Abstract :With the improvement of communication technology a desire for secure
communication also arises and that is fulfilled by different data security techniques like cryptography, digital
applies, watermarking etc. Cryptography is an data encryption /decryption technique used for network security
when different networks are interconnected. It is used to secure the data transmission from attacks and
intrusions. Security of data is one of the foremost vital factors of information technology. Aadhaar number is a
12-digit unmistakable number issued by the Indian government to every individual occupant of India. It is
distinctive number that will capture all demographic and biometric data, of each resident Indian individual. This
paper is split into 6 sections contain components of cryptography, types of encryption algorithms, comparison of
algorithms, mode of data security in Aadhaar, encryption techniques applied in Aadhaar, challenges in Aadhaar
security