Spyware
⚠️ Is a kind of malware that is designed to collect information and data on users and observe their activity without users' knowledge.
Other types of malware include functions or features designed for a specific purpose.
Ransomware
⚠️ for example, is designed to infect a user's system and encrypt the data.
⚠️ Cybercriminals then demand a ransom payment from the victim in exchange for decrypting the system's data.
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⚠️ Is a kind of malware that is designed to collect information and data on users and observe their activity without users' knowledge.
Other types of malware include functions or features designed for a specific purpose.
Ransomware
⚠️ for example, is designed to infect a user's system and encrypt the data.
⚠️ Cybercriminals then demand a ransom payment from the victim in exchange for decrypting the system's data.
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Computer Number System
1. Bit:
📌 Is the smallest unit of data representation.
📌 Is a space that can hold a single state.
2. Byte:
📌 Is the smallest unit of data measurement.
📌 Is a single group of 8 bits. [1 Byte = 8 Bits.]
3. Word:
📌 Is a group of 8 Bytes. [1 word = 8 Bytes.]
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1. Bit:
📌 Is the smallest unit of data representation.
📌 Is a space that can hold a single state.
2. Byte:
📌 Is the smallest unit of data measurement.
📌 Is a single group of 8 bits. [1 Byte = 8 Bits.]
3. Word:
📌 Is a group of 8 Bytes. [1 word = 8 Bytes.]
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Decimal Number System
Z = {0,1,2,3,4,5,6,7,8,9};
Base = 10
📌 Each position to the left of a digit increases by a power of 10.
📌 Each position to the right of a digit decreases by a power of 10.
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Z = {0,1,2,3,4,5,6,7,8,9};
Base = 10
📌 Each position to the left of a digit increases by a power of 10.
📌 Each position to the right of a digit decreases by a power of 10.
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Binary Number System
📌 Has two states 1(ON state)
and 0(OFF state).
Z = {0,1};
Base = 2
Unsigned number representation
With n bits we can represent 2^n unsigned integer numbers.
⚠️Remember: This ^ Indicates The Power Of
❗️ Range: from 0 to 2^n -1
So with 8 bits we can represent 2^8 = (256) numbers from 0 to 2^8 -1 = (255).
📌 Each position to the left of a digit increases by a power of 2.
📌 Each position to the right of a digit decreases by a power of 2.
Example:
(11001)2 = 1*2^0 + 0*2^1 + 0*2^2 + 1*2^3 + 1*2^4
= (25)10
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📌 Has two states 1(ON state)
and 0(OFF state).
Z = {0,1};
Base = 2
Unsigned number representation
With n bits we can represent 2^n unsigned integer numbers.
⚠️Remember: This ^ Indicates The Power Of
❗️ Range: from 0 to 2^n -1
So with 8 bits we can represent 2^8 = (256) numbers from 0 to 2^8 -1 = (255).
📌 Each position to the left of a digit increases by a power of 2.
📌 Each position to the right of a digit decreases by a power of 2.
Example:
(11001)2 = 1*2^0 + 0*2^1 + 0*2^2 + 1*2^3 + 1*2^4
= (25)10
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Signed number representation
▶️ Here we would need to consider sign, meaning we represent both positive and negative numbers.
📌 Sign and magnitude
With this method we reserve the most significant bit of the left most bit for sign.
This bit is called sign bit.
range becomes from -2^n-1 -1 to 2^n-1 -1
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▶️ Here we would need to consider sign, meaning we represent both positive and negative numbers.
📌 Sign and magnitude
With this method we reserve the most significant bit of the left most bit for sign.
This bit is called sign bit.
range becomes from -2^n-1 -1 to 2^n-1 -1
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Octal Number System
Z = {0,1,2,3,4,5,6,7};
Base = 8
📌 Each position to the left of a digit increases by a power of 8.
📌 Each position to the right of a digit decreases by a power of 8.
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Z = {0,1,2,3,4,5,6,7};
Base = 8
📌 Each position to the left of a digit increases by a power of 8.
📌 Each position to the right of a digit decreases by a power of 8.
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Hexadecimal Number System
Z = (0,1,2,3,4,5,6,7,8,9, A, B, C, D, E, F};
Base = 16
📌 Each position to the left of a digit increases by a power of 16.
📌 Each position to the right of a digit decreases by a power of 16.
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Z = (0,1,2,3,4,5,6,7,8,9, A, B, C, D, E, F};
Base = 16
📌 Each position to the left of a digit increases by a power of 16.
📌 Each position to the right of a digit decreases by a power of 16.
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