/* [<][>][^][v][top][bottom][index][help] */
DEFINITIONS
This source file includes following definitions.
- FinalizeSignature
- GetSignatureInfo
- SignatureImage
- TransformSignature
- UpdateSignature
/*
% Copyright (C) 2003 GraphicsMagick Group
% Copyright (C) 2002 ImageMagick Studio
% Copyright 1991-1999 E. I. du Pont de Nemours and Company
%
% This program is covered by multiple licenses, which are described in
% Copyright.txt. You should have received a copy of Copyright.txt with this
% package; otherwise see http://www.graphicsmagick.org/www/Copyright.html.
%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% %
% %
% SSSSS IIIII GGGG N N AAA TTTTT U U RRRR EEEEE %
% SS I G NN N A A T U U R R E %
% SSS I G GG N N N AAAAA T U U RRRR EEE %
% SS I G G N NN A A T U U R R E %
% SSSSS IIIII GGG N N A A T UUU R R EEEEE %
% %
% %
% Methods to Compute a Message Digest for an Image %
% %
% %
% Software Design %
% John Cristy %
% December 1992 %
% %
% %
% %
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
%
%
*/
/*
Include declarations.
*/
#include "magick/studio.h"
#include "magick/attribute.h"
#include "magick/monitor.h"
#include "magick/pixel_cache.h"
#include "magick/signature.h"
#include "magick/utility.h"
/*
Define declarations.
*/
#define Trunc32(x) ((x) & 0xffffffffUL)
/*
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% %
% %
% %
% F i n a l i z e S i g n a t u r e %
% %
% %
% %
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
% Method FinalizeSignature finalizes the SHA message digest computation.
%
% The format of the FinalizeSignature method is:
%
% FinalizeSignature(SignatureInfo *signature_info)
%
% A description of each parameter follows:
%
% o signature_info: The address of a structure of type SignatureInfo.
%
%
*/
MagickExport void FinalizeSignature(SignatureInfo *signature_info)
{
long
count;
unsigned long
high_order,
low_order;
/*
Finalize computing the SHA digest.
*/
low_order=signature_info->low_order;
high_order=signature_info->high_order;
count=(long) ((low_order >> 3) & 0x3f);
signature_info->message[count++]=0x80;
if (count <= (SignatureSize-8))
(void) memset(signature_info->message+count,0,SignatureSize-8-count);
else
{
(void) memset(signature_info->message+count,0,SignatureSize-count);
TransformSignature(signature_info);
(void) memset(signature_info->message,0,SignatureSize-8);
}
signature_info->message[56]=(unsigned char) (high_order >> 24);
signature_info->message[57]=(unsigned char) (high_order >> 16);
signature_info->message[58]=(unsigned char) (high_order >> 8);
signature_info->message[59]=(unsigned char) high_order;
signature_info->message[60]=(unsigned char) (low_order >> 24);
signature_info->message[61]=(unsigned char) (low_order >> 16);
signature_info->message[62]=(unsigned char) (low_order >> 8);
signature_info->message[63]=(unsigned char) low_order;
TransformSignature(signature_info);
}
/*
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% %
% %
% %
% G e t S i g n a t u r e I n f o %
% %
% %
% %
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
% Method GetSignatureInfo initializes the SHA message digest structure.
%
% The format of the GetSignatureInfo method is:
%
% GetSignatureInfo(SignatureInfo *signature_info)
%
% A description of each parameter follows:
%
% o signature_info: The address of a structure of type SignatureInfo.
%
%
*/
MagickExport void GetSignatureInfo(SignatureInfo *signature_info)
{
(void) memset(signature_info,0,sizeof(SignatureInfo));
signature_info->digest[0]=0x6a09e667UL;
signature_info->digest[1]=0xbb67ae85UL;
signature_info->digest[2]=0x3c6ef372UL;
signature_info->digest[3]=0xa54ff53aUL;
signature_info->digest[4]=0x510e527fUL;
signature_info->digest[5]=0x9b05688cUL;
signature_info->digest[6]=0x1f83d9abUL;
signature_info->digest[7]=0x5be0cd19UL;
}
/*
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% %
% %
% %
% S i g n a t u r e I m a g e %
% %
% %
% %
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
% SignatureImage() computes a message digest from an image pixel stream with
% an implementation of the NIST SHA-256 Message Digest algorithm. This
% signature uniquely identifies the image and is convenient for determining
% if an image has been modified or whether two images are identical.
