Information Assurance concerns itself with implementing measures focused at protection and safeguarding of critical information and relevant information systems by assuring the integrity, availability, authentication, confidentiality and non-repudiation. The measures also provides for restoring information systems after an attack by putting in place proper protection, detection and reaction abilities.
Information Security deals with protecting information and information systems from illegitimate access, usage, revelation, alteration, disruption and destruction to achieve the objectives of data integrity, availability and confidentiality.
Information Assurance is more strategy focused which implies that the emphasis is more on tactical deployment of security policies rather than building up of security infrastructures and designing of protective applications. Information Security, on the other hand is tools and tactics focused implying that the development of strategic security software and infrastructure is stressed upon to bolster the overall protection of information system.
Information Assurance specifies the ways to manage and protect critical information more effectively. Information Security, on the contrary deals with technology and operations to put together an effective mechanism to better plug the loopholes in the system. The stress is on risk management by adopting an adaptive and proactive approach in Information Assurance, whereas Information Security bothers about mitigating the risks involved by technically evolving architecture and systems to tackle system vulnerabilities.
Information Assurance is broad-based i.e. it is related to risk assessment and management on an organizational level such as conducting security audits, ensuring compliance to security policies etc. Information Security is concerned with strategic development and deployment of security applications and infrastructures like anti-virus programs, encryption services, firewalls, VPNS, Pen testing, vulnerability analysis etc.
The eventual aim of both the practices is to maintain the integrity of data i.e. guard against unauthorized modification or destruction of information and ensure data authenticity and non-repudiation. This will pave the way for timely and reliable access to data while maintaining its confidentiality.