cryptographically indicate effort

Traditionally, cryptographic signatures have been used to prove a connection between published information and the person that published it. This can also be an indication that the published information has some value because someone is willing to connect it to his name. However, sometimes it is useful to imply some value for information without connecting it to a single person, for example to publish it on behalf of a project or company. To provide a technical means for this, this service provides signatures for PGP keys not by assuring the key belongs to a certain person, but by assuring that some measurable effort has been put into the key. This is done by demanding a hash cash computation from the key owner.

To use it, send an e-mail to hash-cash-signing@quidecco.de with two lines in the body.The first line must consist of the string "key=" followed by the key id of the PGP key to be signed. The second line must consist of the string "bits=" followed by the number of fixed bits the hash cash challenge should demand. The e-mail body could look as follows, for example:

key=0123ABCD
bits=20

The key signing service will then send a response containing the instructions on how to fulfill the challenge.