diff --git a/ch04.asciidoc b/ch04.asciidoc index ebca2878..cce2e138 100644 --- a/ch04.asciidoc +++ b/ch04.asciidoc @@ -679,7 +679,7 @@ A child private key, the corresponding public key, and the bitcoin address are a ===== Extended keys -As we saw earlier, the key derivation function can be used to create children at any level of the tree, based on the three inputs: a key, a chain code and the index of the desired child. The two essential ingredients are the key and chain code, and combined these are called an _extended key_. The term "extended key" could also be thought of as "extensible key" because such a key can be used to derive children. +As we saw earlier, the key derivation function can be used to create children at any level of the tree, based on the three inputs: a key, a chain code, and the index of the desired child. The two essential ingredients are the key and chain code, and combined these are called an _extended key_. The term "extended key" could also be thought of as "extensible key" because such a key can be used to derive children. Extended keys are stored and represented simply as the concatenation of the 256-bit key and 256-bit chain code into a 512-bit sequence. There are two types of extended keys. An extended private key is the combination of a private key and chain code and can be used to derive child private keys (and from them, child public keys). An extended public key is a public key and chain code, which can be used to create child public keys, as described in <>.