# Key construction

200 puts of identical bytes -> 200 distinct ids (a content hash would give 1)
owner '../admin'             -> bad-owner: owner must match [a-z0-9][a-z0-9-]{0,31}
owner 'user-42/../../x'      -> bad-owner: owner must match [a-z0-9][a-z0-9-]{0,31}
owner 'USER'                 -> bad-owner: owner must match [a-z0-9][a-z0-9-]{0,31}
owner ''                     -> bad-owner: owner must match [a-z0-9][a-z0-9-]{0,31}
owner 'a b'                  -> bad-owner: owner must match [a-z0-9][a-z0-9-]{0,31}
owner 'user-42\0'            -> bad-owner: owner must match [a-z0-9][a-z0-9-]{0,31}
owner 'xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx' -> bad-owner: owner must match [a-z0-9][a-z0-9-]{0,31}
id    '../../etc/passwd'                 -> bad-id: an image id is 32 lowercase hex characters
id    'ABCDEF0123456789ABCDEF0123456789' -> bad-id: an image id is 32 lowercase hex characters
id    '0123'                             -> bad-id: an image id is 32 lowercase hex characters
id    '0123456789abcdef0123456789abcde/' -> bad-id: an image id is 32 lowercase hex characters
user-43 asks for user-42's id -> NoSuchKeyException (key is rebuilt under user-43/)
