Add tool to extract zkeys from wallet.dat (need db_dump 6.2)

Cargo.toml

@@ -15,6 +15,11 @@ name = "warp-rpc"
 path = "src/main/rpc.rs"
 required-features = ["rpc"]
 
+[[bin]]
+name = "wallet"
+path = "src/main/wallet.rs"
+required-features = ["dotenv"]
+
 #[[bin]]
 #name = "ledger"
 #path = "src/main/ledger.rs"

src/main/wallet.rs

@@ -0,0 +1,38 @@
+use std::fs::File;
+use std::io::{BufRead, BufReader};
+use anyhow::Result;
+use zcash_client_backend::encoding::encode_extended_spending_key;
+use zcash_primitives::consensus::Network::MainNetwork;
+use zcash_primitives::consensus::Parameters;
+use zcash_primitives::zip32::ExtendedSpendingKey;
+
+fn main() -> Result<()> {
+    env_logger::init();
+    dotenv::dotenv()?;
+    let wallet_dump_path = dotenv::var("WALLET_DUMP_PATH")?;
+    let file = File::open(&wallet_dump_path)?;
+    let reader = BufReader::new(file);
+    let mut started = false;
+    let mut key = String::new();
+    for (i, line) in reader.lines().enumerate() {
+        let ln = line?.trim_start().to_string();
+        if !started && ln != "HEADER=END" { continue; } // skip header
+        started = true;
+        if ln == "DATA=END" { break } // stop at data end
+        if i % 2 == 1 {
+            let k = hex::decode(ln).unwrap();
+            let len = k[0] as usize;
+            key = String::from_utf8_lossy(&k[1..=len]).to_string(); // collect key name
+        }
+        else {
+            let value = ln;
+            if key == "sapzkey" {
+                let sapkey = hex::decode(value).unwrap(); // export secret key
+                let s = ExtendedSpendingKey::read(&*sapkey).unwrap();
+                println!("{}", encode_extended_spending_key(MainNetwork.hrp_sapling_extended_spending_key(), &s));
+            }
+        }
+    }
+
+    Ok(())
+}