diff --git a/ch11.asciidoc b/ch11.asciidoc
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--- a/ch11.asciidoc
+++ b/ch11.asciidoc
@@ -53,7 +53,7 @@ Over the past three years, as a direct result of bitcoin adoption, we have seen
 
 ==== Hardware Wallets
 
-In the long term, bitcoin security increasingly will take the form of hardware tamper-proof wallets. Unlike a smartphone or desktop computer, a bitcoin hardware wallet has just one purpose: to hold bitcoin securely. Without general-purpose software to compromise and with limited interfaces, hardware wallets can deliver an almost foolproof level of security to nonexpert users. I expect to see hardware wallets become the predominant method of bitcoin storage. For an example of such a hardware wallet, see the https://trezor.io/[Trezor].
+((("Trezor bitcoin hardware wallet")))((("wallets", "hardware wallets")))((("hardware wallets")))In the long term, bitcoin security increasingly will take the form of hardware tamper-proof wallets. Unlike a smartphone or desktop computer, a bitcoin hardware wallet has just one purpose: to hold bitcoin securely. Without general-purpose software to compromise and with limited interfaces, hardware wallets can deliver an almost foolproof level of security to nonexpert users. I expect to see hardware wallets become the predominant method of bitcoin storage. For an example of such a hardware wallet, see the https://trezor.io/[Trezor].
 
 ==== Balancing Risk