Scenario: Let's says Issuer has generated fixed supply of 1000 X tokens (i.e After generating 1000 X tokens the account has been locked). Now ICO is done for 500 X tokens. Among the participants of ICO one malicious participant transferred his 100 X tokens back to Issuer to attack the fixed supply. This will create a deficiency of 100 X tokens in total supply making the total supply now only 900 X token.
How to prevent such kind of malicious attacks?