Add Salt And Hash A Password With pgcrypto as a postgres til

README.md

@@ -7,7 +7,7 @@ variety of languages and technologies. These are things that don't really
 warrant a full blog post. These are mostly things I learn by pairing with
 smart people at [Hashrocket](http://hashrocket.com/).
 
-_354 TILs and counting..._
+_355 TILs and counting..._
 
 ---
 
@@ -184,6 +184,7 @@ _354 TILs and counting..._
 - [Pretty Print Data Sizes](postgres/pretty-print-data-sizes.md)
 - [Restart A Sequence](postgres/restart-a-sequence.md)
 - [Restarting Sequences When Truncating Tables](postgres/restarting-sequences-when-truncating-tables.md)
+- [Salt And Hash A Password With pgcrypto](postgres/salt-and-hash-a-password-with-pgcrypto.md)
 - [Send A Command To psql](postgres/send-a-command-to-psql.md)
 - [Set Inclusion With hstore](postgres/set-inclusion-with-hstore.md)
 - [Set A Seed For The Random Number Generator](postgres/set-a-seed-for-the-random-number-generator.md)

postgres/salt-and-hash-a-password-with-pgcrypto.md

@@ -0,0 +1,44 @@
+# Salt And Hash A Password With pgcrypto
+
+The
+[`pgcrypto`](http://www.postgresql.org/docs/current/static/pgcrypto.html)
+extension that ships with PostgreSQL can be used to do a number of
+interesting things. This includes functions for doing salted password
+hashing. Using the `crypt` and `gen_salt` functions, we can securely store a
+user password and later compare it to plain-text passwords for
+authentication purposes.
+
+```sql
+create extensions pgcrypto;
+
+select crypt('pa$$w0rd', gen_salt('bf'));
+                            crypt
+--------------------------------------------------------------
+ $2a$06$Z7wmrkYMOyLboLcULUYzNe6nHUcWywSZTt6nSrT5Xdv/VLdJ4g99K
+
+> select (
+    '$2a$06$Z7wmrkYMOyLboLcULUYzNe6nHUcWywSZTt6nSrT5Xdv/VLdJ4g99K' =
+    crypt(
+      'pa$$w0rd',
+      '$2a$06$Z7wmrkYMOyLboLcULUYzNe6nHUcWywSZTt6nSrT5Xdv/VLdJ4g99K'
+    )
+  ) as matched;
+ matched
+---------
+ t
+
+> select (
+    '$2a$06$Z7wmrkYMOyLboLcULUYzNe6nHUcWywSZTt6nSrT5Xdv/VLdJ4g99K' =
+    crypt(
+      'password',
+      '$2a$06$Z7wmrkYMOyLboLcULUYzNe6nHUcWywSZTt6nSrT5Xdv/VLdJ4g99K'
+    )
+  ) as matched;
+ matched
+---------
+ f
+```
+
+See the
+[`pgcrypt` documentation](http://www.postgresql.org/docs/current/static/pgcrypto.html) for
+more details.