I also search for open research code for hiding data. Pls, tell me if you know anything.

Open source code

search for "No Stega" called noise less steganography - a cover generation where the author hide data in multiple choice question & answer. (PhD thesis may be accessed through proquest)

Lingyun Xiang, Xingming Sun, Yuling Liu and Hengfu Yang, A Secure Steganographic Method via Multiple Choice Questions, Information Technology Journal, 10(5) (2011) 992–1000.

Abdelrahman Desoky, Comprehensive linguistic steganography survey, International Journal of Information and Computer Security, 4(2) (2010)164–197.

Abdelrahman Desoky, Nostega: A Novel Noiseless Steganography Paradigm, Journal of Digital Forensic Practice, 2(3) (2008) 132–139.

Abdelrahman Desoky, Sumstega: summarisation-based steganography methodology, International Journal of Information and Computer Security, 4(3) 234–263.

Abdelrahman Desoky search for his PhD thesis.

Cheating text mechanisiom is a method to hide the data in the text

Cheatinng text approach can use for hiding data

Markup languages may hide your text easily by different logistics.

Text steganography through multiple choice questions, score boards, nul cyphers, character/ line space adjustment techniques etc are some of the popular text steganography schemes.

Article Text Steganography Using Compression and Random Number Generators