diff --git a/README.md b/README.md
index f4c09736..f426a7d7 100644
--- a/README.md
+++ b/README.md
@@ -93,6 +93,8 @@ API
     * `rounds` - [OPTIONAL] - the number of rounds to process the data for. (default - 10)
     * `seed_length` - [OPTIONAL] - RAND_bytes wants a length. to make that a bit flexible, you can specify a seed_length. (default - 20)
     * `cb` - [REQUIRED] - a callback to be fired once the salt has been generated. uses eio making it asynchronous.
+      * `err` - First parameter to the callback detailing any errors.
+      * `salt` - Second parameter to the callback providing the generated salt.
   * `encrypt_sync(data, salt)`
     * `data` - [REQUIRED] - the data to be encrypted.
     * `salt` - [REQUIRED] - the salt to be used in encryption.
@@ -100,6 +102,8 @@ API
     * `data` - [REQUIRED] - the data to be encrypted.
     * `salt` - [REQUIRED] - the salt to be used in encryption.
     * `cb` - [REQUIRED] - a callback to be fired once the data has been encrypted. uses eio making it asynchronous.
+      * `err` - First parameter to the callback detailing any errors.
+      * `encrypted` - Second parameter to the callback providing the encrypted form.
   * `compare_sync(data, encrypted)`
     * `data` - [REQUIRED] - data to compare.
     * `encrypted` - [REQUIRED] - data to be compared to.
@@ -107,6 +111,8 @@ API
     * `data` - [REQUIRED] - data to compare.
     * `encrypted` - [REQUIRED] - data to be compared to.
     * `cb` - [REQUIRED] - a callback to be fired once the data has been compared. uses eio making it asynchronous.
+      * `err` - First parameter to the callback detailing any errors.
+      * `same` - Second parameter to the callback providing whether the data and encrypted forms match [true | false].
 
 Hash Info
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