%
% The format of the SignatureImage method is:
%
% unsigned int SignatureImage(Image *image)
%
% A description of each parameter follows:
%
% o image: The image.
%
%
*/
#define SignatureImageText "[%s] Compute SHA-256 signature..."
MagickExport unsigned int SignatureImage(Image *image)
{
char
signature[MaxTextExtent];
const IndexPacket
*indexes;
long
y;
register const PixelPacket
*p;
register long
x;
register unsigned char
*q;
SignatureInfo
signature_info;
unsigned char
*message;
unsigned long
quantum;
/*
Allocate memory for digital signature.
*/
assert(image != (Image *) NULL);
assert(image->signature == MagickSignature);
message=MagickAllocateMemory(unsigned char *,20*image->columns);
if (message == (unsigned char *) NULL)
ThrowBinaryException3(ResourceLimitError,MemoryAllocationFailed,
UnableToComputeImageSignature);
/*
Compute image digital signature.
*/
GetSignatureInfo(&signature_info);
for (y=0; y < (long) image->rows; y++)
{
p=AcquireImagePixels(image,0,y,image->columns,1,&image->exception);
if (p == (const PixelPacket *) NULL)
break;
indexes=AccessImmutableIndexes(image);
q=message;
for (x=0; x < (long) image->columns; x++)
{
quantum=ScaleQuantumToLong(p->red);
*q++=(unsigned char) (quantum >> 24);
*q++=(unsigned char) (quantum >> 16);
*q++=(unsigned char) (quantum >> 8);
*q++=(unsigned char) quantum;
quantum=ScaleQuantumToLong(p->green);
*q++=(unsigned char) (quantum >> 24);
*q++=(unsigned char) (quantum >> 16);
*q++=(unsigned char) (quantum >> 8);
*q++=(unsigned char) quantum;
quantum=ScaleQuantumToLong(p->blue);
*q++=(unsigned char) (quantum >> 24);
*q++=(unsigned char) (quantum >> 16);
*q++=(unsigned char) (quantum >> 8);
*q++=(unsigned char) quantum;
if (!image->matte)
{
if (image->colorspace == CMYKColorspace)
{
quantum=ScaleQuantumToLong(p->opacity);
*q++=(unsigned char) (quantum >> 24);
*q++=(unsigned char) (quantum >> 16);
*q++=(unsigned char) (quantum >> 8);
*q++=(unsigned char) quantum;
}
quantum=ScaleQuantumToLong(OpaqueOpacity);
*q++=(unsigned char) (quantum >> 24);
*q++=(unsigned char) (quantum >> 16);
*q++=(unsigned char) (quantum >> 8);
*q++=(unsigned char) quantum;
}
else
{
quantum=ScaleQuantumToLong(p->opacity);
*q++=(unsigned char) (quantum >> 24);
*q++=(unsigned char) (quantum >> 16);
*q++=(unsigned char) (quantum >> 8);
*q++=(unsigned char) quantum;
if (image->colorspace == CMYKColorspace)
{
quantum=ScaleQuantumToLong(indexes[x]);
*q++=(unsigned char) (quantum >> 24);
*q++=(unsigned char) (quantum >> 16);
*q++=(unsigned char) (quantum >> 8);
*q++=(unsigned char) quantum;
}
}
p++;
}
UpdateSignature(&signature_info,message,q-message);
if (QuantumTick(y,image->rows))
if (!MagickMonitorFormatted(y,image->rows,&image->exception,
SignatureImageText,image->filename))
break;
}
FinalizeSignature(&signature_info);
MagickFreeMemory(message);
/*
Convert digital signature to a 64 character hex string.
