diff --git a/ch04.asciidoc b/ch04.asciidoc
index 2af33346..6689b4de 100644
--- a/ch04.asciidoc
+++ b/ch04.asciidoc
@@ -184,7 +184,7 @@ An address is a string of digits and characters that can be shared with anyone w
     
 A bitcoin address derived from a public key is a string of numbers and letters that begins with the number one, such as +1J7mdg5rbQyUHENYdx39WVWK7fsLpEoXZy+. The bitcoin address is derived from the public key through the use of one-way cryptographic hashing. A "hashing algorithm" or simply "hash algorithm" is a one-way function that produces a fingerprint or "hash" of an arbitrary sized input. Cryptographic hash functions are used extensively in bitcoin: in bitcoin addresses, script addresses and in the mining "Proof-of-Work" algorithm. The algorithms used to make a bitcoin address from a public key are the Secure Hash Algorithm (SHA) and the RACE Integrity Primitives Evaluation Message Digest (RIPEMD), specifically SHA256 and RIPEMD160. 
 
-Starting with the public key K, we compute the SHA256 hash and then compute the RIPEMD160 hash of the result, producing a 160 bit (80 byte) number:
+Starting with the public key K, we compute the SHA256 hash and then compute the RIPEMD160 hash of the result, producing a 160 bit (20 byte) number:
 [latexmath]
 ++++
 \begin{equation}