HFF Black Steel is based on Acier Noir, from page 1 of "Moderne Alphabets: 100 Complete Fonts" by Dan X. Solo, first published by Dover Publications in 1999. Acier Noir is also listed in page 55 0f "The Solotype Catalog of 4,147 Display Typefaces". HFF Black Steel is a free font. You are free to use this font in any way you want to. You can share this font with others if you wished to. Use freely, share freely and, most of all, enjoy the font.