S. 68: Cash credits – Survey- Demonetization – Purchase of gold from sale proceeds – Sales cannot be assessed as undisclosed income – Only profit thereon could be taxed as income- Entire sales cannot be assessed as undislosed income – Provision of section 115BBE is cannot be made retrospectively – For the assessment year 2017-18 only net profit was directed to be taxed . [ S.115BBE 132 , 133A ]