From 58643749fb35dac6de2100ca98fa50910309dcbe Mon Sep 17 00:00:00 2001 From: "David A. Harding" Date: Sat, 4 Feb 2023 14:36:36 -1000 Subject: [PATCH] CH02::getting inputs: warn about privacy for address lookup calls --- ch02.asciidoc | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-) diff --git a/ch02.asciidoc b/ch02.asciidoc index 3d09c096..280acae6 100644 --- a/ch02.asciidoc +++ b/ch02.asciidoc @@ -50,6 +50,8 @@ information from the Bitcoin network. With each transaction or block example, we will provide a URL so you can look it up yourself and study it in detail. +[[block-explorer-privacy]] +.Block explorer privacy warning [WARNING] ==== Searching information on a block explorer may disclose to its operator @@ -354,15 +356,18 @@ However, because full nodes use more resources, most user wallets run "lightweight" clients that track only the user's own UTXOs. -If the wallet application does not maintain a copy of unspent -transaction outputs, it can query the Bitcoin network to retrieve this +If the wallet application does not maintain a copy of all UTXOs, it can +query the Bitcoin network to retrieve this information using a variety of APIs available by different providers or -by asking a full-node using an application programming interface (API) +by asking a full node using an application programming interface (API) call. <> shows an API request, constructed as an HTTP GET command to a specific URL. This URL will return all the unspent transaction outputs for an address, giving any application the information it needs to construct transaction inputs for spending. We use the simple command-line HTTP client _cURL_ to retrieve the response. +Note that looking up information using a third-party API like this is similar to +using a block explorer; see the privacy warning in +<>. [[example_2-2]] .Look up all the unspent outputs for Alice's Bitcoin address