rjaWebsWhat PGP is
PGP — short for Pretty Good Privacy — is a method for signing and encrypting digital information, created by Phil Zimmermann in 1991. It is now maintained as an open standard called OpenPGP, and its best-known free implementation is GnuPG (often shortened to GPG). At its heart sits a pair of keys: a private key its owner guards closely, and a matching public key they can share with anyone. The two are mathematically linked, so anything signed with the private key can be checked by anyone holding the public one — but the private key can't be worked out from the public one.
Signing versus encrypting
PGP does two related jobs, and it's worth keeping them apart. Encryption scrambles a message so only the intended recipient can read it. Signing does something almost opposite in spirit: it leaves the content perfectly readable but attaches a tamper-evident seal proving who created it and that not a single character has changed since. For the web, signing is the everyday workhorse. When an open-source project ships a new release, a PGP signature lets anyone confirm the download is the genuine article and not a poisoned copy slipped in by an attacker. The same applies to source code: individual commits and version tags can be PGP-signed, and platforms such as GitHub show a "Verified" badge once they've checked the signature.
Trust without a middleman
PGP also introduced a distinctive idea called the web of trust. Rather than leaning on a single central authority to vouch for who owns which key, people sign one another's keys to say, in effect, "I've confirmed this key really belongs to this person." Trust is built from the ground up through real relationships, instead of being handed down from one company. It's a different philosophy from the certificate system behind the padlock in your browser — more grassroots, harder to quietly subvert — and its staying power is a big part of why PGP is still in daily use decades after it appeared.
Why provenance matters for your project
For a business owner the point isn't the mathematics — it's the assurance. Signed work is work you can verify rather than simply trust: proof of who produced it, and proof that it hasn't been altered on the way to you. As tampering with software downloads and code supply chains has become a favourite line of attack, the ability to check a signature rather than take one on faith is a small, quiet habit that says a great deal about how seriously a shop takes its craft.