Philip R. Zimmermann is the creator of Pretty Good Privacy (PGP), which he released in 1991 as free software for encrypting email and files. PGP combined public-key cryptography with conventional ciphers to give individuals, not just governments and large institutions, access to strong encryption. In his essay “Why I Wrote PGP,” first published in the 1991 PGP User’s Guide, he argued that “the only way to hold the line on privacy in the information age is strong cryptography” (https://philzimmermann.com/EN/essays/WhyIWrotePGP.html).
The essay lays out his motivation as a matter of civil liberty. Zimmermann saw electronic communication losing the everyday privacy that paper mail and face-to-face conversation once carried, and he pointed to government initiatives such as Senate Bill 266 and the later Clipper chip proposal as attempts to weaken or back-door civilian encryption. His widely quoted line captures the stance: “If privacy is outlawed, only outlaws will have privacy” (https://philzimmermann.com/EN/essays/WhyIWrotePGP.html).
Because PGP spread internationally soon after release, Zimmermann became the target of a US Customs criminal investigation focused on whether distributing strong cryptography violated export controls on “munitions.” The investigation ran for years before being dropped without charges, and it turned Zimmermann into a public symbol of the crypto wars. His own site collects his background, essays, and the history of PGP (https://philzimmermann.com/EN/background/index.html).
By the time he updated the essay in 1999, Zimmermann noted that export restrictions on cryptography had relaxed, which he treated as a hard-won victory for the privacy side of the debate.