DIR2:CHK

[zooko]

Directories are currently stored in SSK files. They were designed so that directories could be easily stored in different types of files, so it shouldn't be hard for someone to implement DIR2:CHK files. These would have nice properties, especially for backup applications:

• It would be nice to know that your old backed-up directory is immutable.
• It would allow convergence of backed-up directories (note that front-end backup tools such as Brian's backupdb and Shawn's backup tool might figure this out and converge old directories for you, but doing it by converging CHK's on upload might work better for some cases, including the case that you aren't using backupdb or Shawn's tool).
• It would be faster to create (currently SSKs require an RSA key-pair generation on creation, which is expensive).