WHAT IS IMMUTABILITY?
Immutable means that something is unchanging over time or unable to be changed.
So in our context, it means once data has been written to a blockchain no one, not even a system administrator, can change it. This provides benefits for audit. As a provider of data you can prove that your data hasn’t been altered, and as a recipient of data you can be sure that the data hasn’t been altered. These benefits are useful for databases of financial transactions.
Immutability is relative. For example if I send an email to a large list of friends, that data is pretty immutable from my perspective. To change it, I’d have to persuade my friends each to delete the email (or persuade Gmail and the people running all the mailservers of my friends). From my perspective, and with the control I have, that email is immutable – I can’t unsend or revoke it without collaboration and risk of detection.
So immutability is relative, and relates to how hard something is to change.
eos
