diff --git a/Related-Projects.md b/Related-Projects.md
index 4484bd5..07ce0ae 100644
--- a/Related-Projects.md
+++ b/Related-Projects.md
@@ -3,6 +3,7 @@
 * [mruby-uv](https://github.com/mattn/mruby-uv) Binding for [libuv](https://github.com/joyent/libuv) by [mattn](https://github.com/mattn)
 * [mrb-http](https://github.com/mattn/mruby-http) Binding for [http-parser](https://github.com/joyent/http-parser) by [mattn](https://github.com/mattn)
 * [mruby-md5](https://github.com/mattn/mruby-md5) MD5 digest function by [mattn](https://github.com/mattn)
+* [mruby-sha1](https://github.com/mattn/mruby-sha1) SHA1 digest function by [mattn](https://github.com/mattn)
 * [mruby-json](https://github.com/mattn/mruby-json) JSON encoder/decoder using [parson](https://github.com/kgabis/parson) by [mattn](https://github.com/mattn)
 * [mruby-sqlite3](https://github.com/mattn/mruby-sqlite3) [SQLite3](http://www.sqlite.org/) database driver by [mattn](https://github.com/mruby-sqlite3)
 * [mruby-redis](https://github.com/matsumoto-r/mruby-redis) redis client using [hiredis](https://github.com/redis/hiredis) by [matsumoto_r](https://github.com/matsumoto-r)