Overview[]
An Electronic Copyright Management System (ECMS) is a scheme to make digital works harder to copy and easier to license. Some of these schemes emphasize the technology of making works “harder to copy”; others emphasize ways of making it “easier to pay for copying.” Commonly both elements are present, so the emphasis is a matter of degree.
The most basic systems rely on “secure transmission” of digital materials between sender and recipient. Invariably, over the Internet, this is done by means of encryption. For copyright owners’ purposes, simple, single-key encryption alone provides some, but not much, protection. It can prevent a “thief” stationed at an intermediate computer from gaining access to the material, for the material will be gibberish without the necessary decoding key. The authorized recipient of the material can be required to make a payment to the owner before obtaining the key. Once the key is obtained, the recipient can decrypt the material and make use of it. Nothing in the scheme itself, however, prevents the recipient from further circulating either the key (if the owner uses the same key for all encryption), or the decrypted material itself without authority.
For some works, that modest limitation may be more than enough. Many copyrighted materials are short in length and have a short “half-life.” A timely newspaper column on a current event, for example, may not have substantial monetary value even when first released, and certainly not as time goes by and the news becomes stale. Thus a mechanism based on encryption that ensures a small payment in exchange for timely access may be all the copyright owner desires. Further, unauthorized recirculation may be limited by nothing more than the little time and trouble it requires, relative to the modest value of the work.
A stronger degree of protection can be created with a centralized source of access to copyrighted material. At one level, this is no more than what many online database suppliers like Westlaw and Lexis offer: the material itself is not “sold” or distributed; rather “access” to the information is sold. The user must enter a contractual relationship with the seller; passwords are issued to authorized users only; the entire database is either too big or is technically restricted in such a way that an authorized user cannot obtain more than a small portion of it at any one time.
But more sophisticated variations are possible. For example, a user might gain access to an entire lengthy work like a novel or movie, but the access is only for purposes of making use of the work while “connected” to the source site. That limitation might be enforced by having the novel or movie kept on the source and sent down in bits as it is being read or viewed; or it might be enforced by downloading the whole thing to the user, but encrypted in such a way that only when and only while an authorized user is connected to the source site will the material be decrypted. Upon disconnection, the material is left in an encrypted state.
Some variations of this scheme are designed to be accomplished with special purpose hardware and software. Others rely on software alone, coupled with Web browser software. Generally the software approaches involve the creation of a two-part “package,” consisting of the actual copyrighted content, along with a set of instructions or terms for gaining access to that content. These “packages” are sometimes called “containers” or “digital containers” or “digital objects.”