add README.md

1 files changed, 22 insertions, 0 deletions

diff --git a/README.md b/README.md
new file mode 100644
index 0000000..d41d4ac
--- /dev/null
+++ b/README.md
@@ -0,0 +1,22 @@
+# cryptopals
+
+nothing exciting. just trying out the challenges from
+[cryptopals.com][cp].
+
+[cp]: https://cryptopals.com
+
+## building
+
+requires `go >= 1.15` and `make`.
+
+```bash
+ make
+```
+
+will build everything.
+
+## running
+
+```bash
+ ./cryptopals -c CHALLENGE_NUM
+```