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17011628_박찬흠 #118

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17011628_박찬흠 #118

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976832c
Create README.md
Edell1 Dec 6, 2018
c2fb96d
Update SteganographyHelper.cs
Edell1 Dec 6, 2018
5b2a128
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Edell1 Dec 6, 2018
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48 changes: 27 additions & 21 deletions Steganography/SteganographyHelper.cs
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Original file line number Diff line number Diff line change
@@ -1,4 +1,4 @@
using System;
using System;
using System.Drawing;

namespace Steganography
Expand All @@ -11,7 +11,7 @@ public enum State
Filling_With_Zeros
};

public static Bitmap embedText(string text, Bitmap bmp)
public static Bitmap embedText(string text, Bitmap bmp)//이미지 파일에 text 숨기기
{
State state = State.Hiding;

Expand All @@ -29,33 +29,33 @@ public static Bitmap embedText(string text, Bitmap bmp)
{
for (int j = 0; j < bmp.Width; j++)
{
Color pixel = bmp.GetPixel(j, i);
Color pixel = bmp.GetPixel(j, i);//파일의 픽셀

R = pixel.R - pixel.R % 2;
G = pixel.G - pixel.G % 2;
B = pixel.B - pixel.B % 2;

//픽셀별로 R,G,B 변수들을 RGB값이 각각 짝수일땐 0, 홀수일땐 1로 저장
for (int n = 0; n < 3; n++)
{
if (pixelElementIndex % 8 == 0)
{
if (state == State.Filling_With_Zeros && zeros == 8)
{
if ((pixelElementIndex - 1) % 3 < 2)
if ((pixelElementIndex - 1) % 3 < 2)//pixelElementIndex값이 3배수가 아닐때
{
bmp.SetPixel(j, i, Color.FromArgb(R, G, B));
bmp.SetPixel(j, i, Color.FromArgb(R, G, B));//픽셀의 RGB값을 저장
}

return bmp;
}

if (charIndex >= text.Length)
if (charIndex >= text.Length)//text의 길이보다 charIndex값이 더 길때, 즉 모든 text를 숨겼을때
{
state = State.Filling_With_Zeros;
}
else
{
charValue = text[charIndex++];
charValue = text[charIndex++];//숨길 text의 각각의 값을 저장
}
}

Expand All @@ -68,7 +68,8 @@ public static Bitmap embedText(string text, Bitmap bmp)
R += charValue % 2;
charValue /= 2;
}
} break;
}
break;
case 1:
{
if (state == State.Hiding)
Expand All @@ -77,7 +78,8 @@ public static Bitmap embedText(string text, Bitmap bmp)

charValue /= 2;
}
} break;
}
break;
case 2:
{
if (state == State.Hiding)
Expand All @@ -88,7 +90,8 @@ public static Bitmap embedText(string text, Bitmap bmp)
}

bmp.SetPixel(j, i, Color.FromArgb(R, G, B));
} break;
}
break;
}

pixelElementIndex++;
Expand All @@ -104,7 +107,7 @@ public static Bitmap embedText(string text, Bitmap bmp)
return bmp;
}

public static string extractText(Bitmap bmp)
public static string extractText(Bitmap bmp)//숨긴 text를 추출
{
int colorUnitIndex = 0;
int charValue = 0;
Expand All @@ -123,36 +126,39 @@ public static string extractText(Bitmap bmp)
case 0:
{
charValue = charValue * 2 + pixel.R % 2;
} break;
}
break;
case 1:
{
charValue = charValue * 2 + pixel.G % 2;
} break;
}
break;
case 2:
{
charValue = charValue * 2 + pixel.B % 2;
} break;
}
break;
}

colorUnitIndex++;

if (colorUnitIndex % 8 == 0)
{
charValue = reverseBits(charValue);
charValue = reverseBits(charValue);//뒤에서부터 추출하므로 추출한 값을 reverse

if (charValue == 0)
if (charValue == 0)//모든 text를 추출완료했을때
{
return extractedText;
return extractedText;//text를 출력하고 종료
}
char c = (char)charValue;
char c = (char)charValue;//charValuer값을 char로 변환

extractedText += c.ToString();
extractedText += c.ToString();//변환된 값을 extractedText에 저장
}
}
}
}

return extractedText;
return extractedText;//text를 출력하고 종료
}

public static int reverseBits(int n)
Expand Down