Verify LTC core.

Dockerfile

@@ -4,6 +4,7 @@ ENV LANG=C.UTF-8 \
     PARTICL_DATADIR="/coindata/particl" \
     PARTICL_BINDIR="/opt/particl" \
     LITECOIN_BINDIR="/opt/litecoin" \
+    LITECOIN_VERSION="0.17.1" \
     DATADIRS="/coindata"
 
 RUN apt-get update; \
@@ -16,10 +17,16 @@ RUN cd ~; \
     pip3 install .; \
     pip3 install pyzmq plyvel protobuf;
 
-RUN PARTICL_VERSION=0.18.0.12 PARTICL_VERSION_TAG= PARTICL_ARCH=x86_64-linux-gnu_nousb.tar.gz coldstakepool-prepare --update_core; \
-    wget https://download.litecoin.org/litecoin-0.17.1/linux/litecoin-0.17.1-x86_64-linux-gnu.tar.gz; \
-    mkdir -p ${LITECOIN_BINDIR}; \
-    tar -xvf litecoin-0.17.1-x86_64-linux-gnu.tar.gz -C ${LITECOIN_BINDIR} --strip-components 2 litecoin-0.17.1/bin/litecoind litecoin-0.17.1/bin/litecoin-cli
+RUN PARTICL_VERSION=0.18.0.12 PARTICL_VERSION_TAG= PARTICL_ARCH=x86_64-linux-gnu_nousb.tar.gz coldstakepool-prepare --update_core && \
+    mkdir -p ${LITECOIN_BINDIR} && cd ${LITECOIN_BINDIR} && \
+    wget https://download.litecoin.org/litecoin-${LITECOIN_VERSION}/linux/litecoin-${LITECOIN_VERSION}-x86_64-linux-gnu.tar.gz && \
+    wget -O build.assert https://github.com/litecoin-project/gitian.sigs.ltc/raw/master/${LITECOIN_VERSION}-linux/thrasher/litecoin-linux-0.17-build.assert && \
+    wget -O build.assert.sig https://github.com/litecoin-project/gitian.sigs.ltc/raw/master/${LITECOIN_VERSION}-linux/thrasher/litecoin-linux-0.17-build.assert.sig && \
+    wget -qO - https://raw.githubusercontent.com/litecoin-project/litecoin/master/contrib/gitian-keys/thrasher-key.pgp | gpg --import - && \
+    gpg --verify build.assert.sig build.assert && \
+    grep " litecoin-${LITECOIN_VERSION}-x86_64-linux-gnu.tar.gz\$" build.assert | sha256sum -c - && \
+    tar -xvf litecoin-${LITECOIN_VERSION}-x86_64-linux-gnu.tar.gz -C ${LITECOIN_BINDIR} --strip-components 2 litecoin-${LITECOIN_VERSION}/bin/litecoind litecoin-${LITECOIN_VERSION}/bin/litecoin-cli && \
+    rm litecoin-${LITECOIN_VERSION}-x86_64-linux-gnu.tar.gz && rm *.assert*
 
 # TODO: move coindata dir out of src dir
 RUN wget -O bs.zip https://github.com/tecnovert/basicswap/archive/master.zip; \