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//========================================================================
//
// Decrypt.cc
//
// Copyright 1996-2003 Glyph & Cog, LLC
//
//========================================================================

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//========================================================================
//
// Modified under the Poppler project - http://poppler.freedesktop.org
//
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// All changes made under the Poppler project to this file are licensed
// under GPL version 2 or later
//
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// Copyright (C) 2008 Julien Rebetez <julien@fhtagn.net>
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// Copyright (C) 2008, 2010 Albert Astals Cid <aacid@kde.org>
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// Copyright (C) 2009 Matthias Franz <matthias@ktug.or.kr>
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// Copyright (C) 2009 David Benjamin <davidben@mit.edu>
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//
// To see a description of the changes please see the Changelog file that
// came with your tarball or type make ChangeLog if you are building from git
//
//========================================================================

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#include <config.h>

#ifdef USE_GCC_PRAGMAS
#pragma implementation
#endif

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#include <string.h>
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#include "goo/gmem.h"
#include "Decrypt.h"
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#include "Error.h"
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static void aesKeyExpansion(DecryptAESState *s,
			    Guchar *objKey, int objKeyLen);
static void aesDecryptBlock(DecryptAESState *s, Guchar *in, GBool last);
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static void aes256KeyExpansion(DecryptAES256State *s,
			       Guchar *objKey, int objKeyLen);
static void aes256DecryptBlock(DecryptAES256State *s, Guchar *in, GBool last);
static void sha256(Guchar *msg, int msgLen, Guchar *hash);
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static const Guchar passwordPad[32] = {
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  0x28, 0xbf, 0x4e, 0x5e, 0x4e, 0x75, 0x8a, 0x41,
  0x64, 0x00, 0x4e, 0x56, 0xff, 0xfa, 0x01, 0x08, 
  0x2e, 0x2e, 0x00, 0xb6, 0xd0, 0x68, 0x3e, 0x80, 
  0x2f, 0x0c, 0xa9, 0xfe, 0x64, 0x53, 0x69, 0x7a
};

//------------------------------------------------------------------------
// Decrypt
//------------------------------------------------------------------------

GBool Decrypt::makeFileKey(int encVersion, int encRevision, int keyLength,
			   GooString *ownerKey, GooString *userKey,
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			   GooString *ownerEnc, GooString *userEnc,
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			   int permissions, GooString *fileID,
			   GooString *ownerPassword, GooString *userPassword,
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			   Guchar *fileKey, GBool encryptMetadata,
			   GBool *ownerPasswordOk) {
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  DecryptAES256State state;
  Guchar test[127 + 56], test2[32];
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  GooString *userPassword2;
  Guchar fState[256];
  Guchar tmpKey[16];
  Guchar fx, fy;
  int len, i, j;

  *ownerPasswordOk = gFalse;
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  if (encRevision == 5) {

    // check the owner password
    if (ownerPassword) {
      //~ this is supposed to convert the password to UTF-8 using "SASLprep"
      len = ownerPassword->getLength();
      if (len > 127) {
	len = 127;
      }
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      memcpy(test, ownerPassword->getCString(), len);
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      memcpy(test + len, ownerKey->getCString() + 32, 8);
      memcpy(test + len + 8, userKey->getCString(), 48);
      sha256(test, len + 56, test);
      if (!memcmp(test, ownerKey->getCString(), 32)) {

	// compute the file key from the owner password
	memcpy(test, ownerPassword->getCString(), len);
	memcpy(test + len, ownerKey->getCString() + 40, 8);
	memcpy(test + len + 8, userKey->getCString(), 48);
	sha256(test, len + 56, test);
	aes256KeyExpansion(&state, test, 32);
	for (i = 0; i < 16; ++i) {
	  state.cbc[i] = 0;
	}
	aes256DecryptBlock(&state, (Guchar *)ownerEnc->getCString(), gFalse);
	memcpy(fileKey, state.buf, 16);
	aes256DecryptBlock(&state, (Guchar *)ownerEnc->getCString() + 16,
			   gFalse);
	memcpy(fileKey + 16, state.buf, 16);