*/
FormatString(signature,"%08lx%08lx%08lx%08lx%08lx%08lx%08lx%08lx",
signature_info.digest[0],signature_info.digest[1],signature_info.digest[2],
signature_info.digest[3],signature_info.digest[4],signature_info.digest[5],
signature_info.digest[6],signature_info.digest[7]);
(void) SetImageAttribute(image,"signature",(char *) NULL);
(void) SetImageAttribute(image,"signature",signature);
return(True);
}
/*
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% %
% %
% %
% T r a n s f o r m S i g n a t u r e %
% %
% %
% %
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
% TransformSignature() transforms the SHA message digest.
%
% The format of the TransformSignature method is:
%
% TransformSignature(SignatureInfo *signature_info)
%
% A description of each parameter follows:
%
% o signature_info: The address of a structure of type SignatureInfo.
%
%
*/
MagickExport void TransformSignature(SignatureInfo *signature_info)
{
#define Ch(x,y,z) (((x) & (y))^(~(x) & (z)))
#define Maj(x,y,z) (((x) & (y))^((x) & (z))^((y) & (z)))
#define Rot32(x,n) Trunc32(((x >> n) | (x << (32-n))))
#define Sigma0(x) (Rot32(x,7)^Rot32(x,18)^Trunc32(x >> 3))
#define Sigma1(x) (Rot32(x,17)^Rot32(x,19)^Trunc32(x >> 10))
#define Suma0(x) (Rot32(x,2)^Rot32(x,13)^Rot32(x,22))
#define Suma1(x) (Rot32(x,6)^Rot32(x,11)^Rot32(x,25))
static unsigned long
K[64] =
{
0x428a2f98UL, 0x71374491UL, 0xb5c0fbcfUL, 0xe9b5dba5UL, 0x3956c25bUL,
0x59f111f1UL, 0x923f82a4UL, 0xab1c5ed5UL, 0xd807aa98UL, 0x12835b01UL,
0x243185beUL, 0x550c7dc3UL, 0x72be5d74UL, 0x80deb1feUL, 0x9bdc06a7UL,
0xc19bf174UL, 0xe49b69c1UL, 0xefbe4786UL, 0x0fc19dc6UL, 0x240ca1ccUL,
0x2de92c6fUL, 0x4a7484aaUL, 0x5cb0a9dcUL, 0x76f988daUL, 0x983e5152UL,
0xa831c66dUL, 0xb00327c8UL, 0xbf597fc7UL, 0xc6e00bf3UL, 0xd5a79147UL,
0x06ca6351UL, 0x14292967UL, 0x27b70a85UL, 0x2e1b2138UL, 0x4d2c6dfcUL,
0x53380d13UL, 0x650a7354UL, 0x766a0abbUL, 0x81c2c92eUL, 0x92722c85UL,
0xa2bfe8a1UL, 0xa81a664bUL, 0xc24b8b70UL, 0xc76c51a3UL, 0xd192e819UL,
0xd6990624UL, 0xf40e3585UL, 0x106aa070UL, 0x19a4c116UL, 0x1e376c08UL,
0x2748774cUL, 0x34b0bcb5UL, 0x391c0cb3UL, 0x4ed8aa4aUL, 0x5b9cca4fUL,
0x682e6ff3UL, 0x748f82eeUL, 0x78a5636fUL, 0x84c87814UL, 0x8cc70208UL,
0x90befffaUL, 0xa4506cebUL, 0xbef9a3f7UL, 0xc67178f2UL
}; /* 32-bit fractional part of the cube root of the first 64 primes */
int
j,
shift;
register long
i;
register unsigned char
*p;
unsigned long
A,
B,
C,
D,
E,
F,
G,
H,
lsb_first,
T,
T1,
T2,
W[64];
shift=32;
p=signature_info->message;
lsb_first=1;
if (*(char *) &lsb_first)
{
if (sizeof(lsb_first) > 4)
for (i=0; i < 16; i+=2)
{
T=(*((unsigned long *) p));
p+=8;
W[i]=((T << 24) & 0xff000000U) | ((T << 8) & 0x00ff0000U) |
((T >> 8) & 0x0000ff00U) | ((T >> 24) & 0x000000ffU);
T>>=shift;
W[i+1]=((T << 24) & 0xff000000U) | ((T << 8) & 0x00ff0000U) |
((T >> 8) & 0x0000ff00U) | ((T >> 24) & 0x000000ffU);
}
else
for (i=0; i < 16; i++)
{
T=(*((unsigned long *) p));
