diff --git a/awscurl/awscurl.py b/awscurl/awscurl.py
index cf09318..3a99f5a 100755
--- a/awscurl/awscurl.py
+++ b/awscurl/awscurl.py
@@ -16,6 +16,7 @@ import configparser
 import configargparse
 import requests
 from requests.structures import CaseInsensitiveDict
+from urllib.parse import quote
 
 
 from .utils import sha256_hash, sha256_hash_for_binary_data, sign
@@ -315,11 +316,24 @@ def __normalize_query_string(query):
                        for s in query.split('&')
                        if len(s) > 0)
 
-    normalized = '&'.join('%s=%s' % (p[0], p[1] if len(p) > 1 else '')
+    normalized = '&'.join('%s=%s' % (aws_url_encode(p[0]), aws_url_encode(p[1]) if len(p) > 1 else '')
                           for p in sorted(parameter_pairs))
     return normalized
 
 
+def aws_url_encode(text):
+    """
+    URI-encode each parameter name and value according to the following rules:
+    - Do not URI-encode any of the unreserved characters that RFC 3986 defines: A-Z, a-z, 0-9, hyphen (-),
+      underscore (_), period (.), and tilde (~).
+    - Percent-encode all other characters with %XY, where X and Y are hexadecimal characters (0-9 and uppercase A-F).
+      For example, the space character must be encoded as %20 (not using '+', as some encoding schemes do) and
+      extended UTF-8 characters must be in the form %XY%ZA%BC.
+    - Double-encode any equals (=) characters in parameter values.
+    """
+    return quote(text, safe='~=').replace('=', '==')
+
+
 def __now():
     return datetime.datetime.utcnow()
 

diff --git a/tests/stages_test.py b/tests/stages_test.py
index 1f42d11..26ac703 100644
--- a/tests/stages_test.py
+++ b/tests/stages_test.py
@@ -45,6 +45,33 @@ class TestStages(TestCase):
                          "e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855")
         self.assertEqual(signed_headers, "host;x-amz-date")
 
+    def test_task_1_create_a_canonical_request_url_encode_querystring(self):
+        """
+        Test that canonical requests correctly sort and url encode querystring parameters.
+        """
+        canonical_request, payload_hash, signed_headers = task_1_create_a_canonical_request(
+            query="arg1=true&arg3=c,b,a&arg2=false&noEncoding=ABC-abc_1.23~tilde/slash",
+            headers="{'Content-Type': 'application/json', 'Accept': 'application/xml'}",
+            port=None,
+            host="my-gateway-id.execute-api.us-east-1.amazonaws.com",
+            amzdate="20190921T022008Z",
+            method="GET",
+            data="",
+            security_token=None,
+            data_binary=False,
+            canonical_uri="/stage/my-path")
+        self.assertEqual(canonical_request, "GET\n"
+                         "/stage/my-path\n"
+                         "arg1=true&arg2=false&arg3=c%2Cb%2Ca&noEncoding=ABC-abc_1.23~tilde%2Fslash\n"
+                         "host:my-gateway-id.execute-api.us-east-1.amazonaws.com\n"
+                         "x-amz-date:20190921T022008Z\n"
+                         "\n"
+                         "host;x-amz-date\n"
+                         "e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855")
+        self.assertEqual(payload_hash,
+                         "e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855")
+        self.assertEqual(signed_headers, "host;x-amz-date")
+
     def test_task_2_create_the_string_to_sign(self):
         """
         Test the next function that is creating a string in exactly the same way as AWS is on the
diff --git a/tests/unit_test.py b/tests/unit_test.py
index dd06bf1..38b96ae 100755
--- a/tests/unit_test.py
+++ b/tests/unit_test.py
@@ -2,14 +2,13 @@
 # -*- coding: UTF-8 -*-
 
 import datetime
-import logging
 import sys
 
 from unittest import TestCase
 
 from mock import patch
 
-from awscurl.awscurl import make_request
+from awscurl.awscurl import aws_url_encode, make_request
 
 from requests.exceptions import SSLError
 from requests import Response
@@ -318,3 +317,13 @@ class TestRequestResponse(TestCase):
         self.assertFalse(expected in str(r.text.encode('utf-8')))
 
     pass
+
+class TestAwsUrlEncode(TestCase):
+  def test_aws_url_encode(self):
+    self.assertEqual(aws_url_encode(""), "")
+    self.assertEqual(aws_url_encode("AZaz09-_.~"), "AZaz09-_.~")
+    self.assertEqual(aws_url_encode(" /:@[`{"), "%20%2F%3A%40%5B%60%7B")
+    self.assertEqual(aws_url_encode("a=,=b"), "a==%2C==b")
+    self.assertEqual(aws_url_encode("\u0394-\u30a1"), "%CE%94-%E3%82%A1")
+
+  pass

Commas in querystring are not URL encoded
I've been using awscurl to call API Gateway endpoints, and it has been working great for us up until now (thanks very much for making this!).

