Write a procedure for encryption by rotating each plaintext byte different number of positions. For example, in the following array that represents the encryption key, each number indicates a left rotation: key BYTE 6, 4, 1, 2, 7, 5, 2, 4, 3, 6. Pass the pointer to the text string in EDX, the array size to ECX, a pointer to the key array in ESI, and the direction value (0 or 1) in EBX. Assume that the key array size is 10. Your procedure should loop through plain text and align the key to the first 10 bytes of the message. Rotate each plain text to the left (if the value in EBX is 0) or to the right (if the value in EBX is 1) by the amount in the key array: first byte by 6, second byte by 4 etc. Then align the key to the next 10 bytes until the whole message is encrypted. Write a program that tests the procedure by calling : one time with EBX = 0 (encrypting), then with EBX = 1 (decrypting). Print out the text three times: the original, then the encrypted, then t

Database System Concepts
7th Edition
ISBN:9780078022159
Author:Abraham Silberschatz Professor, Henry F. Korth, S. Sudarshan
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Chapter1: Introduction
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Write a procedure for encryption by rotating each plaintext byte different number of positions. For example, in the following array that represents the encryption key, each number indicates a left rotation:

key BYTE 6, 4, 1, 2, 7, 5, 2, 4, 3, 6.

Pass the pointer to the text string in EDX, the array size to ECX, a pointer to the key array in ESI, and the direction value (0 or 1) in EBX. Assume that the key array size is 10.

Your procedure should loop through plain text and align the key to the first 10 bytes of the message. Rotate each plain text to the left (if the value in EBX is 0) or to the right (if the value in EBX is 1) by the amount in the key array: first byte by 6, second byte by 4 etc. Then align the key to the next 10 bytes until the whole message is encrypted.

Write a program that tests the procedure by calling : one time with EBX = 0 (encrypting), then with EBX = 1 (decrypting).

Print out the text three times: the original, then the encrypted, then the decrypted.

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