Encryption Techniques and Algorithms

Running head: ENCRYPTION TECHNIQUES AND ALGORITHMS
Encryption Techniques and Algorithms
Name of the Student
Name of the University
Author Note

ENCRYPTION TECHNIQUES AND ALGORITHMS
1
Question 1
a) With the aid of diagram, describe the proposed solutions for the above
scenario. For each solution, provide ONE (1) advantage and ONE (1)
disadvantage.
The cryptographic solutions identified for transferring class 1 data in classified mode to
respective branch offices of the company twice a day are Message Digest algorithm MD5 and
Secure Hash Algorithm (SHA).
Message Digest refers to a hash function involving one way cryptography and accepts
messages of all lengths and returns fixed length digest values as output for authenticating the
source text using 128-bit hash values (Ardy et al., 2017). Being quite a long serving
encryption technique, it is known consist of a substantial set of vulnerabilities. It is still used
today for purposes like verifying integrity of data as also to be used as checksum.
A B C D
Mi
Ki
A B C D
F+
+
+
<<<s
+

ENCRYPTION TECHNIQUES AND ALGORITHMS
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Figure 1: MD5 operation
The above diagram represents one of the 64 MD5 operations present in four different
rounds each which has 16 number of operations. Here, F denotes nonlinear functions and one
of these functions get used in every round. The variable Mi points to input messages of 32 bit
block sizes input messages while Ki is the constant and <<<s refers to the rotation towards
the left of bits by s places. Both Ki and <<<s differs with every operation.
Advantage: It is faster to compute 128 bit digests in md5 than 160 bit digests and above in
SHA. As MD5 already excels in purposes other than cryptography, the speed benefit that
MD5 provides makes it the preferred choice.
Disadvantage: The cryptographic algorithm MD5 is reportedly vulnerable to hash collision.
The weakness enables attackers in creating various different input sources which, when
the MD5 algorithm is in use, results in the output of the same fingerprint.
SHA or Secure Hash Algorithm refers to the group of cryptographic hashing
techniques that take inputs and produce 160 bit long (20 bytes) hash values called message
digest and typically gets rendered as hexadecimal numbers of length 40 digits.
A B C D E
Wt
Kt
F +
<<<s +
<<<30
+
+

ENCRYPTION TECHNIQUES AND ALGORITHMS
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A B C D E
Figure 2: SHA operation
This presents one operation of the SHA hashing technique. Here A, B, C, D, E are 32
bit words of the state. <<<s is the left circular shift, Wt the message input and Kt is the
constant with <<<s and Kt varying for every iteration.
Advantage: The higher bit sized hashing provides tighter security as it becomes difficult to
crack these codes because the process requires greater number of combinations. It is
important to note that in cryptographic hashing algorithms every hash generated is a unique
one.
Disadvantage: Compared to MD5, SHA techniques are slower to process because of using
160bit or higher hash values (Canteaut, A. 2016). As a result SHA is generally not used in
non-cryptographic tasks.