I recently started working on an endpoint that takes comma-delimited arrays, and found that the signature is not working properly in this case.

Example failure:

```
$ awscurl -v https://my-gateway-id.execute-api.us-east-1.amazonaws.com/live/my-path?arg=a,b,c
...
('\n'
 'CANONICAL REQUEST = GET\n'
 '/live/my-path\n'
 'arg=a,b,c\n'
 'host:my-gateway-id.execute-api.us-east-1.amazonaws.com\n'
 'x-amz-date:20211202T033321Z\n'
 'x-amz-security-token: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\n'
 '\n'
 'host;x-amz-date;x-amz-security-token\n'
 'e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855')
...
{"message":"The request signature we calculated does not match the signature you provided. Check your AWS Secret Access Key and signing method. Consult the service documentation for details.\n\nThe Canonical String for this request should have been\n'GET\n/live/my-path\narg=a%2Cb%2Cc\nhost:my-gateway-id.execute-api.us-east-1.amazonaws.com\nx-amz-date:20211202T033321Z\nx-amz-security-token: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\n\nhost;x-amz-date;x-amz-security-token\ne3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855'\n\nThe String-to-Sign should have been\n'AWS4-HMAC-SHA256\n20211202T033321Z\n20211202/us-east-1/execute-api/aws4_request\n38b3266af08b8f9f119ffed742e0063da244001dbdf2331c42f4f1af695e3e64'\n"}
```

Reviewing [sigv4-create-canonical-request.html](https://docs.aws.amazon.com/general/latest/gr/sigv4-create-canonical-request.html), it says:
> Percent-encode all other characters with %XY, where X and Y are hexadecimal characters (0-9 and uppercase A-F). For example, the space character must be encoded as %20 (not using '+', as some encoding schemes do) and extended UTF-8 characters must be in the form %XY%ZA%BC.

In my case, I believe that means it should be sending `arg=a%2Cb%2Cc` instead of `arg=a,b,c`

Testing locally, the following patch appears to fix things for me, but I'm not sure how much fallout this might cause for other use cases:

```
diff --git a/awscurl/awscurl.py b/awscurl/awscurl.py
index cf09318..66a14c4 100755
--- a/awscurl/awscurl.py
+++ b/awscurl/awscurl.py
@@ -16,6 +16,7 @@ import configparser
 import configargparse
 import requests
 from requests.structures import CaseInsensitiveDict
+from urllib.parse import urlencode


 from .utils import sha256_hash, sha256_hash_for_binary_data, sign
@@ -315,9 +316,9 @@ def __normalize_query_string(query):
                        for s in query.split('&')
                        if len(s) > 0)

-    normalized = '&'.join('%s=%s' % (p[0], p[1] if len(p) > 1 else '')
-                          for p in sorted(parameter_pairs))
-    return normalized
+    normalized_pairs = [(p[0], p[1] if len(p) > 1 else '')
+                        for p in [p for p in sorted(parameter_pairs)]]
+    return urlencode(normalized_pairs)


 def __now():
```


tests/stages_test.py::TestStages::test_task_1_create_a_canonical_request tests/stages_test.py::TestStages::test_task_4_build_auth_headers_for_the_request tests/stages_test.py::TestStages::test_task_1_create_a_canonical_request_url_encode_querystring tests/stages_test.py::TestStages::test_task_3_calculate_the_signature tests/stages_test.py::TestStages::test_task_2_create_the_string_to_sign tests/unit_test.py::TestMakeRequestWithBinaryData::test_make_request tests/unit_test.py::TestMakeRequestWithToken::test_make_request tests/unit_test.py::TestMakeRequest::test_make_request tests/unit_test.py::TestAwsUrlEncode::test_aws_url_encode tests/unit_test.py::TestMakeRequestVerifySSLPass::test_make_request tests/unit_test.py::TestHostFromHeaderUsedInCanonicalHeader::test_make_request tests/unit_test.py::TestMakeRequestVerifySSLRaises::test_make_request tests/unit_test.py::TestRequestResponse::test_make_request tests/unit_test.py::TestMakeRequestWithTokenAndBinaryData::test_make_request