Encryption was (and in some countries, still legally is) considered dual use technology. You needed to go through paperwork and licensing to export cryptography

Encryption was (and in some countries, still legally is) considered dual use technology. You needed to go through paperwork and licensing to export cryptography across the border. Symmetric keys longer than 64 bits were considered too strong. This led to all kinds of stupidity. Internet Explorer shipped with nerfed TLS capabilities, limiting key sizes to 40 bits or 56 bits depending on the version. When the encryption laws changed in 2000, Microsoft allowed users to download an update to improve SSL encryption: https://learn.microsoft.com/en-us/previous-versions/tn-archive/cc722908(v=technet.10)?redirectedfrom=MSDN https://learn.microsoft.com/en-us/previous-versions/tn-archi... You could legally encrypt emails, of course, as long as you kept the key sizes small and didn't export the encryption software to another country. If you sell and export encryption products from the USA (and a bunch of other countries, see the Wassenaar Accords) to certain places (including China and Russia), you're still obligated to register your product if you use modern key sizes. I'm not sure if governments still care now that OpenSSL and PGP are freely available to anyone, but if your proprietary email encryption program is found on North Korean computers, your government may ask you some uncomfortable questions.