Handling the explosion of massive data not only requires significant improvements in information processing, storage and communication abilities of hardware but also demands higher security in the storage and communication of sensitive information. As a type of hardware-based security primitives, physically unclonable functions (PUFs) represent a promising emerging technology utilizing random imperfections existing in a physical entity, which cannot be predicted or cloned. However, if a PUF is exploited to carry out secure communication, the keys inside it must be written into non-volatile memory and then shared with other participants that do not hold the PUF, which makes the keys vulnerable. Here, we show that identical PUFs, e.g. twin PUFs can be fabricated on the same aligned carbon nanotube arrays and optimized to yield excellent uniformity, uniqueness, randomness, and reliability. The twin PUFs show a good consistency of approximately 95 % and are used to demonstrate secure communication with a bit error rate reduced to one trillion through a fault-tolerant design. As a result, our twin PUFs offering a convenient, low-cost and reliable new technology for guarantee information exchange security.