	*ownerPasswordOk = gTrue;
	return gTrue;
      }
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    }
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    // check the user password
    if (userPassword) {
      //~ this is supposed to convert the password to UTF-8 using "SASLprep"
      len = userPassword->getLength();
      if (len > 127) {
	len = 127;
      }
      memcpy(test, userPassword->getCString(), len);
      memcpy(test + len, userKey->getCString() + 32, 8);
      sha256(test, len + 8, test);
      if (!memcmp(test, userKey->getCString(), 32)) {

	// compute the file key from the user password
	memcpy(test, userPassword->getCString(), len);
	memcpy(test + len, userKey->getCString() + 40, 8);
	sha256(test, len + 8, test);
	aes256KeyExpansion(&state, test, 32);
	for (i = 0; i < 16; ++i) {
	  state.cbc[i] = 0;
	}
	aes256DecryptBlock(&state, (Guchar *)userEnc->getCString(), gFalse);
	memcpy(fileKey, state.buf, 16);
	aes256DecryptBlock(&state, (Guchar *)userEnc->getCString() + 16,
			   gFalse);
	memcpy(fileKey + 16, state.buf, 16);

	return gTrue; 
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      }
    }
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    return gFalse;
  } else {

    // try using the supplied owner password to generate the user password
    if (ownerPassword) {
      len = ownerPassword->getLength();
      if (len < 32) {
	memcpy(test, ownerPassword->getCString(), len);
	memcpy(test + len, passwordPad, 32 - len);
      } else {
	memcpy(test, ownerPassword->getCString(), 32);
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      }
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      md5(test, 32, test);
      if (encRevision == 3) {
	for (i = 0; i < 50; ++i) {
	  md5(test, keyLength, test);
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	}
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      }
      if (encRevision == 2) {
	rc4InitKey(test, keyLength, fState);
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	fx = fy = 0;
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	for (i = 0; i < 32; ++i) {
	  test2[i] = rc4DecryptByte(fState, &fx, &fy, ownerKey->getChar(i));
	}
      } else {
	memcpy(test2, ownerKey->getCString(), 32);
	for (i = 19; i >= 0; --i) {
	  for (j = 0; j < keyLength; ++j) {
	    tmpKey[j] = test[j] ^ i;
	  }
	  rc4InitKey(tmpKey, keyLength, fState);
	  fx = fy = 0;
	  for (j = 0; j < 32; ++j) {
	    test2[j] = rc4DecryptByte(fState, &fx, &fy, test2[j]);
	  }
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	}
      }
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      userPassword2 = new GooString((char *)test2, 32);
      if (makeFileKey2(encVersion, encRevision, keyLength, ownerKey, userKey,
		       permissions, fileID, userPassword2, fileKey,
		       encryptMetadata)) {
	*ownerPasswordOk = gTrue;
	delete userPassword2;
	return gTrue;
      }
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      delete userPassword2;
    }

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    // try using the supplied user password
    return makeFileKey2(encVersion, encRevision, keyLength, ownerKey, userKey,
			permissions, fileID, userPassword, fileKey,
			encryptMetadata);
  }
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}

GBool Decrypt::makeFileKey2(int encVersion, int encRevision, int keyLength,
			    GooString *ownerKey, GooString *userKey,
			    int permissions, GooString *fileID,
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			    GooString *userPassword, Guchar *fileKey,
			    GBool encryptMetadata) {
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  Guchar *buf;
  Guchar test[32];
  Guchar fState[256];
  Guchar tmpKey[16];
  Guchar fx, fy;
  int len, i, j;
  GBool ok;

