  Reversible Data Hiding in Encrypted Domain (RDHED) is an innovative method
that can keep cover information secret and allows the data hider to insert
additional information into it. This article presents a novel data hiding
technique in an encrypted text called Reversible Data Hiding in Encrypted Text
(RDHET). Initially, the original text is converted into their ASCII values.
After that, the Paillier cryptosystem is adopted to encrypt all ASCII values of
the original text and send it to the data hider for further processing. At the
data hiding phase, the secret data are embedded into homomorphically encrypted
text using a technique that does not lose any information, i.e., the
homomorphic properties of the Paillier cryptosystem. Finally, the embedded
secret data and the original text are recovered at the receiving end without
any loss. Experimental results show that the proposed scheme is vital in the
context of encrypted text processing at cloud-based services. Moreover, the
scheme works well, especially for the embedding phase, text recovery, and
performance on different security key sizes.
