# Tag Info

As @yyyyyy already commented: if you are able to successfully apply a length extension attack, you would be able to compute $$\operatorname{SHA256}(\mathit{secret}\Vert\mathit{padding}\Vert\mathit{data})$$ But computing $\operatorname{SHA256}(\mathit{secret}\Vert\mathit{data})$ for freely chosen $\mathit{data}$ without the $\mathit{padding}$ in between is ...