<?php
 
$re = "/Content-Transfer-Encoding:\\sbase64\\s+(.*)(?=Content-Transfer-Encoding: base64|$)/"; 
$str = "Content-Transfer-Encoding: base64\n\nDQoNCg0KDQoNCg0KDQoNCg0KDQpbQiZRXTxodHRwOi8vd3d3LmRpeS5jb20+DQoNCg0KDQoNCg0K W2h0dHA6Ly9raW5nZmlzaGVyLnNjZW5lNy5jb20vaXMvaW1hZ2UvS2luZ2Zpc2hlci9pY29uX3N0 b3JlX2xvY2F0b3I/d2lkPTM2JmhlaT0zNiZxbHQ9MTAwXTxodHRwOi8vd3d3LmRpeS5jb20vZmlu ZC1hLXN0b3JlPg0KDQoNCg0KRmluZCBhIHN0b3JlPGh0dHA6Ly93d3cuZGl5LmNvbS9maW5kLWEt c3RvcmU+DQoNCg0KDQoNCkN1c3RvbWVyIFNlcnZpY2VzDQoNCjAzMzMgMDE0IDMzNTcNCg0KDQoN Cg0KDQoNCg0KDQoNCkluc3BpcmF0aW9uPGh0dHA6Ly93d3cuZGl5LmNvbS9pbnNwaXJhdGlvbi8w Lmlyb290Pg0KDQpQcm9qZWN0czxodHRwOi8vd3d3LmRpeS5jb20vcHJvamVjdHMvMi5wcm9vdD4N Cg0KU2hvcDxodHRwOi8vd3d3LmRpeS5jb20vc2hvcC8+DQoNCkhlbHAgJiBBZHZpY2U8aHR0cDov L3d3dy5kaXkuY29tL2hlbHAtYWR2aWNlLzEuaHJvb3Q+DQoNCk15IGFjY291bnQ8aHR0cDovL3d3 dy5kaXkuY29tL2N1c3RvbWVyL215X2FjY291bnQvPg0KDQoNCg0KDQoNCg0KDQoNCg0KRGVhciBC ZW4gUGF0b24NCg0KDQoNCg0KVGhhbmsgeW91IGZvciB5b3VyIG9yZGVyDQoNCg0KDQoNCg0KT3Jk ZXIgbnVtYmVyOg0KDQowMDYzMTA5MDU1DQoNCg0KDQpUb3RhbCBDb3N0Og0KDQrCozMuMjcNCg0K DQoNClRoYW5rIHlvdSBmb3Igb3JkZXJpbmcgZnJvbSBCJlEuIFlvdeKAmWxsIGZpbmQgZGV0YWls cyBvZiB5b3VyIG9yZGVyIGFuZCBkZWxpdmVyeSBvciBjb2xsZWN0aW9uIGluZm9ybWF0aW9uIGJl bG93LiBGb3IgaGVscCB3aXRoIHF1ZXN0aW9ucyBhYm91dCBvdXIgc2VydmljZSwgcGxlYXNlIHNl--_000_D16F6E4A2986D34F9D752E3564EAC46F51043449APP1198ghakfplc_ Content-Type: text/html; charset=\"utf-8\" Content-Transfer-Encoding: base64\n\nPGh0bWwgeG1sbnM6dj0idXJuOnNjaGVtYXMtbWljcm9zb2Z0LWNvbTp2bWwiIHhtbG5zOm89InVy bjpzY2hlbWFzLW1pY3Jvc29mdC1jb206b2ZmaWNlOm9mZmljZSIgeG1sbnM6dz0idXJuOnNjaGVt YXMtbWljcm9zb2Z0LWNvbTpvZmZpY2U6d29yZCIgeG1sbnM6bT0iaHR0cDovL3NjaGVtYXMubWlj cm9zb2Z0LmNvbS9vZmZpY2UvMjAwNC8xMi9vbW1sIiB4bWxucz0iaHR0cDovL3d3dy53My5vcmcv\n"; 
 
preg_match_all($re, $str, $matches);
 
print_r($matches[1]);

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