In my opinion? A great company culture that makes people happy, inspires loyalty and pride, and curates a sense of shared ownership of the secret information. Security through locks and password keys is great, but someone, or rather in the case of a company, a whole lot of people, are going to need access to secure information in order to do their jobs. It's not hard to save the information. It's even less hard to anonymously leak that information online once it's been taken. A lot of organizations can keep secrets extremely well not because t watch the people with the information but because those people have no desire to reveal the information in the first place. At any point where someone might reveal information, a mini decision is made by them about whether it would be more profitable to keep that information or to reveal it. Make it so that it's always going to be better to keep the information secret. Secrets are conveniently self-keeping if t're in the correct environment. Secrecy breeds a culture of exclusivity, and when the secret is revealed, the secret-keeper's "power capital" goes down. In many ways, it's in the secret-holder's interest to not reveal the information in the first place because if t do, t hold less power by being part of a less exclusive group. Thanks for the Protectpdfonline !
A lot of this functionality is built into the open-source GPG suite, and you can use it to encrypt files from any OS without installing any software. GPG is built-in or downloadable to pretty much every office suite.