diff --git a/01.md b/01.md
index ec872c30..ecac6f6c 100644
--- a/01.md
+++ b/01.md
@@ -29,7 +29,7 @@ The only object type that exists is the `event`, which has the following format
 }
 ```
 
-To obtain the `event.id`, we `sha256` the serialized event. The serialization is done over the UTF-8 JSON-serialized string (with no white space or line breaks between the fields) of the following structure:
+To obtain the `event.id`, we `sha256` the serialized event. The serialization is done over the UTF-8 JSON-serialized string (which is described below) of the following structure:
 
 ```
 [
@@ -42,6 +42,18 @@ To obtain the `event.id`, we `sha256` the serialized event. The serialization is
 ]
 ```
 
+To prevent implementation differences from creating a different event ID for the same event, the following rules MUST be followed while serializing:
+- No whitespace, line breaks or other unnecessary formatting should be included in the output JSON.
+- No characters except the following should be escaped, and instead should be included verbatim:
+  - A line break, `0x0A`, as `\n`
+  - A double quote, `0x22`, as `\"`
+  - A backslash, `0x5C`, as `\\`
+  - A carriage return, `0x0D`, as `\r`
+  - A tab character, `0x09`, as `\t`
+  - A backspace, `0x08`, as `\b`
+  - A form feed, `0x0C`, as `\f`
+- UTF-8 should be used for encoding.
+
 ### Tags
 
 Each tag is an array of strings of arbitrary size, with some conventions around them. Take a look at the example below: