LSB Steganography and AES Encryption for Multiple PDF Documents

Security is one important issue regarding data and information today. Steganography along with cryptography is used to hide and secure information. It is already an established practice to put watermark and to secure a single document using encryption. However, for large information requiring multiple documents has not received any attention. Here a program which can do steganography to multiple PDF documents to increase its steganography capacity is proposed, it is named MPDFStego. One of the steganography technique chosen in this research is the Least Significant Bit (LSB). LSB technique can be applied to Portable Document Format (PDF) by making use of its Tj Operator. Secret text is encrypted using Advanced Encryption Standard with 128-bit key size in Cipher Block Chaining (CBC) mode before it is embedded into the PDF document(s). Recompression and decompression of the PDF document(s) are done outside MPDFStego, with the help of QPDF tool. Testing and evaluation show that the MPDFStego is capable of hiding the secret text into one or many PDF documents (s).