed. If the document changes after signing, the digital signature is invalidated.
As an example, Alice signs an agreement to sell a timeshare using her private key. Bob receives the document. Bob also receives a copy of Alice’s public key. If the public key can’t decrypt the signature (via the cipher from which the keys were created), it means the signature isn’t Alice’s or has been changed since it was signed. The signature is then considered invalid.


Practice:
1. Open https://andersbrownworth.com/blockchain/public-private-keys/keys
2. Use the following keys:
3. Verify the signature of this message:

Use the same algorithm to sign blockchain transactions.