Edited ch06_transactions.adoc with Atlas code editor

ch06_transactions.adoc

@@ -759,7 +759,7 @@ simple equation wouldn't be secure.  As we'll see in <<c_signatures>>, an
 unforgeable digital signature scheme uses an equation that can only be
 solved by someone in possession of certain data that they're able to
 keep secret.  They're able to reference that secret data using a public
-identifier.  That public identifier is called a _public key_ and a
+identifier.  That public identifier is ((("public keys")))((("signatures")))called a _public key_ and a
 solution to the equation is called a _signature_.
 
 The following script contains a public key and an opcode that requires