Network System and Security Part-1

 

1. Plaintext (اصل Data / Original Message)

Plaintext wo normal readable data hota hai jo kisi ne likha ho ya bhejna ho, bina kisi protection k.

Example:
Agar aap WhatsApp pe likho:
"Hello Manan, Meet me at 5pm" – ye plaintext hai.
Ye kisi bhi banda easily parh sakta hai.

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2. Ciphertext (خفیہ Data / Hidden Message)

Ciphertext wo data hota hai jo encrypt (lock) kia gaya hota hai taake koi doosra usay na parh sakay.

Example:
Agar "Hello Manan" ko encrypt karo to ban sakta hai:
"Xlwwr Qfrfr"
Ab ye ciphertext hai. Sirf jis k paas key hogi wo isay wapas original me badal sakta hai.

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3. Encryption (Lock Karna / Data ko Secure Karna)

Encryption ka matlab hota hai plaintext ko ciphertext me badalna – yani data ko lock kar dena.

Example:
Aapka message: "Meet me at 5pm"
Encryption k baad: "Pfhy ph cv 5ro"
Ab ye safe hai, koi beech me data churaye to bhi samajh nahi sakta.

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4. Decryption (Unlock Karna / Data ko Wapas Readable Banana)

Decryption ka matlab hota hai ciphertext ko wapas plaintext me laana – yani data unlock karna.

Example:
Ciphertext: "Pfhy ph cv 5ro"
Decryption k baad: "Meet me at 5pm"

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5. Cryptography (Data ko Secret bananay ka Science)

Cryptography wo technique ya science hoti hai jis se hum encryption aur decryption karte hain.

Example:
Jese WhatsApp apna system use karta hai messages ko secure karne k liye – ye cryptography hai.
Ye ensure karta hai k sirf sender aur receiver hi message parh sakay.

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6. Cryptoanalyst (Jo lock toray / Hacker-type ya Security Expert)

Cryptoanalyst wo banda hota hai jo encryption torne ki koshish karta hai – ya to good purpose (security test) ya illegal purpose.

Example:
Agar koi hacker aapka encrypted message tor k samajhne ki koshish kare, to wo cryptoanalyst kehlay ga.

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🔐 Ek Simple Real-Life Example:

• Plaintext: "ATM PIN is 1234"

• Encryption (Lock): "XTD YKL QN 5678"

• Ciphertext: "XTD YKL QN 5678"

• Decryption (Unlock): "ATM PIN is 1234"

• Cryptography: Yeh pura process jise encryption/decryption hota hai.

• Cryptoanalyst: Jo is ciphertext ko bina key ke unlock karne ki koshish kare.