For the particular question in Assembly Language for x86 Processor (6th Edition) chapter 6.9 problem 11PE, the line of code xor buffer[esi], key[edc] I keep getting an error saying invalid instruction operands. My work is the same as the textbook and I do not know what i did wrong. The particular line I am having trouble with is in the Convert Text Method in the Label1 loop.

TITLE Message Encryption (msgEncrypt.asm) This program clears the screen, inputs the key and plain text from user, encrypt plain text and display it, decrypt;the cipher text and display it INCLUDE Irvine32.inc BUFMAX = 128 KEYMAX = BUFMAX .data strKey BYTE "Enter the key: ", 0 strText BYTE "Enter the plain text:", 0 strEnc BYTE "The encrypted text is: ",0 strDec BYTE "The decrypted text is: "0 buffer BYTE BUFMAX+1 DUP (O) bufSize DWORD? key BYTE KEYMAX+1 DUP (0) keySize DWORD .code main PROC calls the procedures call CIrscr ; clears the screen