On the other hand, leaving the length of the original text unchanged can leak information. Imagine a person's full name is redacted but it's only 7 characters l

On the other hand, leaving the length of the original text unchanged can leak information. Imagine a person's full name is redacted but it's only 7 characters long in total. That massively cuts down on the possibilities and may be enough to unmask their identity if there are only a few thousand names that might plausibly be listed.