From 0c5b41f0cefb45aff76b7f1be19a25fc2ffee55e Mon Sep 17 00:00:00 2001
From: Taylor Hornby <havoc@defuse.ca>
Date: Tue, 15 Dec 2015 01:26:04 -0700
Subject: [PATCH] Copy zcutil/fetch-params.sh from the private alpha branch,
 changing the file names.

---
 zcutil/fetch-params.sh | 69 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 69 insertions(+)
 create mode 100755 zcutil/fetch-params.sh

diff --git a/zcutil/fetch-params.sh b/zcutil/fetch-params.sh
new file mode 100755
index 000000000..55e1c362a
--- /dev/null
+++ b/zcutil/fetch-params.sh
@@ -0,0 +1,69 @@
+#!/bin/bash
+
+set -eu
+
+PARAMS_DIR="$HOME/.zcash-params"
+
+REGTEST_PKEY_NAME='zc-testnet-public-alpha-proving.key'
+REGTEST_VKEY_NAME='zc-testnet-public-alpha-verification.key'
+REGTEST_PKEY_URL="https://zca.sh/downloads/$REGTEST_PKEY_NAME"
+REGTEST_VKEY_URL="https://zca.sh/downloads/$REGTEST_VKEY_NAME"
+REGTEST_DIR="$PARAMS_DIR/regtest"
+
+
+# Note: This assumes cwd is set appropriately!
+function fetch_params {
+    local url="$1"
+    local filename="$(echo "$url" | sed 's,^.*/,,')"
+    if ! [ -f "$filename" ]
+    then
+        echo "Retrieving: $url"
+        wget --progress=dot:giga "$url"
+    fi
+}
+
+cat <<EOF
+zcash - fetch-params.sh
+
+EOF
+
+# Now create PARAMS_DIR and insert a README if necessary:
+if ! [ -d "$PARAMS_DIR" ]
+then
+    mkdir -p "$PARAMS_DIR"
+    README_PATH="$PARAMS_DIR/README"
+    cat >> "$README_PATH" <<EOF
+This directory stores common zcash zkSNARK parameters. Note that is is
+distinct from the daemon's -datadir argument because the parameters are
+large and may be shared across multiple distinct -datadir's such as when
+setting up test networks.
+EOF
+
+    # This may be the first time the user's run this script, so give
+    # them some info, especially about bandwidth usage:
+    cat <<EOF
+This script will fetch the zerocash zkSNARK parameters and verify their
+integrity with sha256sum.
+
+The parameters currently are about 2GiB in size, so plan accordingly
+for your bandwidth constraints. If the files are already present and
+have the correct sha256sum, no networking is used.
+
+Creating params directory. For details about this directory, see:
+$README_PATH
+
+EOF
+fi
+
+mkdir -p "$REGTEST_DIR"
+cd "$REGTEST_DIR"
+
+fetch_params "$REGTEST_PKEY_URL"
+fetch_params "$REGTEST_VKEY_URL"
+
+# Now verify their hashes:
+echo 'Verifying parameter file integrity via sha256sum...'
+sha256sum --check - <<EOF
+bc03442cc53fa53a681809afa64c91e8c37d2db1f51eb2355e4fe181d24ce878  $REGTEST_PKEY_NAME
+67d60eeb10541ec2086e56d8dffa850e371b69ddb82fc5686c26921ad2b0f654  $REGTEST_VKEY_NAME
+EOF