Digital signature how does it work

Generally, the contents of the document to be signed digitally is hashed and encrypted. Changing any part of the document completely changes the hash. Public key cryptography: Also known as asymmetric encryption, this cryptographic method uses both public and private keys to ensure safe delivery of the contents of a document from the party requesting a signature to the other party providing the signature.

Once the digital message is encrypted by a public key, only an individual with the corresponding private key can decrypt that data.

Public Key Infrastructure PKI : In simple terms, it is an aggregation of the people, standards, policies and systems that back public key distribution and validation of identity using certificate authority and digital certificates. Certificate Authority CA : Usually a third party, a certificate authority is responsible for validating the identity of a person. To do this, it generates a pair of public and private keys, both of which are used to verify the identity of the signer and the recipient.

The CA then issues a digital certificate they signed once they have been able to establish the identity of the signers. They also contain the public key and other important information about the individual, organization and CA.

Essentially, users give other users a vote of trust by signing certificates of people with identities that are verifiable. Digitally signing a document is dependent on the standard format called PKI. Using this PKI, a digital signature provider generates a public and private key pair.

The contents of the document to be signed is hashed and encrypted using the private key. This key should be kept securely by the signer. Once an individual signs a document, a hash value is produced. The signer then gives the recipient access to the public key to decrypt the contents of the message, a process that creates another hash value. If this hash value does not match or correspond with the hash value from the signer, the document would not open.

If it does, the document opens and the recipient can sign. The function of the CA is to verify that the signer is who they claim to be. The public key can be sent to the CA along with details of the signer to carry out this verification.

To help the recipient know that the signer is who they claim they are, the signer can send along with the document, a copy of the full certificate. Should the recipient trust what is issued by the CA, they can go ahead to sign the document. Essentially, the CA vouches for the signer, establishing that they are who they say are.

Digital signatures are more convenient, boost efficiency, encourage remote work collaboration and are an asset where security is of the essence.

This article gives a detailed brief of what they are and how they work. Co-founder of CocoSign, Caroline Lee is an entrepreneur with interests in marketing, business management, remote work and trends. Albert Santalo. Steve Taplin. Shrabona Ghosh. The certificate is used to confirm that the public key belongs to the specific organization.

The CA acts as the guarantor. Digital certificates must be issued by a trusted authority and are only valid for a specified time. They are required in order to create a digital signature. Skip to main content Celebrating our one million customers. Sales Solutions Back. Customer Success We'll implement the cloud for you Learn More.

Explore Customer Stories. Partners Partner Program Partner Login. Developers Back. Pricing Back. Understanding digital signatures What is a digital signature, and how can you create one?

Free Trial. What are digital signatures? Want to know more about our Standards-Based Signatures? Digital Signatures. Need to talk to someone or have more than 10 users? Contact Sales. Want to try DocuSign for free? Get your free day trial. Free trial. How do I create a digital signature? What is a Certificate Authority CA? Why would I use a digital signature? Digital Signatures. A more secure way to authenticate a signature Digital signing is now used as an accepted means for producing signatures that are considered legally binding in many countries, including members of the European Union EU , Saudi Arabia and the United States.

The process of digital signing There are typically three algorithms involved with the digital signature process: Key generation — This algorithm provides a private key along with its corresponding public key. Signing — This algorithm produces a signature upon receiving a private key and the message that is being signed. Verification — This algorithm checks for the authenticity of the message by verifying it along with the signature and public key.

By applying asymmetric cryptography methods, the digital signature process works to prevent several common attacks where the attacker attempts to gain access through the following attack methods: Key-only — Attacker has access to the public key Known message — Attacker has access to valid signatures for known messages, but not those that they have chosen Adaptive chosen message — Attacker gains access to signatures on various messages that they have chosen Reasons to consider implementing the digital signature process Aside from facilitating business processes and preventing the forgery of critical messages and documents, the use of digital signing provides additional validation benefits.

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