Update hashing.md

docs/api/hashing.md

@@ -65,6 +65,43 @@ const isMatch = Bun.password.verifySync(password, hash);
 // => true
 ```
 
+### Salt
+
+When you use `Bun.password.hash`, a salt is automatically generated and included in the hash.
+
+#### Modular Crypt Format
+
+In the following [Modular Crypt Format](https://passlib.readthedocs.io/en/stable/modular_crypt_format.html) hash (used by `bcrypt`):
+
+```sh
+$2b$10$Lyj9kHYZtiyfxh2G60TEfeqs7xkkGiEFFDi3iJGc50ZG/XJ1sxIFi;
+```
+
+The format is composed of:
+
+- `bcrypt`: `$2b`
+- `rounds`: `$10` - rounds (log10 of the actual number of rounds)
+- `salt`: `$Lyj9kHYZtiyfxh2G60TEfeqs7xkkGiEFFDi3iJGc50ZG/XJ1sxIFi`
+- `hash`: `$GzJ8PuBi+K+BVojzPfS5mjnC8OpLGtv8KJqF99eP6a4`
+
+#### PHC format
+
+In the following [PHC format](https://github.com/P-H-C/phc-string-format/blob/master/phc-sf-spec.md) hash (used by `argon2`):
+
+```sh
+$argon2id$v=19$m=65536,t=2,p=1$xXnlSvPh4ym5KYmxKAuuHVlDvy2QGHBNuI6bJJrRDOs$2YY6M48XmHn+s5NoBaL+ficzXajq2Yj8wut3r0vnrwI
+```
+
+The format is composed of:
+
+- `argon2id`: `$argon2id`
+- `version`: `$v=19`
+- `memory cost`: `65536`
+- `iterations`: `t=2`
+- `parallelism`: `p=1`
+- `salt`: `$xXnlSvPh4ym5KYmxKAuuHVlDvy2QGHBNuI6bJJrRDOs`
+- `hash`: `$2YY6M48XmHn+s5NoBaL+ficzXajq2Yj8wut3r0vnrwI`
+
 ## `Bun.hash`
 
 `Bun.hash` is a collection of utilities for _non-cryptographic_ hashing. Non-cryptographic hashing algorithms are optimized for speed of computation over collision-resistance or security.