A Presentation on Fletcher Checksum, CRC, Adler-32 & Hamming code. Discussing their strengths and weaknesses

1. A Presentation on Fletcher
Checksum, CRC, Adler-32 &
Hamming code. Discussing
their strengths and
weaknesses.
Presented By
Pranto Afrin
Roll-BFH2101017F

2. Introduction
In the realm of data integrity, understanding the robustness
and limitations of various algorithms is crucial. This analysis
focuses on the Fletcher Checksum, CRC, Adler-32, and
Hamming Code algorithms. By delving into their intricacies,
we aim to discern their strengths and weaknesses, shedding
light on their effectiveness in ensuring data integrity.

3. Fletcher’s Checksum
The Fletcher Checksum algorithm is a widely used method for
error detection in data transmission. It divides the data into
fixed-size blocks and calculates a checksum for each block. By
comparing the calculated checksum with the received
checksum, errors can be detected.

4. Fletcher Checksum:Strengths and Weaknesses
Strengths of Fletcher Checksum Algorithm:
❖ Error Detection: Detecting errors, particularly burst errors in data transmission .
❖ Simplicity: Straightforward and easy to implement.
❖ Efficiency: Suitable for resource constrained environments.
Weaknesses of Fletcher Checksum Algorithm:
❖ Only Detection No Correction:It cannot correct errors, only detect them, and is
vulnerable to specific types of errors like the swapping of adjacent bits.
❖ Order Matters: The first weakness of the simple checksum is that it is insensitive to the
order of the blocks (bytes) in the data word (message). If the order is changed, the
checksum value will be the same and the change will not be detected.
❖ Small Checksum: The second weakness is that the universe of checksum values is small,
being equal to the chosen modulus.

5. CRC Algorithm
The Cyclic Redundancy Check (CRC) algorithm is widely used in various applications due
to its robustness and error detection capabilities. It computes a checksum that is
appended to the data, allowing the receiver to verify the integrity of the transmitted
data. The CRC algorithm can detect a range of errors, making it a preferred choice for
critical data transmission and storage systems.

6. CRC Algorithm:Strengths and Weaknesses
Strengths of CRC Algorithm:
❖ Detecting Error: The CRC algorithm’s robustness lies in its ability to detect multiple
errors within a data stream. It can handle burst errors, random errors, thereby ensuring
reliable data transmission and storage.
❖ Widely Used: Used in communication protocols.It can be implemented in hardware or
software.
❖ Low Overhead: Low overhead compared to other error-checking techniques.
Weaknesses of CRC Algorithm:
❖ Limited Error Detection: CRC algorithm has limitations, especially in detecting certain
types of errors, such as those occurring in overlapping bit positions.
❖ Only Detection No Correction:It cannot correct errors, only detect them.

7. Adler-32 Algorithm
The Adler-32 algorithm, unlike CRC, is a checksum algorithm that focuses solely on error
detection. It is faster and requires less computational resources than CRC.Adler-32 is a
simple and fast algorithm that generates a 32-bit checksum which is computed by
dividing the data into blocks and processing each block in a streaming fashion.

8. Adler-32 Algorithm:Strengths and Weaknesses
Strengths of Adler-32 Algorithm:
❖ Robust:The Adler-32 algorithm provides a moderate level of robustness for error
detection.
❖ Less Resource Required:It is faster and requires fewer computational resources
than CRC
❖ Streaming Processing: Process data in a streaming fashion.
Weaknesses of Adler-32 Algorithm:
❖ No Error Correction:While the Adler-32 algorithm is efficient for error detection,
it has some limitations. It does not provide error correction capabilities, meaning it
can only detect errors but not fix them.
❖ Specific: Additionally, the Adler-32 algorithm is susceptible to certain types of
systematic errors, such as those caused by network fluctuations or data
corruption. Therefore, it is important to consider these limitations when deciding
whether to implement the Adler-32 algorithm for error detection in specific
applications

9. Hamming Code
Hamming code is an error detection and correction system that can detect and correct
errors when data is stored or transmitted..It uses a block parity mechanism. The data
is divided into blocks, and parity is added to the block. It can correct single-bit errors
and detect the presence of two-bit errors in a data block.

10. Hamming Code:Strengths and Weaknesses
Strengths of Hamming Code:
❖ Error Detection and Correction: Ability to both detect and correct errors in
transmitted data
❖ Efficiency: Efficient in terms of the number of redundant bits it adds to the
original data.
❖ Simple Implementation: Implemented using simple bitwise operations. ❑ Single-
Error Correction: designed to correct single-bit errors.
Weaknesses of Hamming Code:
❖ Limited Error Correction Capability: Effective for only correcting single-bit errors.
❖ Redundancy Overhead: Adds some redundancy to the transmitted data.
❖ Limited Range of Applicability: Well suited for applications where single-bit
errors are common
❖ Fixed Block Size: Operates on fixed-size blocks of data.

11. Comparison Chart
Technique Fletcher
Checksum
CRC Adler-32 Hamming
Code
Type Error detection Error detection Error checking and
checksum
Error detection and
correction
Purpose Detect errors in data Detect errors in data Detect errors in data Detect and correct
errors
Algorithm Basis Modular arithmetic Polynomial division Addition and bitwise
XOR
Linear block code
Method of Operation Summation of data
blocks
Division and
remainder
Rolling checksum Bit-level parity
calculation
Strengths Simple and fast Widely used, strong
error detection
Fast, suitable for
streaming data
Capable of error
correction
Weaknesses Limited error
detection capability
Vulnerable to burst
errors
Limited collision
resistance
Increased redundancy
for correction
Use Cases Small-scale
applications
Network
communication
File integrity checks Memory storage and
transmission
Collision Resistance Not designed for this
purpose
Used in some CRC
variants
Not designed for this
purpose
Not applicable

12. Conclusion
After analyzing the strengths and weaknesses of Fletcher Checksum, CRC, Adler-32, and
Hamming Code, it is clear that each technique has its own unique advantages and
limitations. Depending on the specific requirements of the system and the level of error
detection needed, one technique may be more suitable than others. It is crucial to
thoroughly evaluate and carefully choose the appropriate error detection technique for
each application to ensure reliable and accurate data transmission.

13. Thank You