OTP stands One Time Password service , mobile phone and online logging on the system used now increasing day by day, indeed! The using of a mobile phone but along with this mobile data stolen also increasing, to secure the data stolen, OTP password method levied in the so many & various sector The keyword uses for this terminology is OTP and mobile user authentication . The (OTP) the one-time password is valid for a short interval of time and single transaction or login is that password which will not plan in the database instead of it will use like password and will apply at the same time, after some time it will expire It contains some four to six-digit number might be complete numeric or alphanumeric that which you have to use in some online services like if you are purchasing some products online by any of website portal like Amazon, Flipkart, etc. , also if you are using any internet banking that time for security purpose you will have to use it...