An Interactive Art Installation by:
Peter Broadwell
Rob Myers
With lots of help from:
Delle Maxwell
Rebecca Fuson

August 1998 -
It used to be that most interactions between people took place face to face. With a desire to keep something confidential, two people could wander into a field away from listening ears. Modern society has developed many technologies that alter this traditional manner of communication. Some of these endeavor to preserve the confidentiality of old. Unfortunately the government of the USA has decided that technologies enabling secure communication are a threat to its power and need to be controlled. The government would like to be able to eavesdrop on all communication and understand what they might hear.

We think this is wrong!

The government's case seems to center around stopping terrorist activity and kidnapping. These are not frivolous concerns -- however, ordinary people's rights are being trampled in the process. Once personal  privacy slips away, it never seems to come back. Is this what we really want in the long term?

Plasm: not a crime explores the artistic point of view that it is not a crime to share a secret with a friend. *

Earlier this year we submitted a concept video of this piece to the Ars Electronic 98 electronic arts festival. This festival takes place every year, focusing on a different theme related to art and technology. This year's theme was INFOWAR; our piece seemed like a good fit. Indeed the festival's jury thought so as well - we won an award (essentially second place in the Interactive Art Category) and feel quite honored.

The piece was inspired by a recent publication by Ron Rivest.  His paper, Chaffing and Winnowing, describes a technical way to provide secure communications without encryption. We applied his technique in a publicly accessible demonstration which allows people to share sensitive/intimate communications.

The methodology begins by dividing the communication into a large number of small pieces. Each of these pieces is then combined with a secret identifier, and the combination is authenticated with a crytographically secure hash function. For this we are using the Tiger hash function, recently published by Ross Anderson and Eli Biham. The results of the hash function, the original unencrypted data  and that data's position in the original communication are combined to form a chunk. These chunks are mixed up and merged into a growing pool; as more and more new messages are added to the pool, it becomes increasingly difficult to determine which pieces belong to the same message. However, with the appropriate secret identifier in hand, you can check the signature on each piece and only use the ones which belong.

We have visualized this process using 3D computer graphics. The pool of data appears as a continuous swirl of unrecognizable chaff flowing graphically across networked viewing stations.

In the festival setting, participants are free to create their own personal messages out of anything that can be put under a video camera. Each new message captured generates its own secret identifier. These secrets serve as the key to both sign and retrieve the content. They also become an item of info-exchange. We facilitate this role by printing our secret identifiers as graphical badges,  encouraging viewers to wear them out in the open, trade them with fellow festival attendees, and sport them as cryptographic adornment.

Each viewing station employs the SGI O2's built in video capture to read the secret identifiers printed on the viewers badge. These identifiers are converted into a form useable by  the Tiger hash code and are subsequently used to winnow out the corresponding message. The original image gradually reappears on the screen as each matching piece of chaff sticks into its proper place.

We would like to encourage visitors to form their own meaningful, personal messages within this framework. To offer inspiration, we will stock a  library of thematic, provocative, collageable images. Some of these will be gathered from books that have historically been in the crossfire of freedom of speech. Others will be inspired by what you suggest here:

What are some categories of things you think should be private!
View what others have contributed

We would like to offer the code used in this piece on our web site. Unfortunately,  the US government could then accuse us of exporting "secure communication technology," a felonious offense. Perhaps the laws will change and we can share this code among all interested folks.

Even to take the piece to the festival might have been breaking the law - we chose to get an expedited determination from the Bureau of Export Administration. James A Lewis, Director, Strategic Trade and Foreign Policy Controls Division, granted that we could use the License Exception TMP to legally participate in the show. We thank Cindy Cohn of McGlashan & Sarrail for helping us navigate through this process.
* The Plasm: series of interactive art works focuses on giving life to better human/computer relationships. The name derives from protoplasm - the building block for all life.