Corrections to tutorials/Analyzing_privacy_of_transaction.md

Author: delcin-raj

Diff for: blockchain_analysis/src/main.rs

@@ -53,7 +53,9 @@ fn main() {
     // track_utxo_set_10(&rpc_client, 831200).unwrap();
     let res = txs_sort_unique_input_addrs(&rpc_client, 144008).unwrap();
 
-    for r in res {
+    // Displaying the top 10 transactions with greatest input addresses
+    for i in 0..10 {
+        let r = &res[i];
         println!("Transaction = {}, uses {} addresses", r.0.txid(), r.1);
     }
 }

Diff for: blockchain_analysis/src/privacy.rs

@@ -9,22 +9,28 @@ pub fn txs_sort_unique_input_addrs(
     client: &Client,
     block_height: u64,
 ) -> Result<Vec<(Transaction, u32)>, bitcoincore_rpc::Error> {
-    let block_hash = client.get_block_hash(block_height)?;
-    println!("block hash {}", block_hash);
     let block = get_block(block_height, client)?;
     let txs = block.txdata;
 
     let mut result: Vec<(Transaction, u32)> = vec![];
     for tx in txs.iter() {
+        if tx.is_coinbase() {
+            continue;
+        }
         let mut input_addrs: HashSet<Address> = HashSet::new();
+
         for input in tx.input.iter() {
-            let prev_tx =
-                client.get_raw_transaction(&input.previous_output.txid, Some(&block_hash))?;
-            let prev_tx_output = &prev_tx.output[input.previous_output.vout as usize];
-            let prev_tx_script = &prev_tx_output.script_pubkey;
-            let input_address = Address::from_script(prev_tx_script, Network::Bitcoin)
-                .expect("Failed to parse address from scriptPubKey");
-            input_addrs.insert(input_address);
+            if let Ok(prev_tx) = client.get_raw_transaction(&input.previous_output.txid, None) {
+                let prev_tx_output = &prev_tx.output[input.previous_output.vout as usize];
+                let prev_tx_script = &prev_tx_output.script_pubkey;
+                if let Ok(input_address) = Address::from_script(prev_tx_script, Network::Bitcoin) {
+                    input_addrs.insert(input_address);
+                } else {
+                    println!("`Address::from_script` only recognizes p2sh, p2pkh and their respective segwit variants");
+                }
+            } else {
+                println!("Unknown transaction id of an input {}", &input.previous_output.txid);
+            }
         }
         result.push((tx.clone(), input_addrs.len() as u32));
     }

Diff for: tutorials/Analyzing_privacy_of_transaction.md

@@ -75,7 +75,7 @@ fn extract_from_TxIn(input: TxIn) -> bitcoin::Address {
 // In bitcoin crate TxIn is defined like the following
 struct TxIn {
     pub previous_output: OutPoint,
-    pub script_sig: ScriptBuf, // It is not possible to extract address directly from here using current implementations
+    pub script_sig: ScriptBuf, // contains signature and public key data
     pub sequence: Sequence,
     pub witness: Witness,
 }
@@ -89,6 +89,7 @@ struct OutPoint {
 }
 ```
 
+
 So in order to extract address from the transaction input we have to get information
 about the transaction where the input was the output (TxOut).
 The following code demonstrates how to do it,