This document discusses substitution and transposition encryption techniques. Substitution techniques replace plaintext characters with other characters, numbers, or symbols, changing character identity but not position. Transposition techniques rearrange the character positions in the plaintext, changing character position but not identity. Examples of substitution techniques include the Caesar cipher, monoalphabetic ciphers, Playfair cipher, and Vigenère cipher. Transposition techniques examples are the rail fence cipher and row transposition cipher.

1. SUBSTITUTION AND TRANSPOSITION
TECHNIQUES
Name: Md Fazle Rabbi
ID:16CSE057

2. CONTENTS
 Cryptography
 Vocabulary
 Encryption & Decryption
 Substitution Technique
 Transmission Technique
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3. WHAT IS CRYPTOGRAPHY ?
 Cryptography is the science of using mathematics
to encrypt and decrypt data.
 Cryptography enables you to store sensitive
information or transmit it across insecure networks
so that it cannot be read by anyone except the
intended recipient.
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4. VOCABULARY
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o plaintext - the original message
o Cipher text - the coded message
o cipher - algorithm for transforming plaintext to ciphertext
o key - info used in cipher known only to sender/receiver
o encipher (encrypt) - converting plaintext to ciphertext
o decipher (decrypt) - recovering ciphertext from plaintext
o cryptography - study of encryption principles/methods
o cryptanalysis (codebreaking) - the study of principles/
methods of deciphering ciphertext without knowing key
o cryptology - the field of both cryptography and
cryptanalysis

5. CRYPTOGRAPHY BASIC
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6. TYPES OF CRYPTOGRAPHY
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7. CONTINUE…
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8. ASYMMETRIC CRYPTOGRAPHY
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9. Both Substitution cipher technique and Transposition cipher technique are
the types of Traditional cipher which are used to convert the plain text into
cipher text.
 Substitution Cipher Technique:
In Substitution Cipher Technique plain text characters are replaced with
other characters, numbers and symbols as well as in substitution Cipher
Technique, character’s identity is changed while its position remains
unchanged.
 Transposition Cipher Technique:
Transposition Cipher Technique rearranges the position of the plain text’s
characters. In transposition Cipher Technique, The position of the character
is changed but character’s identity is not changed.
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10. TYPES OF SUBSTITUTION CIPHER TECHNIQUE:
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Caesar Cipher
Monoalphabetic Ciphers
Playfair Cipher
Hill Cipher
Polyalphabetic Ciphers
Vigenère Cipher
Autokey Cipher
Vernam Ciphe

11. Transposition Techniques
o Rail Fence Cipher.
o Row Transposition Cipher.
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12. Row Transposition Cipher.
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13. THE END