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

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

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+# 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.