What is a digital signature?

Our signature is our unique identifier. For years and years, the autograph was the ultimate prize for anyone looking for a personal memory from a celebrity. A quick look at a famous person’s Wikipedia page will often show you their signature on the right-hand side. Can you guess who these belong to? Answers at the bottom:

Digital signature

Digital signature

In the digital era, you might think there’s little need for the signature. With laptops and mobiles arguably becoming more common than pen and paper, where is the place for this old-fashioned identification method? Actually, they’re now a very important security tool in cyberspace.

A digital signature is a mathematical tool for protecting information. They provide an extra layer of security to an electronic message. They come in three parts:

  • A key generation algorithm – this selects a “private key”, which is used alongside a “public key”
  • A “signing” algorithm which, with a message and a key, creates a signature
  • A final algorithm which verifies whether the message, public key and signature are authentic

In the virtual world, a digital signature is akin to a seal. They’re far more difficult to forge or copy than the handwritten type. They also come with a mechanism to ensure the “signer” cannot deny that they “signed” the message.

Overall, digital signatures can be vital tools for distinguishing a legitimate user from an impostor and for confirming a contractual agreement conducted over email.

What do you think of digital signatures? Got any more questions? Tweet us at @justaskgemalto or by posting a comment below.

The signatures belong to Barack Obama and George W. Bush