Obtaining a Portal Key
When you hack a portal, about 75% of the time you will receive a key for that portal if you don’t already have one. (Note that portal keys are specific to the portal from which they are hacked; they aren’t interchangeable with keys from other portals.) If you already have one or more keys for a portal but want more, you can drop them or put them into a capsule before you hack. Alternately, you can use the MORE command glyph before a glyph hack.
If you don’t have a key for a portal and would rather not get one when you hack, you can long-press on the portal and select “Hack No Key,” or use the LESS command glyph before a glyph hack.
When links are destroyed, the portal keys used to create them are dropped at the origin portal. Look on the ground near the portal for small yellow objects and pick them up; those are portal keys that go to the remote portals.
If you wish to free up inventory space, portal keys can be transferred into a premium capsule called a key locker. They can only contain keys, but their contents don’t count against your inventory cap. Key lockers can be obtained from the store.