Cryptogrtaphy Project

Cryptography

Substitution Cipher

Encrypting and decrypting answers

#1 Substitution Cipher

#1a Encrypt the answer using the key above part (by substitution), so that 2nd row is encrypted

Ex: Take the D (plaintext) look on the key and substitute I from the Encryption into the row Encrypted row

#1b Decrypt the plaintext by decrypting the encrypted code backward for plain text

Part a requires you to encrypt the plaintext

Part b requires you to covert the encrypted text to plaintext

Initial yield:

A

B

C

D

E

F

G

H

I

J

K

L

M

N

O

P

Q

R

S

T

U

V

W

X

Y

Z

Encryption:

F

G

H

I

J

K

L

M

N

O

P

Q

R

S

T

U

V

W

X

Y

Z

A

B

C

D

E

Ex: Take the U from the encrypted row and work backward by looking at the Encryption key find U and substitute P from Initial Yield key into the Plaintext row

a) Encrypt the answer

Plaintext:

D

O

Y

O

U

K

N

O

W

A

L

L

A

B

O

U

T

T

H

E

C

Y

T

O

G

R

A

P

H

Y

Encrypted:

b) Unencrypt the answer

Plaintext:

Encrypted:

U

W

N

S

H

N

U

Q

J

X

T

K

N

S

K

T

W

R

F

Y

N

T

S

X

J

H

Z

W

N

Y

D

2) Transposition Cipher

Part a requires you to encrypt the plaintext

Part b requires you to covert the encrypted text to plaintext

Key Pattern: 1 to 4, 2 to 8, 3 to 1, 4 to 5, 5 to 7, 6 to 2, 7 to 6, 8 to 3

#2 Transposition Cipher

#2a Use the Key pattern and move letter from location to new location (Transposition)

Ex: location 8 has a I, Key pattern says to move location 8 to 3, so put the I in location 3 on Cypertext row

#2b Reverse use the key pattern

Ex: location 8 has a N in Cypertext row, Where did it come from to get to 8, the key pattern says 2 to 8, so backward would move N to location 2

a) What is the Cypertext

Location:	8	7	6	5	4	3	2	1	8	7	6	5	4	3	2	1	8	7	6	5	4	3	2	1	8	7	6	5	4	3	2	1
Plaintext:	I	A	M	H	A	V	I	N	G	A	L	O	T	O	F	F	U	N	H	O	W	A	R	E	Y	O	U	D	O	I	N	G
Cypertext:

b) Convert back to Plaintext

Location:	8	7	6	5	4	3	2	1	8	7	6	5	4	3	2	1	8	7	6	5	4	3	2	1	8	7	6	5	4	3	2	1
Plaintext:
Cypertext:	N	O	O	U	O	D	Y	K	S	E	T	A	W	W	H	N	I	O	R	T	S	E	T	H	O	S	U	T	N	Q	E	I

3. Exclusive OR

Part a requires you to encrypt the plaintext

Part b requires you to covert the encrypted text to plaintext

a) Plaintext SECURITY

Create the binary of each ASCII letter

Apply the Cypher Key 6 (00110110) to encrypt using Exclusive OR the plain text

#3 Exclusive OR

3a Insert the ASCII hex code for S in plain binary row; insert the Cypher key V code in Cypher Key row, then do an exclusive OR ( 0 & 0 = 0, 1 & 0 = 1, 0 & 1 = 1, 1 & 1 = 0) and put it in the Cipher Answer

3b same as 3a but reverse by looking at the cipher result (found from the Encrypted 7(342 and put in the Cipher answer row. Then using backward the cypher key to know what the plaintext should be; then retrieve binary value from the ASCII table to the letter in Answer Plaintext row.

Location:	8	7	6	5	4	3			2	1	8	7	6	5	4	3	2	1	8	7	6	5	4	3	2	1	8	7	6	5	4	3	2	1	8	7	6	5	4	3	2	1
Plaintext			S								E								C								U								R
Plainbinary:
Cypher Key
Cipher Answer:

Location:	8	7	6	5	4	3	2	1	8	7	6	5	4	3	2	1	8	7	6	5	4	3	2	1
Plaintext	I								T								Y
Plainbinary:
Cypher Key
Cipher Answer:

b) Encrypted: 7(342

Find the plaintext

Unencrypt this was encrypted applied with a (01100001):

Location:	8	7	6	5	4	3	2	1	8	7	6	5	4	3	2	1	8	7	6	5	4	3	2	1	8	7	6	5	4	3	2	1	8	7	6	5	4	3	2	1
Answer Plaintext
Plain binary:
Cypher Key
Cipher binary:
Cipher text:	7								(								3								4								2

4) Vernam Cipher

Part a requires you to encrypt the plaintext

Part b requires you to covert the encrypted cyphertext to plaintext

A=1, B=2, , Z=26

#4 Vernam Cipher

4a

Substitute the value 1-26 corresponding to the letters (Ex A=1)

Substitute the value of the On-Time Pad Text to the One-Time Pad Value

Sum up the two values in the Sum of plaintext pad

If the value in the Sum of plaintext pad > 26 then subtract 26 and put result in After modulo subtract row

Then put the letter from the value from the Sum of plaintext pad, but use the After modulo subtract row for the value. (If value is 3 then put C in Cyptertext row)

4b Works backward (challenge) the plaintext may not look correct so then you have to think what letter it should be then insert the After modulo subtract value to get the correct letter.

a)

Plaintext:

I

N

F

O

R

M

A

T

I

O

N

I

S

I

M

P

O

R

T

A

N

T

Plain Text value

One-Time Pad Text

P

G

R

I

F

K

X

L

Q

A

J

M

C

H

B

D

E

O

S

V

P

N

One-Time Pad Value:

Sum of plaintext pad:

After modulo subtract:

Cypertext:

b)

Plaintext:

Plain Text value

One-Time Pad Text

X

F

J

W

D

A

E

T

O

U

C

G

B

L

I

H

One-Time Pad Value:

Sum of plaintext pad:

After modulo subtract:

Cypertext:

Y

X

O

V

S

V

X

U

U

Z

R

U

N

U

W

M

5) Create your own cipher methods.

Be creative

Do not use existing method

Could be some combination

#5 Be imaginative DO NOT use existing online; can be combination of modes show or found. But try to make something new