The phrase "are difficult to forge" is correct and usable in written English.
It can be used when discussing items, documents, or concepts that are hard to replicate or counterfeit.
Example: "The signatures on these legal documents are difficult to forge, ensuring their authenticity."
Alternatives: "are hard to replicate" or "are challenging to counterfeit."
Furthermore, steels, which are difficult to forge but nonetheless have high potential for specific applications (such as high strength or corrosion resistant steels), can also be processed.
However, the alloys employed in the euros cupro-nickel and nickeuros cupro-nickel been used to mand hard-wearinickel-brass have difficult to forge.
These are difficult to forge when so many of the positions that Mr. Bolton has taken reflect unpopular United States policies not of his making.
And though they are difficult to forge, such robust relationships are more likely to endure the ups and downs the market inevitably deals any organization.
This forms the basis of an optical security system, whereby documents are encoded with practically invisible phase masks (such masks are difficult to forge), which may then be rapidly screened to verify the authenticity of the documents.
He believes it could also be incorporated into documents and banknotes as a security feature because the metals are difficult to forge.
The phone recognises the hidden unique pattern of the iris, which is set after about the age of two and is difficult to forge.
Long-term structural reforms require a "political settlement" different from what exists today – and that will be difficult to forge in this unstable environment.
It would be difficult to forge a more harmonious union of cast, director and script than the one created at the Variety Arts Theater, where Daniel Sullivan's unflinching production of Donald Margulies's rueful play is ending its run.
It would be difficult to forge a more harmonious union of cast, director and script than the one created at the Variety Arts Theater, where Daniel Sullivan's unflinching production of Donald Margulies's rueful play deserves a long and healthy run.