  // generate file key
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  buf = (Guchar *)gmalloc(72 + fileID->getLength());
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  if (userPassword) {
    len = userPassword->getLength();
    if (len < 32) {
      memcpy(buf, userPassword->getCString(), len);
      memcpy(buf + len, passwordPad, 32 - len);
    } else {
      memcpy(buf, userPassword->getCString(), 32);
    }
  } else {
    memcpy(buf, passwordPad, 32);
  }
  memcpy(buf + 32, ownerKey->getCString(), 32);
  buf[64] = permissions & 0xff;
  buf[65] = (permissions >> 8) & 0xff;
  buf[66] = (permissions >> 16) & 0xff;
  buf[67] = (permissions >> 24) & 0xff;
  memcpy(buf + 68, fileID->getCString(), fileID->getLength());
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  len = 68 + fileID->getLength();
  if (!encryptMetadata) {
    buf[len++] = 0xff;
    buf[len++] = 0xff;
    buf[len++] = 0xff;
    buf[len++] = 0xff;
  }
  md5(buf, len, fileKey);
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  if (encRevision == 3) {
    for (i = 0; i < 50; ++i) {
      md5(fileKey, keyLength, fileKey);
    }
  }

  // test user password
  if (encRevision == 2) {
    rc4InitKey(fileKey, keyLength, fState);
    fx = fy = 0;
    for (i = 0; i < 32; ++i) {
      test[i] = rc4DecryptByte(fState, &fx, &fy, userKey->getChar(i));
    }
    ok = memcmp(test, passwordPad, 32) == 0;
  } else if (encRevision == 3) {
    memcpy(test, userKey->getCString(), 32);
    for (i = 19; i >= 0; --i) {
      for (j = 0; j < keyLength; ++j) {
	tmpKey[j] = fileKey[j] ^ i;
      }
      rc4InitKey(tmpKey, keyLength, fState);
      fx = fy = 0;
      for (j = 0; j < 32; ++j) {
	test[j] = rc4DecryptByte(fState, &fx, &fy, test[j]);
      }
    }
    memcpy(buf, passwordPad, 32);
    memcpy(buf + 32, fileID->getCString(), fileID->getLength());
    md5(buf, 32 + fileID->getLength(), buf);
    ok = memcmp(test, buf, 16) == 0;
  } else {
    ok = gFalse;
  }

  gfree(buf);
  return ok;
}

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//------------------------------------------------------------------------
// DecryptStream
//------------------------------------------------------------------------

DecryptStream::DecryptStream(Stream *strA, Guchar *fileKey,
			     CryptAlgorithm algoA, int keyLength,
			     int objNum, int objGen):
  FilterStream(strA)
{
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  int i;
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  algo = algoA;

  // construct object key
  for (i = 0; i < keyLength; ++i) {
    objKey[i] = fileKey[i];
  }
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  switch (algo) {
  case cryptRC4:
    objKey[keyLength] = objNum & 0xff;
    objKey[keyLength + 1] = (objNum >> 8) & 0xff;
    objKey[keyLength + 2] = (objNum >> 16) & 0xff;
    objKey[keyLength + 3] = objGen & 0xff;
    objKey[keyLength + 4] = (objGen >> 8) & 0xff;
    md5(objKey, keyLength + 5, objKey);
    if ((objKeyLength = keyLength + 5) > 16) {
      objKeyLength = 16;
    }
    break;
  case cryptAES:
    objKey[keyLength] = objNum & 0xff;
    objKey[keyLength + 1] = (objNum >> 8) & 0xff;
    objKey[keyLength + 2] = (objNum >> 16) & 0xff;
    objKey[keyLength + 3] = objGen & 0xff;
    objKey[keyLength + 4] = (objGen >> 8) & 0xff;
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    objKey[keyLength + 5] = 0x73; // 's'
    objKey[keyLength + 6] = 0x41; // 'A'
    objKey[keyLength + 7] = 0x6c; // 'l'
    objKey[keyLength + 8] = 0x54; // 'T'
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    md5(objKey, keyLength + 9, objKey);
    if ((objKeyLength = keyLength + 5) > 16) {
      objKeyLength = 16;
    }
    break;
  case cryptAES256:
    objKeyLength = keyLength;
    break;
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  }
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  charactersRead = 0;
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}

