diff --git a/ch04.asciidoc b/ch04.asciidoc
index f0728327..fda3528e 100644
--- a/ch04.asciidoc
+++ b/ch04.asciidoc
@@ -253,7 +253,7 @@ image::images/msbt_0405.png["pubkey_to_address"]
 ==== Base58 and Base58Check Encoding
 
 [[base58]]
-===== Base-58 Encoding
+===== Base-58 encoding
 
 In order to represent long numbers in a compact way, using fewer symbols, many computer systems use mixed-alphanumeric representations with a base (or radix) higher than 10. For example, whereas the traditional decimal system uses the 10 numerals 0 through 9, the hexadecimal system uses 16, with the letters A through F as the six additional symbols. A number represented in hexadecimal format is shorter than the equivalent decimal representation. Even more compact, Base-64 representation uses 26 lower-case letters, 26 capital letters, 10 numerals, and two more characters such as "\+" and "/" to transmit binary data over text-based media such as email. Base-64 is most commonly used to add binary attachments to email. Base58 is a text-based binary-encoding format developed for use in bitcoin and used in many other crypto-currencies. It offers a balance between compact representation, readability, and error detection and prevention. Base58 is a subset of Base64, using the upper- and lowercase letters and numbers, but omitting some characters that are frequently mistaken for one another and can appear identical when displayed in certain fonts. Specifically, Base58 is Base64 without the 0 (number zero), O (capital o), l (lower L), I (capital i), and the symbols "\+" and "/". Or, more simply, it is a set of lower and capital letters and numbers without the four (0, O, l, I) just mentioned.