This far we've talked about data confidentiality.
This is the most relevant aspect.
And the first thing that springs to mind when data protection is concerned.
But this doesn't always have to be the case.
Sometimes the integrity of data is equally important.
Data integrity refers to a situation when a given message has not been modified by an unauthorized person.
Data integrity can be maintained by adding specific checksums to the data this method also helps protecting
the integrity of operating system files.
If a document you open has a different check sum than that of a document saved by a trusted user.
This points to data integrity corruption.
Why is integrity so important.
Let's use online orders as an example.
If someone has spired that we've ordered five books.
This usually doesn't bother us but if that person modifies the order value from 5 to 500 books we would
be less than happy integrity is a vital feature of information.
Data authenticity is another key aspect to data security
authenticity is a bit broader in scope than integrity.
Authenticity is a feature of information that ensures that the sender of the data stream is legitimate.
And that the data has not been modified after it was sent by a trusted sender
This feature can be verified through the use of digital signatures will cover this incoming module's
as we stressed before.
You should not put too much faith in technology.
You can see an example of why limited trust is the best option.
It's a certificate for signing crucial information contained in system files or X Files.
It was stolen and used to sign malicious software authenticity is verified through digital signatures
on files that are usually generated from certificates
certificate has an assigned level of trust.
A user can give
the less feature of information is its availability
data availability is specified in an SLA service level agreement I.T. departments and business customers
are bound with the terms and conditions of an SLA.
The specifications of this contract define the maximum tolerable length of service unavailability and
determine the amounts of information that can be lost after a disaster.
You can find lots of information on soldiers on the Internet.
The key elements of the agreement are recovery time objective or T-O which is the duration of time in
which a service can be unavailable.
Most often calculated in a percentage the closer to 100 percent.
The longer the information needs to be available recovery point objective RPO which is the amount of
data that can be lost in the event of a failure.
The recovery time objective forms the foundation of all s.l AES.
The measures the non-negotiable duration of time within which information or services can be unavailable.
It is usually expressed as a number of Neyens if a given service is to be provided 365 days a year 24
hours a day seven days a week.
This means that an RTL value that has five nines ninety nine point nine nine nine percent can only be
shut down for whatever reason maintenance attacks threats.
For five minutes in a year
agreeing on a five nines article means that a given service or information has to be protected in a
special way.
It's impossible to provide an RTL this high if data is stored in one system only
hosting companies usually agreed to a four digit are.
Under the same assumptions 3:09 mean that a service can shut down for 8 hours per year maximum.
You can't expect your only computer to be set up for the whole year without interruption.
And 8 hours will probably be too little to successfully deal with an attack or to restore a system after
a failure.
Another part of an SLA which is defined in all contracts of this type is a recovery point objective
which is the measure that determines the amount of data that can be lost after an attack.
It's easier to ensure a recovery point objective of 0 percent.
It's a matter of replicating data and creating backups then to ensure and RTU equaling ninety nine point
ninety nine percent in the case of the RTU.
I have saleability comes with the need for investing in expensive equipment
ASL is are becoming increasingly popular and it's quite possible that you'll often be asked to sign
an SLA that determines the RPO as a 0 percent
businesses need to guarantee that whatever happens no data will be lost from the system.
We have few technologies that can ensure implementing good values of RTU and RPO will mention them later
on in the next modules of this course.
High availability of services usually require the use of specialist technologies.
There will also be covered in the next part of this course.
Thank you.