Made changes to ch04.asciidoc

ch04.asciidoc

@@ -968,8 +968,7 @@ In both cases, one of the risks of using a single fixed address (rather than a s
 | *Vanity (6 character match)* | 1J7mdg5WxGENmwyJP9xuGhG5KRzu99BBCX
 |=======
 
-So does a vanity address increase security? If Eugenia generates the vanity address +1Kids33q44erFfpeXrmDSz7zEqG2FesZEN+, 
-users are likely to look at the vanity pattern word _and a few characters beyond_, for example noticing the "1Kids33" part of the address. That would force an attacker to generate a vanity address matching at least six characters (two more), expending an effort that is 3,364 times (58 × 58) higher than the effort Eugenia expended for her four-character vanity. Essentially, the effort Eugenia expends (or pays a vanity pool for) "pushes" the attacker into having to produce a longer pattern vanity. If Eugenia pays a pool to generate an 8-character vanity address, the attacker would be pushed into the realm of 10 characters, which is infeasible on a personal computer and expensive even with a custom vanity-mining rig or vanity pool. What is affordable for Eugenia becomes unaffordable for the attacker, especially if the potential reward of fraud is not high enough to cover the cost of the vanity address generation.(((range="endofrange", startref="ix_ch04-asciidoc27")))(((range="endofrange", startref="ix_ch04-asciidoc26"))) 
+So does a vanity address increase security? If Eugenia generates the vanity address +1Kids33q44erFfpeXrmDSz7zEqG2FesZEN+, users are likely to look at the vanity pattern word _and a few characters beyond_, for example noticing the "1Kids33" part of the address. That would force an attacker to generate a vanity address matching at least six characters (two more), expending an effort that is 3,364 times (58 × 58) higher than the effort Eugenia expended for her four-character vanity. Essentially, the effort Eugenia expends (or pays a vanity pool for) "pushes" the attacker into having to produce a longer pattern vanity. If Eugenia pays a pool to generate an 8-character vanity address, the attacker would be pushed into the realm of 10 characters, which is infeasible on a personal computer and expensive even with a custom vanity-mining rig or vanity pool. What is affordable for Eugenia becomes unaffordable for the attacker, especially if the potential reward of fraud is not high enough to cover the cost of the vanity address generation.(((range="endofrange", startref="ix_ch04-asciidoc27")))(((range="endofrange", startref="ix_ch04-asciidoc26"))) 
 
 [[paper_wallets]]
 ==== Paper Wallets