Edited ch04_keys.adoc with Atlas code editor

ch04_keys.adoc

@@ -10,7 +10,13 @@ Bitcoin payments that Bob receives.  The method Alice uses must ensure
 that only Bob can further spend the bitcoins he receives.
 
 The original Bitcoin paper describes a very simple scheme for achieving
-those goals, shown in <<pay-to-pure-pubkey>>.  A receiver like Bob
+those goals, shown in <<pay-to-pure-pubkey>>.  
+
+[[pay-to-pure-pubkey]]
+.Transaction chain from original Bitcoin paper
+image::images/mbc3_aain01.png["Transaction chain from original Bitcoin paper"]
+
+A receiver like Bob
 accepts bitcoins to a public key in a transaction that is signed by the
 spender (like Alice).  The bitcoins that Alice is spending had been
 previously received to one of her public keys, and she uses the
@@ -18,10 +24,6 @@ corresponding private key to generate her signature.  Full nodes can
 verify that Alice's signature commits to the output of a hash function
 that itself commits to Bob's public key and other transaction details.
 
-[[pay-to-pure-pubkey]]
-.Transaction chain from original Bitcoin paper
-image::images/mbc3_aain01.png["Transaction chain from original Bitcoin paper"]
-
 We'll examine public keys, private keys, signatures, and hash functions
 in this chapter, and then use all of them together to describe
 the addresses used by modern Bitcoin software.