diff --git a/httpie_hmac/httpie_hmac.py b/httpie_hmac/httpie_hmac.py
index a50977e..0057fc0 100644
--- a/httpie_hmac/httpie_hmac.py
+++ b/httpie_hmac/httpie_hmac.py
@@ -10,6 +10,7 @@
 import hashlib
 import hmac
 import importlib.machinery
+import io
 import os
 import requests
 import types
@@ -143,6 +144,8 @@ def __call__(self, r):
         content_type = r.headers.get('content-type')
         if not content_type:
             content_type = ''
+        else:
+            content_type = content_type.decode('utf-8')
 
         # If content-md5 is already given, use it, otherwise calculate
         # it ourselves and add it to the headers
@@ -150,11 +153,21 @@ def __call__(self, r):
         if not content_md5:
             if content_type and r.body:
                 m = hashlib.md5()
+                body = r.body
+                # If we have a buffer, convert it in to a string
+                if type(r.body) == io.BufferedReader:
+                    body = body.read()
+                    r.body = body
                 m.update(r.body)
-                content_md5 = base64.b64encode(m.digest()).rstrip()
+                content_md5 = base64 \
+                    .b64encode(m.digest()) \
+                    .rstrip() \
+                    .decode('utf-8')
                 r.headers['Content-MD5'] = content_md5
             else:
                 content_md5 = ''
+        else:
+            content_md5 = content_md5.decode('utf-8')
 
         # If date is given already, use it - otherwise generate it
         # ourselves and add it to the headers
@@ -163,6 +176,8 @@ def __call__(self, r):
             now = datetime.datetime.utcnow()
             http_date = now.strftime('%a, %d %b %Y %H:%M:%S GMT')
             r.headers['Date'] = http_date
+        else:
+            http_date = http_date.decode('utf-8')
 
         # Get the path from the UL
         url = urlparse(r.url)
diff --git a/pyproject.toml b/pyproject.toml
index ba384b5..092a15f 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -4,7 +4,7 @@ build-backend = "setuptools.build_meta"
 
 [project]
 name = "httpie-hmac"
-version = "1.1.1"
+version = "1.2.0"
 authors = [
     {name = "Martyn Pittuck-Schols", email = "martyn@rustfoo.com"},
 ]