Data Encryption Based On Protein Synthesis - Nguyen Dang Binh

4.2 Decoding the Huffman code
In Huffman trees each symbol is a leaf which
results in that Huffman codes have prefix property.
In codes with prefix property, no codeword is the
prefix of any other codeword in the set. The
decoding is done by taking the root of the Huffman
tree and recording 0 if the left child is traversed and
1 if the right child is visited. By reaching a leaf that
symbol’s codeword is recovered.
5 Transmission encryption algorithms
In the section 3.3, we have stated that our second
encoding mechanism requires to be digitized. By
means of Huffman coding, the data could be
compressed and also encrypted for the second time.
With 4 alphabet letters, 256 states are arranged.
This results in the presence of maximum 256
different symbols and consequently the same
maximum number of leaves in each Huffman tree.
As all the possible states of arrangements of Amino
acids might not be used in the data being encrypted,
the number of leaves of each Huffman tree might be
fewer than 256.
Having constructed the Huffman tree, the output
of second method is used for the input of the tree
thus converting the arrays of alphabets into strings of
binary data. But the problem is, the Huffman
encoding tree should also be transmitted along with
the message, reducing the effectiveness of this
algorithm. One typical solution to the problem is to
encode symbols along with their frequencies using
RSA method and transmit them along with the
message. At the receiver’s end, Huffman tree could
be reconstructed from frequencies to decrypt the
message.
The alternative robust solution is to use the binary
image of the recipient’s fingerprint, or specifically the
binary image of his or her minutiae. In the process of
fingerprinting, minutiae are specific points in a finger
image which vary from person to person and also
from finger to finger. After fingerprinting, the number
and locations of minutiae for each finger is recorded
and a binary image is created from this information.
A binary image is defined as an image where each
pixel has 2 possible values, black or white. Therefore
each pixel can be stored in memory by one bit of
information which is 1 if it is black and 0 if it is white
[2].
When the Huffman tree is constructed for
a message, the symbols’ codeword are achieved
which are variable-length codes in a binary form.
Having the binary codeword of each symbol, in the
binary image of the recipient’s minutiae, the image
should be searched to find the adjacent pixels which
form each binary codeword. The addresses or
coordinates of the first set of pixels forming the
binary codeword of each symbol should be recorded
and transmitted along with the message [2, 1].
At the destination, for decrypting the message,
the intended recipient’s fingerprint should be used to
decode the message. The binary image of the
recipient’s minutiae is again used for achieving the
codeword of symbols. This is done by putting
together the information of pixels that their
addresses -or coordinates- are given for each
symbol’s codeword. As the minutiae of each finger of
each individual is likely to be unique, if adversaries
get access to the key, which is the symbols and their
codeword in terms of the recipient’s minutiae
information , it is nearly impossible for them to
decrypt the message as they do not have access to
the fingerprint of the recipient.
6 Conclusion and Future Works
In this paper, after a brief revision of protein
biosynthesis, we used it to introduce an encryption
mechanism with two coding schemes. We have also
taken the advantage of Huffman coding to further
strengthen our method and provide compatibility with
common communication medium. We are working
on other methods to generate keys rather than
minutiae of each finger. Besides, an extended
coding scheme supporting several data types is in
the center of attention.
Acknowledgments
We appreciate insightful instructions and
generous contributions of Dr.R.Gharib and
Mr.A.Abedini from whom we have learned a lot.
References
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