8. One or more non-transitory computer-readable media storing computer-executable instructions that, when executed by one or more computers, cause the one or more computers to: receive a request for a font file; determine whether the request is valid; in response to determining that the request is valid, embed a first watermark in the font file at least by inserting one or more zero-length vectors at one or more locations in the font file; and serve the font file.
9. The one or more non-transitory computer-readable media of claim 8 storing additional computer-executable instructions that, when executed, cause the one or more computers to: embed a second watermark in the font file at least by inserting one or more data tables into one or more data structures of the font file, wherein the one or more data tables include a customer identifier.