diff --git a/_dev/testdata/Dockerfile b/_dev/testdata/Dockerfile
new file mode 100644
index 0000000..ca3ad08
--- /dev/null
+++ b/_dev/testdata/Dockerfile
@@ -0,0 +1,26 @@
+# docker build -t tls-tris:testdata _dev/testdata
+# GOOS=linux ./_dev/go.sh test -c crypto/tls
+# docker run -it --rm -v "$(pwd):$(pwd)" -w "$(pwd)" tls-tris:testdata 
+# ./tls.test -update -test.v -test.run SCTs
+## === RUN   TestHandshakClientSCTs
+## Wrote testdata/Client-TLSv12-SCT
+## --- PASS: TestHandshakClientSCTs (0.62s)
+## PASS
+
+FROM alpine
+
+RUN apk add --update \
+		wget \
+		build-base \
+		perl \
+		ca-certificates \
+		linux-headers \
+	&& rm -rf /var/cache/apk/*
+
+RUN wget https://www.openssl.org/source/openssl-1.1.0c.tar.gz
+RUN tar xvf openssl-1.1.0c.tar.gz
+RUN cd openssl-1.1.0c && perl ./Configure enable-weak-ssl-ciphers enable-ssl3 enable-ssl3-method -static linux-x86_64
+RUN cd openssl-1.1.0c && make
+RUN cd openssl-1.1.0c && make install
+
+ENTRYPOINT ["/bin/sh"]