What is the different between social security insurance and social security disability?

Social Security Disability Insurance (SSDI) is financed with Social Security taxes paid by workers, employers, and self-employed persons. To be eligible for a Social Security benefit, the worker must earn sufficient credits based on taxable work to be "insured" for Social Security purposes. Disability benefits are payable to blind or disabled workers, widow(er)s, or adults disabled since childhood, who are otherwise eligible. The amount of the monthly disability benefit is based on the Social Security earnings record of the insured worker. Supplemental Security Income (SSI) is a program financed through general revenues. SSI disability benefits are payable to adults or children who are disabled or blind, have limited income and resources, meet the living arrangement requirements, and are otherwise eligible. The monthly payment varies up to the maximum federal benefit rate, which may be supplemented by the State or decreased by countable income and resources. See Understanding Supplemental Security Income for an explanation of SSI benefit payment rates