At 12:25 PM 8/9/93 -0700, Timothy C. May wrote:

despite the talk of mandatory "trap doors" in encryption systems, encryption is fundamentally easy to do and hard to detect. (For those who doubt this, let me describe a simple system I posted to sci.crypt several years ago. An ordinary digital audio tape (DAT) carries more than a gigabyte of data. This means that thhe least significant bit (LSB) of an audio DAT recordingng carries about 8megabytes of data! So Alice is stopped by the Data Police. They ask if she's carrying illegal data. She smiles inocently and say "No. I know you'll search me." They find her Sony DATman and ask about her collection of tapes and live recordings. Alice is carrying 80 MB of data---about 3 entire days worth of Usenet feeds!---on each and every tape. The data are stored in the LSBs, completely indistinguishable from microphone and quantization noise...unless you know the key. Similar methods allow data to be undetectably packed into LSBs of the PICT and GIF pictures now flooding the Net, into sampled sounds, and even into messages like this...

Alice better not be carrying any software that could retrieve that data. The cynic in me suggests that this scenario is just an excuse for the data police to seize any equipment or data it feels like. Besides, Alice won't be stopped by the data police, Alice will have her door kicked in by the data police and they'll take everything electronic she has, including harmless music and video. And anything electronic they find in her residence, whether it belongs to her or not.