STEGANOGRAPYH FOR HIDING MESSAGE INTO MP3 FILE Joseph Dedy Irawan Informatics Engineering, Industrial Technology Faculty, Institut Teknologi Nasional Malang Jalan Raya Karangploso KM 2 Malang Email: joseph_dedy@yahoo.co.id ABSTRACT The advance communication data transfer today makes it need the support of high security level. In this case we can use steganography to hide a message or data that is difficult to detect into media or file. Today steganography has been developed in digital area applied in, for example audio file in MP3 file format. The steganography implementation on MP3 file is of huge potential to develop further. It is believed to be such perfect media to hide message. In this paper we discuss the process of stenographing without damaging or reducing the quality of the MP3 media. Keywords: Steganography, hide message, encryption, MP3 file. 1 INTRODUCTION Security of information in this era is a crucial necessity in various aspect of life. Information can be a very precious thing if it has something related to business, security and public decision, which is hunted by a lot of people on various purposes. Such information as a user name and a password, a bank account, etc. is very risky to send through internet or e-mail. It is common knowledge that MP3 file has been widely spread through internet. However people merely recognize MP3 file as an entertainment media. Such file is capable of becoming one of the media of steganography. Because of its common use, it is potential to minimize public suspicion toward the hidden information in the file. The use of steganography offers high security toward the important data by making it appear invisible. And the level of the security can be optimized by encrypting the original file prior to inserting the hidden message. 1.1 Problems of the Research How to avoid damaging the media file (MP3 file) for playback How to hide the message keep undetected by unauthorized people. How to decode and restore the hidden information without damaging the file 1.2 Objectives of the Research The objective of the research is to insert hidden message (text file) into MP3 file media. 1.3 Scope and Limitation Implementation of steganography on MPEG-1 layer III (MP3) The message inserted is a text file (*.txt) only 2 MODEL, ANALYSIS, DESIGN, AND IMPLEMENTATION The theory, design and implementation on the system of insert secret message into MP3 Files using steganography method will be described in the following sections. 2.1 Encryption Encryption is the process of transforming information (referred to as plaintext) using an algorithm (called cipher) to make it unreadable to anyone except those possessing special knowledge, usually referred to as a key. The result of the process is encrypted information (in cryptography, referred to as cipher text). In many contexts, the word encryption also implicitly refers to the reverse process, decryption (e.g. software for encryption can typically also perform decryption), to make the encrypted information readable again (i.e. to make it unencrypted). 317
318 The 5 th International Conference on Information & Communication Technology and Systems Encryption has long been used by militaries and governments to facilitate secret communication. Encryption is now used in protecting information within many kinds of civilian systems, such as computers, networks (e.g. the Internet e-commerce), mobile telephones, wireless microphones, wireless intercom systems, Bluetooth devices and bank automatic teller machines. Encryption is also used in digital rights management to prevent unauthorized use or reproduction of copyrighted material and in software also to protect against reverse engineering. Encryption, by itself, can protect the confidentiality of messages, but other techniques are still needed to protect the integrity and authenticity of a message; for example, verification of a message authentication code (MAC) or a digital signature. Standards and cryptographic software and hardware to perform encryption are widely available, but successfully using encryption to ensure security may be a challenging problem. A single slip-up in system design or execution can allow successful attacks. Sometimes an adversary can obtain unencrypted information without directly undoing the encryption. 2.2 Steganography Steganography is the art and science of writing hidden messages in such a way that no one apart from the sender and intended recipient even realizes there is a hidden message. By contrast, cryptography obscures the meaning of a message, but it does not conceal the fact that there is a message. Today, the term steganography includes the concealment of digital information within computer files. For example, the sender might start with an ordinary-looking image file, and then adjust the color of every 100th pixel to correspond to a letter in the alphabet -- a change so subtle that someone who isn't actively looking for it is unlikely to notice it. The word steganography is of Greek origin and means "covered, or hidden writing". Its ancient origins can be traced back to 440 BC. Herodotus mentions two examples of steganography in The Histories of Herodotus. Demaratus sent a warning about a forthcoming attack to Greece by writing it on a wooden panel and covering it in wax. Wax tablets were in common use then as re-usable writing surfaces, sometimes used for shorthand. Another ancient example is that of Histiaeus, who shaved the head of his most trusted slave and tattooed a message on it. After his hair had grown the message was hidden. The purpose was to instigate a revolt against the Persians. Later, Johannes Trithemius published the book Steganographia, a treatise on cryptography and