TEXT -> IMAGE ENCODING FLOWCHART (LSB METHOD) start. store color depth of screen. false. false initialize psuedo rand # generator.

Transcription

1 TXT -> IMG NOING FLOWHRT (LS MTHO) initialize pre-defined alphabet number codes store color depth of screen load image for encoding color depth < 24? switch color depth to >= 24 bit ask use for ization type end key? initialize psuedo rand # generator ask for key flag=0 initialize V # (rnd) generator dataentry flag=1 placetextpixels LS

2 store max height and width of pic initialize 2-d flag array choose loc to store length of message flag= 1? loc (x,y) as get color of pixel at pt(x, y) and convert to hex split into r,g,b in hex then binary convert length of message into binary

3 form new 24bit binary by taking left 6 bits of original blue and attach it to left most 2bits of binary rep of length of message. Then attach this to the left 5 bits of the green and the next 3bits of the binary rep of the length of message. Finally attach this to the left 5 bits of red and the 3 right most bits of the binary rep of the length of the message convert new formed binary to dec plot new color for the length pixel G generate loc(x,y) between 0-xmax and 0-ymax flag = 1? F F location as get color of pixel at loc (x,y) and convert to hex split into r,g,b values in hex and then into binary convert alphabet numeric code of char in message to binary

4 form a new 24bit binary number by taking the left 6bits of the original blue and attach it to the left most two bits of the binary rep of the character coded number. Then attach this to the left 5 bits of the green and the next three bits of the binary rep of the char coded number. Finally attach this to the left 5 bits of the red and the 3 right most bits of the binary rep of the char coded number convert new formed binary to dec plot new color for character last character? G round length of message up to nearest multiple of 5 pad message with blanks to make sure message length is multiple of 5 ask user for message to encode row=length/5 column=5 Tablencode convert each char of table encoded message to its corresponding alphabet number code fill 2d table with each char in a row wise fashion encode message by forming new message by going down each column

5 TXT -> IMG OING FLOWHRT (LS MTHO) initialize pre-defined alphabet number codes store color depth of screen load image for decoding color depth < 24? switch color depth to >= 24 bit ask use for ization type end key? initialize psuedo rand # generator ask for key flag=0 store max height and width ofpic initialize V # (rnd) generator flag=1

6 initialize 2d flag array get color at loc that indicates length of message and convert to hex flag =1? location as split into r,g,b in hex then convert to binary form a new 8 bit binary number by taking the two right most bits of blue, the 3 right most bits of green and the 3 right most bits of blue convert new binary value to decimal - this represents length of message generate loc(x,y) between 0-xmax and 0-ymax flag = 1? location as

7 get color of pixel at loc(x,y) and convert to hex split into r,g,b in hex and then convert to binary form a new 8bit binary number by taking the two right most bits of blue, the three right most bits of green and the 3 right most bits of blue convert new binary value to decimal and determine the alphabetic value for it attach character to string accumulator to form secret message last character? tabledecode display decoded message row=5 column=length of secret message/5 fill in 2d table with each character of the secret message in a row wise fashion form the new decoded secret message by going down each column and attaching each character