diff --git a/phpseclib/Net/SFTP.php b/phpseclib/Net/SFTP.php
index fec75556..2009681f 100644
--- a/phpseclib/Net/SFTP.php
+++ b/phpseclib/Net/SFTP.php
@@ -2479,9 +2479,7 @@ class Net_SFTP extends Net_SSH2
                     // IEEE 754 binary64 "double precision" on such platforms and
                     // as such can represent integers of at least 2^50 without loss
                     // of precision. Interpreted in filesize, 2^50 bytes = 1024 TiB.
-                    extract(unpack('Nupper/Nsize', $this->_string_shift($response, 8)));
-                    $attr['size'] = $upper ? 4294967296 * $upper : 0;
-                    $attr['size']+= $size < 0 ? ($size & 0x7FFFFFFF) + 0x80000000 : $size;
+                    $attr['size'] = hexdec(bin2hex($this->_string_shift($response, 8)));
                     break;
                 case NET_SFTP_ATTR_UIDGID: // 0x00000002 (SFTPv3 only)
                     $attr+= unpack('Nuid/Ngid', $this->_string_shift($response, 8));