zcash-patched-for-explorer/zcutil/fetch-params.sh

#!/bin/bash

set -eu

PARAMS_DIR="$HOME/.zcash-params"

REGTEST_PKEY_NAME='z3-proving.key'
REGTEST_VKEY_NAME='z3-verification.key'
REGTEST_PKEY_URL="https://z.cash/downloads/$REGTEST_PKEY_NAME"
REGTEST_VKEY_URL="https://z.cash/downloads/$REGTEST_VKEY_NAME"
REGTEST_DIR="$PARAMS_DIR/regtest"

# This should have the same params as regtest. We use symlinks for now.
TESTNET3_DIR="$PARAMS_DIR/testnet3"


function fetch_params {
    local url="$1"
    local output="$2"
    local dlname="${output}.dl"

    if ! [ -f "$output" ]
    then
        echo "Retrieving: $url"
        # Note: --no-check-certificate should be ok, since we rely on
        # sha256 for integrity, and there's no confidentiality requirement.
        # Our website uses letsencrypt certificates which are not supported
        # by some wget installations, so we expect some cert failures.
        wget \
            --progress=dot:giga \
            --no-check-certificate \
            --output-document="$dlname" \
            --continue \
            "$url"

        # Only after successful download do we update the parameter load path:
        mv -v "$dlname" "$output"
    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 Zcash 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"

fetch_params "$REGTEST_PKEY_URL" "$REGTEST_DIR/$REGTEST_PKEY_NAME"
fetch_params "$REGTEST_VKEY_URL" "$REGTEST_DIR/$REGTEST_VKEY_NAME"

echo 'Updating testnet3 symlinks to regtest parameters.'
mkdir -p "$TESTNET3_DIR"
ln -sf "../regtest/$REGTEST_PKEY_NAME" "$TESTNET3_DIR/$REGTEST_PKEY_NAME"
ln -sf "../regtest/$REGTEST_VKEY_NAME" "$TESTNET3_DIR/$REGTEST_VKEY_NAME"

cd "$PARAMS_DIR"

# Now verify their hashes:
echo 'Verifying parameter file integrity via sha256sum...'
sha256sum --check - <<EOF
faa9acb74817a82a3c16466379160434cf7e267e3e15e2c36f0cdbb95cdff193  regtest/$REGTEST_PKEY_NAME
faa9acb74817a82a3c16466379160434cf7e267e3e15e2c36f0cdbb95cdff193  testnet3/$REGTEST_PKEY_NAME
3bd93d95c3ba525f79e14a241c3e302e7e461baa863b3836228f12933ddda472  regtest/$REGTEST_VKEY_NAME
3bd93d95c3ba525f79e14a241c3e302e7e461baa863b3836228f12933ddda472  testnet3/$REGTEST_VKEY_NAME
EOF