diff --git a/lib/aws/s3/authentication.rb b/lib/aws/s3/authentication.rb
index 47089a9..0307c80 100644
--- a/lib/aws/s3/authentication.rb
+++ b/lib/aws/s3/authentication.rb
@@ -68,7 +68,8 @@ def canonical_string
           memoized :canonical_string
 
           def encoded_canonical
-            digest   = OpenSSL::Digest::Digest.new('sha1')
+            klass    = OpenSSL::Digest.respond_to?(:new) ? OpenSSL::Digest : OpenSSL::Digest::Digest
+            digest   = klass.new('sha1')
             b64_hmac = [OpenSSL::HMAC.digest(digest, secret_access_key, canonical_string)].pack("m").strip
             url_encode? ? CGI.escape(b64_hmac) : b64_hmac
           end