Fix spec spelling typo
@@ -27,7 +27,7 @@ called "objectivity." Simply put, proof of work cannot be forged and no outside
information is needed to check its validity. Without knowing the history of the
chain, we can examine a Bitcoin block header and determine (probabilistically)
how many hashes were performed to generate it. The number of hashes used to
-generate a header represents an unforgable cost inherent to that header,
+generate a header represents an unforgeable cost inherent to that header,
independent of its context or history.
Contrast this with Proof of Stake, in which the cost of generating a header is
