CH04::privkeys: remove address function from here

We'll describe the commitment in the P2PKH section and base58check in
its section.

ch04.asciidoc

@@ -71,17 +71,7 @@ pairs, each consisting of a private key and a public key. The private
 key (k) is a number, usually derived from a number picked at random.
 From the private key, we
 use elliptic curve multiplication, a one-way cryptographic function, to
-generate a public key (K). From the public key (K), we use a one-way
-cryptographic hash function to generate a Bitcoin address (A). In this
-section, we will start with generating the private key, look at the
-elliptic curve math that is used to turn that into a public key, and
-finally, generate a Bitcoin address from the public key. The
-relationship between private key, public key, and Bitcoin address is
-shown in <<k_to_K_to_A>>.
-
-[[k_to_K_to_A]]
-.Private key, public key, and Bitcoin address
-image::images/mbc2_0401.png["privk_to_pubK_to_addressA"]
+generate a public key (K).
 
 .Why Use Asymmetric Cryptography (Public/Private Keys)?
 ****
@@ -352,9 +342,8 @@ resulting public key, a point on the curve. Because the generator point
 is always the same for all bitcoin users, a private key _k_ multiplied
 with _G_ will always result in the same public key _K_. The relationship
 between _k_ and _K_ is fixed, but can only be calculated in one
-direction, from _k_ to _K_. That's why a Bitcoin address (derived from
-_K_) can be shared with anyone and does not reveal the user's private
-key (_k_).
+direction, from _k_ to _K_. That's why a Bitcoin public key can be
+shared with anyone and does not reveal the user's private key (_k_).
 
 [TIP]
 ====