Digital Signatures: Ensuring Security in Blockchain

Digital Signature is a method of authenticating a digital message.

What is Digital Signature?

Digital signatures use cryptography to determine the authenticity of a digital message or document. When a signature is deemed valid, it assumes that the message came from the person from whom it came (called authentication), the sender cannot reasonably deny that the message came from him (non-repudiation), and that the message has not been altered or tampered with (integrity).

Public key cryptography, which uses public and private key pairs for encryption and decryption, is used in the creation of digital signatures. Public keys, as the name implies, are publicly transmitted, while private keys are kept secret.

To digitally sign a message, the sender uses software to create a hash of the message, which is then encrypted with the private key. To validate the message, the encrypted hash is decrypted with the sender’s public key. A second hash of the message is created; if this hash matches the decrypted one, the message is valid.

Digital signature is not the same as electronic signature, even though the former term is often used to describe the latter technology. The term "electronic signature" refers to any digital sign that is intended to represent a signature. Common examples are HelloSign and Adobe Sign.

That said, some electronic signature tools may include digital signature technology, which involves the use of a public key cryptography element.

The use of digital signatures is common on the Internet, for example, for authenticating network connections. They are also becoming increasingly common in government agencies. For example, key documents are now published by the U.S. Government Printing Office with accompanying digital signatures to verify their authenticity.