Combination Base64 Algorithm and EOF Technique for Steganography

The steganography process combines mathematics and computer science. Steganography consists of a set of methods and techniques to embed the data into another media so that the contents are unreadable to anyone who does not have the authority to read these data. The main objective of the use of base64 method is to convert any file in order to achieve privacy. This paper discusses a steganography and encoding method using base64, which is a set of encoding schemes that convert the same binary data to the form of a series of ASCII code. Also, the EoF technique is used to embed encoding text performed by Base64. As an example, for the mechanisms a file is used to represent the texts, and by using the two methods together will increase the security level for protecting the data, this research aims to secure many types of files in a particular media with a good security and not to damage the stored files and coverage media that used.


Introduction
Data [1] is crucial for maintaining the confidentiality of information, especially vital information [2] and can only be known by certain parties only and the information are transmitted through the public network [1], [3], [4], if the data is not secured enough it will be easily tapped by others and the content easily known by users who do not have the authority [1], [5], [6]. One way to secure data is using a steganography technique [7], [8]. Steganography is the art and science to hide secret messages in other media so that the existence of such secret messages is unknowable, steganography is concealed by covering up or hiding messages [9]- [11], hidden messages can be read or extract from a file by using a certain method in this paper EoF were a technique using for steganography and Base64 a method to convert any file to printable text before hidden to media.
Base64 is a coding schemes that encode binary data and translate into a base64 representation [12], [13]. End of File (EOF) technique is a method that works by inserting data at the end of the file [14]. Singh and Supriya [12] explains the encoding and decoding process with the base64 algorithm can be performed for all types of files by converting into pr intable text, M. Ramalingam [15] conducts research for steganography on video types using 2 different methods for doing steganography and cryptography process with good result, another research was perform by Nurdiyanto [16] by using Pixel Value Differencing a message will be hidden in pixel image but the result from this made a distortion in pixel, it can happen when insert a large file or a lot of message to be hidden. Hidden message in pixel in maybe a good one but it can distort pixel, one of reason why combine Base64 and EoF for hidden information.

Methodology
Base64 algorithm [17], [18] and EOF technique are implemented by using Visual Basic.Net 2015 programming language, the experiment process is done step by step for each file to embedded into various media, the first step is to change the binary of each file into the form of text encoding using the Base64 algorithm, the result of text encoding is inserted into the media used as cover by using EOF technique, for base64 procedure encoding and decoding can be seen in the following function: FileToBase64(ByVal xobject As object) Using ms As New MemoryStream() xobject.Save(ms, format) Dim objBytes As Byte() = ms.ToArray() Dim base64String As String = Convert.ToBase64String(objBytes) Return base64String End Using Base64ToFile(ByVal base64Code As String) Dim objBytes As Byte() = Convert.FromBase64String(base64Code) Dim ms As New MemoryStream(objbytes, 0, objBytes.Length) Dim tmpObject As Object= objbytes.FromStream(ms, True) Return tmpObject The above function is a process snippet code to get the base64 value of each object to be embedded, the procedure Base64 [12], [17] are like below: 1. Look for the binary code of each object 2. Convert binary number 8 bits to the ASCII code 3. Combine the last 8 bits to 24 bits. 4. Then, broke a 24 bit earlier to 6 bits. It will produce four fractions. 5. Each fragment is converted into a decimal value. 6. Lastly, make value the decimal value to an index to choose a character constituent of base64 and the maximum is 63 or 64 to the index. The index value of the base64 algorithm can be seen in the For example, Base64 algorithm encoding process performed on binary = 0100100101101110 0111010001100101011100100110111001100001011101000110100101101111011011100110000101 101100 using the above procedure obtained the following encoding results in table 2 below : The above functions make it possible to embed base64 encoding text into any file, so there is no limit how big the file size to be embedded to cover media.

Result and Discussion
Experiments with Base64 algorithms and EOF techniques are perform with various types of files to be embeded, table 3 below is the file information in the experiment. Table 3. file information. Table 3 shows the file name and size of the file to be inserted and also the size of media as the cover, the next process is to perform steganography the existing file, and the results as in table 4: Table 4. steganography results.

No
Media to be Secure Cover Media Each of file will convert into printable text using base64 method and then insert into a cover media with EOF method, the size of cover media will increase when text are embeded, based on experiment process any file type can be well hide using the EoF method.

Conclusion
An experiments for all types can be done as well, before EoF process a file will be convert into printable text by using Base64 method, the steganography process with EoF techniques can perform will with Base64 encoding text. Next improvement a Base64 and EoF method can combine with compression algorithm, so the encoding base64 result compress by an algortithm and then embed to file by using EoF.