Merge pull request bitcoin#389 from ImranLorgat/patch-15

Glossary - Private Channel

glossary.asciidoc

@@ -360,6 +360,14 @@ peer::
 Penalty Transaction::
     Look at the Breach Remedy Transaction.
 
+private channel:
+    A channel not announced to the rest of the network. 
+    Technically "private" is a misnomer as these channels can still be identified through routing hints and commitment transactions.
+    We suggest they are better described as "unannounced" channels.
+    With an unannounced channel, the channel partners can send and receive payments between each other as normal.
+    However the rest of the network will not be aware of it and so cannot typically use it to route payments.
+    As the number of and capacity of unanounced channels is unknown, the total public channel count and capacity only accounts for a portion of the total Lightning Network.
+
 preimage::
     In mathematics, given a function $f$ and a value $h$ the preimage of $h$ with respect to $f$ is the set of values $R = \{r_1,r_2,...\}$ such that $f(r_i) = h$ for all $\r_i \in R$.
     In layman's terms, it is the set of values which is mapped to $h$ by the function $f$.
@@ -368,6 +376,7 @@ preimage::
     Cryptographers use the term preimage for an arbitrary element of $R$.
     In particular, when using SHA-256 we should state that each element has an infinite amount of preimages.
     Yet it is still believed to be computationally hard to find such a preimage.
+
 proof of work::
     A piece of data that requires significant computation to find. In Bitcoin, miners must find a numeric solution to the SHA256 algorithm that meets a network-wide target, the difficulty target.