How are MongoDB's ObjectIds generated?

Question

Are they somewhat random? I mean....would people be able to break them apart?

Accepted Answer

Generation

They are usually generated on the client side by the driver itself. For example, in ruby, BSON::ObjectID can be used:

- https://github.com/mongodb/bson-ruby/blob/master/lib/bson/object_id.rb#L369

You can also generate your own ObjectIds. This is particularly useful if you want to use business identifiers.

Breakability

- When using driver generated ObjectIds, is low

- When using own business Id, is slightly higher depending on their predictability (login, consecutives identifiers...)

Solution