I can't say I did anything wrong.和I can't say I did nothing

1.I can't say I did anything wrong.我不能说我做错什么了（意思是我做的是对的,至少说话的时候没有意识到自己有错）
2.I can't say I did nothing wrong.我不能说我没做错（承认有错）
按我的理解第一句I can't say I did anything wrong等同于I can say I did nothing wrong,而第二句 I can't say I did nothing wrong等同于I can say I did something wrong.