p+=4;
W[i]=((T << 24) & 0xff000000U) | ((T << 8) & 0x00ff0000U) |
((T >> 8) & 0x0000ff00U) | ((T >> 24) & 0x000000ffU);
}
}
else
{
if (sizeof(lsb_first) > 4)
for (i=0; i < 16; i+=2)
{
T=(*((unsigned long *) p));
p+=8;
W[i]=Trunc32(T >> shift);
W[i+1]=Trunc32(T);
}
else
for (i=0; i < 16; i++)
{
T=(*((unsigned long *) p));
p+=4;
W[i]=Trunc32(T);
}
}
A=signature_info->digest[0];
B=signature_info->digest[1];
C=signature_info->digest[2];
D=signature_info->digest[3];
E=signature_info->digest[4];
F=signature_info->digest[5];
G=signature_info->digest[6];
H=signature_info->digest[7];
for (i=16; i < 64; i++)
W[i]=Trunc32(Sigma1(W[i-2])+W[i-7]+Sigma0(W[i-15])+W[i-16]);
for (j=0; j < 64; j++)
{
T1=Trunc32(H+Suma1(E)+Ch(E,F,G)+K[j]+W[j]);
T2=Trunc32(Suma0(A)+Maj(A,B,C));
H=G;
G=F;
F=E;
E=Trunc32(D+T1);
D=C;
C=B;
B=A;
A=Trunc32(T1+T2);
}
signature_info->digest[0]=Trunc32(signature_info->digest[0]+A);
signature_info->digest[1]=Trunc32(signature_info->digest[1]+B);
signature_info->digest[2]=Trunc32(signature_info->digest[2]+C);
signature_info->digest[3]=Trunc32(signature_info->digest[3]+D);
signature_info->digest[4]=Trunc32(signature_info->digest[4]+E);
signature_info->digest[5]=Trunc32(signature_info->digest[5]+F);
signature_info->digest[6]=Trunc32(signature_info->digest[6]+G);
signature_info->digest[7]=Trunc32(signature_info->digest[7]+H);
}
/*
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% %
% %
% %
% U p d a t e S i g n a t u r e %
% %
% %
% %
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
% UpdateSignature() updates the SHA message digest.
%
% The format of the UpdateSignature method is:
%
% UpdateSignature(SignatureInfo *signature_info,
% const unsigned char *message,const size_t length)
%
% A description of each parameter follows:
%
% o signature_info: The address of a structure of type SignatureInfo.
%
% o message: the message
%
% o length: The length of the message.
%
%
*/
MagickExport void UpdateSignature(SignatureInfo *signature_info,
const unsigned char *message,const size_t length)
{
register long
i;
size_t
n;
unsigned long
count;
/*
Update the SHA digest.
*/
n=length;
count=Trunc32(signature_info->low_order+((unsigned char) n << 3));
if (n < signature_info->low_order)
signature_info->high_order++;
signature_info->low_order=count;
signature_info->high_order+=(unsigned char) (n >> 29);
if (signature_info->offset)
{
i=SignatureSize-signature_info->offset;
if (i > (long) n)
i=(long) n;
(void) memcpy(signature_info->message+signature_info->offset,message,i);
n-=i;
message+=i;
signature_info->offset+=i;
if (signature_info->offset != SignatureSize)
return;
TransformSignature(signature_info);
}
while (n >= SignatureSize)
{
(void) memcpy(signature_info->message,message,SignatureSize);
message+=SignatureSize;
n-=SignatureSize;
TransformSignature(signature_info);
}
(void) memcpy(signature_info->message,message,n);
signature_info->offset=(long) n;
}