PPT: Coding-Decoding | General Intelligence and Reasoning for SSC CGL PDF Download

 Page 1


Coding and 
Decoding
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Coding and 
Decoding
What is 'Coding-
Decoding'?
Encryption
Coding is a method of 
transmitting data 
between sender and 
receiver in an encrypted 
manner, preventing 
unauthorised access to 
the information during 
transmission.
Protection
The process helps protect 
sensitive information 
from being corrupted or 
leaked, ensuring data 
integrity throughout the 
communication channel.
Decryption
Once encrypted data reaches its destination, the receiver 
decodes it according to pre-established rules to obtain the 
original information in its unaltered form.
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Coding and 
Decoding
What is 'Coding-
Decoding'?
Encryption
Coding is a method of 
transmitting data 
between sender and 
receiver in an encrypted 
manner, preventing 
unauthorised access to 
the information during 
transmission.
Protection
The process helps protect 
sensitive information 
from being corrupted or 
leaked, ensuring data 
integrity throughout the 
communication channel.
Decryption
Once encrypted data reaches its destination, the receiver 
decodes it according to pre-established rules to obtain the 
original information in its unaltered form.
Types of Coding Decoding Questions
1
Letter Coding
In this type, alphabets in a 
word are replaced by 
other alphabets according 
to specific rules. Success 
in these questions 
requires knowing the 
positional values of all 
alphabetical letters in 
both forward and 
backward order.
2
Substitution Coding
These questions involve 
replacing words with 
different words according 
to a given pattern. Careful 
tracking of the 
substitution chain is 
essential to arrive at the 
correct solution.
3
Mixed Letter Coding
This type presents 
phrases in coded language 
where you must identify 
the code for a specific 
word by finding common 
elements across multiple 
coded phrases.
Page 4


Coding and 
Decoding
What is 'Coding-
Decoding'?
Encryption
Coding is a method of 
transmitting data 
between sender and 
receiver in an encrypted 
manner, preventing 
unauthorised access to 
the information during 
transmission.
Protection
The process helps protect 
sensitive information 
from being corrupted or 
leaked, ensuring data 
integrity throughout the 
communication channel.
Decryption
Once encrypted data reaches its destination, the receiver 
decodes it according to pre-established rules to obtain the 
original information in its unaltered form.
Types of Coding Decoding Questions
1
Letter Coding
In this type, alphabets in a 
word are replaced by 
other alphabets according 
to specific rules. Success 
in these questions 
requires knowing the 
positional values of all 
alphabetical letters in 
both forward and 
backward order.
2
Substitution Coding
These questions involve 
replacing words with 
different words according 
to a given pattern. Careful 
tracking of the 
substitution chain is 
essential to arrive at the 
correct solution.
3
Mixed Letter Coding
This type presents 
phrases in coded language 
where you must identify 
the code for a specific 
word by finding common 
elements across multiple 
coded phrases.
Letter Coding: Solving Techniques
Backward Direction 
Values
Understanding the positional 
values of alphabets in reverse 
order (Z=1, Y=2, etc.) is crucial 
for many letter coding 
questions. Memorising these 
positions saves valuable time 
during exams.
Pattern Recognition
Analyze the pattern by 
comparing corresponding 
letters in the original word and 
its code. Look for consistent 
shifts in alphabet positions, 
such as +2/-2 alternating 
pattern shown in the PARKING 
³ RYTIKLI example.
Sample Solution
In the example where 
"PARKING" becomes 
"RYTIKLI" through alternating 
+2/-2 shifts, we can apply the 
same pattern to decode 
"FLOWERS" as "HJQUHPQ" by 
systematically applying the 
alternating shifts to each letter.
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Coding and 
Decoding
What is 'Coding-
Decoding'?
Encryption
Coding is a method of 
transmitting data 
between sender and 
receiver in an encrypted 
manner, preventing 
unauthorised access to 
the information during 
transmission.
Protection
The process helps protect 
sensitive information 
from being corrupted or 
leaked, ensuring data 
integrity throughout the 
communication channel.
Decryption
Once encrypted data reaches its destination, the receiver 
decodes it according to pre-established rules to obtain the 
original information in its unaltered form.
Types of Coding Decoding Questions
1
Letter Coding
In this type, alphabets in a 
word are replaced by 
other alphabets according 
to specific rules. Success 
in these questions 
requires knowing the 
positional values of all 
alphabetical letters in 
both forward and 
backward order.
2
Substitution Coding
These questions involve 
replacing words with 
different words according 
to a given pattern. Careful 
tracking of the 
substitution chain is 
essential to arrive at the 
correct solution.
3
Mixed Letter Coding
This type presents 
phrases in coded language 
where you must identify 
the code for a specific 
word by finding common 
elements across multiple 
coded phrases.
Letter Coding: Solving Techniques
Backward Direction 
Values
Understanding the positional 
values of alphabets in reverse 
order (Z=1, Y=2, etc.) is crucial 
for many letter coding 
questions. Memorising these 
positions saves valuable time 
during exams.
Pattern Recognition
Analyze the pattern by 
comparing corresponding 
letters in the original word and 
its code. Look for consistent 
shifts in alphabet positions, 
such as +2/-2 alternating 
pattern shown in the PARKING 
³ RYTIKLI example.
Sample Solution
In the example where 
"PARKING" becomes 
"RYTIKLI" through alternating 
+2/-2 shifts, we can apply the 
same pattern to decode 
"FLOWERS" as "HJQUHPQ" by 
systematically applying the 
alternating shifts to each letter.
Substitution Coding
1
Original Word
Start with the word you need to decode. In the example, we need to find the national bird, 
which we know is the peacock.
2
Substitution Chain
Trace through the substitution sequence carefully. In the example, we see that 'Parrot' is 
known as 'Peacock' , 'Peacock' is known as 'Swallow' , and so on.
3
Final Decode
Identify the correct substitution. Since 'Peacock' is coded as 'Swallow' in the example, the 
national bird would be referred to as 'Swallow' in the coded language.