Cyber Security

What is the purpose for this choice?
If it is for learning, I would say NO, as internet has plenty of resources for you to learn and develop skills in is.
If its for a job and consequently shifting to Ireland, which many Asians dream of, then I wouldn't really suggest unless someone is sponsoring your course and stay. Getting a job in UK or EU is next to difficult owing to stringent laws around the Visa being provided. In order to employ you , guys out there will need to flush out a huge amount of money to the government. So ensure you have gpod knowledge about what is thr job market out there.
DCU is gooduniversity.ITsector in dublin is good. But I would suggest try to search for job opportunities in the field which you want to do masters. Cyber security is really limited skill in current IT industry but just check if there are jobs in Ireland in that field. Those kind of skills require years of experience and if you don't have relevant experience then it will be hard to get job in that field.Check on Linkedin, Glassdoor, Irishjobs, Indeed, Monster, etc. Lets say if there are only few jobs then you should decide whether i should go or not.

Yes, why not.
End of the day, interest in specific field matters. ECE students understand the hardware which becomes a + point for a cyber background. Start by learning the basics of networks and network security. Certifications like CCNA Security, Network + will help you to understand the basics. Once you are done with this then learn scripting basics if interested and get hands-on with Linux/Windows OS as much as you can. With this knowledge you will be able to study and get certified as a CEH (Certified Ethical Hacker). Cyber Security is a very vast term and there are so many avenues within that you can master and make it your expertise.