diff --git a/spec/std/http/cookie_spec.cr b/spec/std/http/cookie_spec.cr
index 28174021f908..08d2e91c7b16 100644
--- a/spec/std/http/cookie_spec.cr
+++ b/spec/std/http/cookie_spec.cr
@@ -38,34 +38,33 @@ module HTTP
         expect_raises IO::Error, "Invalid cookie name" do
           HTTP::Cookie.new("\t", "")
         end
-        # more extensive specs on #name=
       end
 
       it "raises on invalid value" do
         expect_raises IO::Error, "Invalid cookie value" do
           HTTP::Cookie.new("x", %(foo\rbar))
         end
-        # more extensive specs on #value=
       end
     end
 
     describe "#name=" do
       it "raises on invalid name" do
         cookie = HTTP::Cookie.new("x", "")
-        expect_raises IO::Error, "Invalid cookie name" do
-          cookie.name = ""
-        end
-        expect_raises IO::Error, "Invalid cookie name" do
-          cookie.name = "\t"
-        end
-        expect_raises IO::Error, "Invalid cookie name" do
-          cookie.name = "\r"
-        end
-        expect_raises IO::Error, "Invalid cookie name" do
-          cookie.name = "a\nb"
-        end
-        expect_raises IO::Error, "Invalid cookie name" do
-          cookie.name = "a\rb"
+        invalid_names = [
+          '"', '(', ')', ',', '/',
+          ' ', '\r', '\t', '\n',
+          '{', '}',
+          (':'..'@').each,
+          ('['..']').each,
+        ].flat_map { |c| "a#{c}b" }
+
+        # name cannot be empty
+        invalid_names << ""
+
+        invalid_names.each do |invalid_name|
+          expect_raises IO::Error, "Invalid cookie name" do
+            cookie.name = invalid_name
+          end
         end
       end
     end
@@ -73,26 +72,15 @@ module HTTP
     describe "#value=" do
       it "raises on invalid value" do
         cookie = HTTP::Cookie.new("x", "")
-        expect_raises IO::Error, "Invalid cookie value" do
-          cookie.value = %(foo\rbar)
-        end
-        expect_raises IO::Error, "Invalid cookie value" do
-          cookie.value = %(foo"bar)
-        end
-        expect_raises IO::Error, "Invalid cookie value" do
-          cookie.value = "foo;bar"
-        end
-        expect_raises IO::Error, "Invalid cookie value" do
-          cookie.value = "foo\\bar"
-        end
-        expect_raises IO::Error, "Invalid cookie value" do
-          cookie.value = "foo\\bar"
-        end
-        expect_raises IO::Error, "Invalid cookie value" do
-          cookie.value = "foo bar"
-        end
-        expect_raises IO::Error, "Invalid cookie value" do
-          cookie.value = "foo,bar"
+        invalid_values = {
+          '"', ',', ';', '\\',   # invalid printable ascii characters
+          ' ', '\r', '\t', '\n', # non-printable ascii characters
+        }.map { |c| "foo#{c}bar" }
+
+        invalid_values.each do |invalid_value|
+          expect_raises IO::Error, "Invalid cookie value" do
+            cookie.value = invalid_value
+          end
         end
       end
     end
diff --git a/src/base64.cr b/src/base64.cr
index 2457768daa00..ddb783dfe49e 100644
--- a/src/base64.cr
+++ b/src/base64.cr
@@ -262,7 +262,7 @@ module Base64
       break if bytes > fin
 
       # Move the pointer by one byte until there is a valid base64 character
-      while bytes.value == NL || bytes.value == NR
+      while bytes.value.in?(NL, NR)
         bytes += 1
       end
       break if bytes > fin
@@ -272,7 +272,7 @@ module Base64
     end
 
     # Move the pointer by one byte until there is a valid base64 character or the end of `bytes` was reached
-    while (bytes < fin + 4) && (bytes.value == NL || bytes.value == NR)
+    while (bytes < fin + 4) && bytes.value.in?(NL, NR)
       bytes += 1
     end
 
diff --git a/src/http/cookie.cr b/src/http/cookie.cr
index d22fdf1419d0..9dc5517fa05d 100644
--- a/src/http/cookie.cr
+++ b/src/http/cookie.cr
@@ -58,7 +58,11 @@ module HTTP
         # valid characters for cookie-name per https://tools.ietf.org/html/rfc6265#section-4.1.1
         # and https://tools.ietf.org/html/rfc2616#section-2.2
         # "!#$%&'*+-.0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ^_`abcdefghijklmnopqrstuvwxyz|~"
-        unless (0x21...0x7f).includes?(byte) && byte != 0x22 && byte != 0x28 && byte != 0x29 && byte != 0x2c && byte != 0x2f && !(0x3a..0x40).includes?(byte) && !(0x5b..0x5d).includes?(byte) && byte != 0x7b && byte != 0x7d
+        if !byte.in?(0x21...0x7f) ||                 # Non-printable ASCII character
+           byte.in?(0x22, 0x28, 0x29, 0x2c, 0x2f) || # '"', '(', ')', ',', '/'
+           byte.in?(0x3a..0x40) ||                   # ':', ';', '<', '=', '>', '?', '@'
+           byte.in?(0x5b..0x5d) ||                   # '[', '\\', ']'
+           byte.in?(0x7b, 0x7d)                      # '{', '}'
           raise IO::Error.new("Invalid cookie name")
         end
       end
@@ -76,7 +80,7 @@ module HTTP
       value.each_byte do |byte|
         # valid characters for cookie-value per https://tools.ietf.org/html/rfc6265#section-4.1.1
         # all printable ASCII characters except ' ', ',', '"', ';' and '\\'
-        unless (0x21...0x7f).includes?(byte) && byte != 0x22 && byte != 0x2c && byte != 0x3b && byte != 0x5c
+        if !byte.in?(0x21...0x7f) || byte.in?(0x22, 0x2c, 0x3b, 0x5c)
           raise IO::Error.new("Invalid cookie value")
         end
       end