A magstripe is literally just a flat strip of magnetic tape, like an audio cassette. Devices like Square Reader just encode the magstripe as audio into an iPhon

A magstripe is literally just a flat strip of magnetic tape, like an audio cassette. Devices like Square Reader just encode the magstripe as audio into an iPhone's mic input. You could save that to a Voice Memo, stick the playhead from a RadioShack 3.5mm/cassette adapter in a reader, and press play. Can't find it, but I've seen a demonstration on YouTube of someone doing this to enter their apartment building. The TV show White Collar's pilot has a cool depiction of Neil Caffrey copying a guard's magnetic stripe badge using a tape deck by recording it to tape, then playing it back through the record (write) head on the other side of the tape player while he slid a new card through. It would be hard to get the timing right, but there's no reason this shouldn't work. It's incredibly primitive technology, as is simple RFID - the cloning process isn't much more difficult. Fortunately my university uses HID iCLASS contactless smart cards - there is actually a cryptographic handshake between the reader and my student ID which is resistant to replay attacks. If implemented correctly, it's impossible to copy the electronic access control portion of a student ID without the university's private keys. (The same access control infrastructure that's on my dorm's main entrance also guards healthcare information, nuclear and virology labs, etc. so that makes sense.)