Views Block's machine name is being "hashed" (?)
This is because the block module expects a 'delta' (block id) up to 32 characters long. But a view block display can have up to 65 characters: up to 32 characters from the view name and 32 characters from the display name and an hyphen '-' between them.

When the delta exceeds the 32 characters limit, Views will hash it through md5 — it is not a random string. You can safely use it for CSS and jQuery selectors.