steganography disguised. Generally, a steganographic message will appear to be something else: a picture, an article, a shopping list, or some other message. This apparent message is the cover text. For instance, a message may be hidden by using invisible ink between the visible lines of innocuous documents. The advantage of steganography over cryptography alone is that messages do not attract attention to themselves, to messengers, or to recipients. An unhidden coded message, no matter how unbreakable it is, will arouse suspicion and may in itself be incriminating, as in countries where encryption is illegal. Often, steganography and cryptography are used together to ensure security of the covert message. Steganography used in electronic communication include steganographic coding inside of a transport layer, such as a file, or a protocol, such as UDP. Usually, files meant for internet means are put into media types that are lossless, such as FLAC, WAV, and BMP and other file types. A steganographic message (the plaintext) is often first encrypted by some traditional means, producing a cipher text. Then, a cover text is modified in some way to contain the cipher text, resulting in stegotext. For example, the letter size, spacing, typeface, or other characteristics of a cover text can be manipulated to carry the hidden message; only the recipient (who must know the technique used) can recover the message and then decrypt it. Francis Bacon is known to have suggested such a technique to hide messages The objectives of hiding the information cover robustness, undetectability, invisibility, security, complexity, dan capacity. They cannot be achieved at once. For example, if we intend to hide a huge file in a medium, we cannot obtain maximum level of security and sustainability. Secure steganography Capacity Naive steganography Copyright marking Undetectability Figure 1. Trade-off Data hiding Robustness
B46 - Steganograpyh For Hiding Message Into MP3 File - Joseph Dedy I 319 Every hiding technique consist of algorithm for embedding process and the detection. Embedding algorithm is used to hide the secret message into a cover object (carrier/medium). A stegno key is used to protect the embedding process in order to be recognized or access by the person who knows the key only. Detector algorithm is used on a suspected object containing hidden message in it (stegno-object or marked-object). Secret Message Secret Message Digital Object Carrier Embbeding Algorithm Transmission via Network Detector Algorithm Stego Key Stego Key Figure 3. General model of data hiding 3 RESULT To illustrate the step by step process of inserting the hidden message into MP3 file, we can see to the flowchart (figure 2). Figure 4. Opening MP3 File First open the selected MP3 file, and click check MP3 button to check whether the file can be inserted with a hidden message or not, that is then displayed in the same dialog box. Figure 2. Flowchart
320 The 5 th International Conference on Information & Communication Technology and Systems Figure 5. Message to be inserted By using notepad, create a message to be inserted into the MP3 file and save the file with txt extention. Figure 8. Opening Message To unpack the inserted file, open it by clicking browse button. After selecting the MP3 with hidden message in it, enter the password to decode the incription press the Buka pesan Button on the bottom right. When succsesfull, the information box clarifing opening the hidden file will appear. Figure 6. Inserting Process Locate the file to be inserted by clicking the Browse Mp3 button, the program will automatically calculate the posible capacity of MP3 file to be inserted with the txt file. Next, enter the password for encryption procces. by clicking Sisipkan pesan button the file will be compressed and increpted with the password as increaption key, then the can be inserted into MP3 file. When succsesfull the information box (figure 6) will appear. Figure 9. Message to be inserted When yes is click, the hidden message is displayed on notepad. Figure 10. Message to be inserted Figure 7. inserted successful By using Winhex software, we can see the deference between the two MP3 files, before and after inserted with hiding message, as show in figure 11 and 12.
B46 - Steganograpyh For Hiding Message Into MP3 File - Joseph Dedy I 321 Figure 11. Before Inserted with Hidden Message Figure 12. After Inserted with Hidden Message
322 The 5 th International Conference on Information & Communication Technology and Systems 4 CONCLUSION AND DISCUSSION 4.1. Conclusion On higher bit rate MP3 files are likely to have a higher capacity to hide message. The successful inserting process is indicated by the same sound quality of both the original and the outcome The decoded file has the same content as the original one (undamaged) 4.2. Suggestion For optimum security, it is suggested that the password used to encrypt the message be saved in a secure place. It is necessary to develop further about the MP3 frame reading to avoid crashing application due to numerous frames to read. REFERENCES [1] Network Associates, Inc., (1999) An Introduction to Cryptography [2] N. Johnson and S. Jajodia. (1998) Exploring steganography: seeing the unseen. IEEE Computer, pages 26.34, 1998 [3] David Kahn (1996) The Code breakers [4] Provos, N. and Honeyman (2002) Detecting Steganographic Content on the Internet. Internet Society Symposium on Network and Distributed System Security, San Diego [5] Whitfield Diffie and Susan Eva Landau, Privacy on the Line, MIT Press [6] David Kahn (1996) The Code breakers published a revised edition. [7] N. Johnson and S. Jajodia (1998) Exploring steganography: seeing the unseen. IEEE Computer, pp. 26.34.