DecryptStream::~DecryptStream() {
  delete str;
}

void DecryptStream::reset() {
  int i;

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  charactersRead = 0;
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  str->reset();
  switch (algo) {
  case cryptRC4:
    state.rc4.x = state.rc4.y = 0;
    rc4InitKey(objKey, objKeyLength, state.rc4.state);
    state.rc4.buf = EOF;
    break;
  case cryptAES:
    aesKeyExpansion(&state.aes, objKey, objKeyLength);
    for (i = 0; i < 16; ++i) {
      state.aes.cbc[i] = str->getChar();
    }
    state.aes.bufIdx = 16;
    break;
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  case cryptAES256:
    aes256KeyExpansion(&state.aes256, objKey, objKeyLength);
    for (i = 0; i < 16; ++i) {
      state.aes256.cbc[i] = str->getChar();
    }
    state.aes256.bufIdx = 16;
    break;
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  }
}

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int DecryptStream::getPos() {
  return charactersRead;
}

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int DecryptStream::getChar() {
  Guchar in[16];
  int c, i;

  c = EOF; // make gcc happy
  switch (algo) {
  case cryptRC4:
    if (state.rc4.buf == EOF) {
      c = str->getChar();
      if (c != EOF) {
	state.rc4.buf = rc4DecryptByte(state.rc4.state, &state.rc4.x,
				       &state.rc4.y, (Guchar)c);
      }
    }
    c = state.rc4.buf;
    state.rc4.buf = EOF;
    break;
  case cryptAES:
    if (state.aes.bufIdx == 16) {
      for (i = 0; i < 16; ++i) {
	if ((c = str->getChar()) == EOF) {
	  return EOF;
	}
	in[i] = (Guchar)c;
      }
      aesDecryptBlock(&state.aes, in, str->lookChar() == EOF);
    }
    if (state.aes.bufIdx == 16) {
      c = EOF;
    } else {
      c = state.aes.buf[state.aes.bufIdx++];
    }
    break;
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  case cryptAES256:
    if (state.aes256.bufIdx == 16) {
      for (i = 0; i < 16; ++i) {
	if ((c = str->getChar()) == EOF) {
	  return EOF;
	}
	in[i] = (Guchar)c;
      }
      aes256DecryptBlock(&state.aes256, in, str->lookChar() == EOF);
    }
    if (state.aes256.bufIdx == 16) {
      c = EOF;
    } else {
      c = state.aes256.buf[state.aes256.bufIdx++];
    }
    break;
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  }
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  if (c != EOF)
    charactersRead++;
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  return c;
}

int DecryptStream::lookChar() {
  Guchar in[16];
  int c, i;

  c = EOF; // make gcc happy
  switch (algo) {
  case cryptRC4:
    if (state.rc4.buf == EOF) {
      c = str->getChar();
      if (c != EOF) {
	state.rc4.buf = rc4DecryptByte(state.rc4.state, &state.rc4.x,
				       &state.rc4.y, (Guchar)c);
      }
    }
    c = state.rc4.buf;
    break;
  case cryptAES:
    if (state.aes.bufIdx == 16) {
      for (i = 0; i < 16; ++i) {
	if ((c = str->getChar()) == EOF) {
	  return EOF;
	}
	in[i] = c;
      }
      aesDecryptBlock(&state.aes, in, str->lookChar() == EOF);
    }
    if (state.aes.bufIdx == 16) {
      c = EOF;
    } else {
      c = state.aes.buf[state.aes.bufIdx];
    }
    break;
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  case cryptAES256:
    if (state.aes256.bufIdx == 16) {
      for (i = 0; i < 16; ++i) {
	if ((c = str->getChar()) == EOF) {
	  return EOF;
	}
	in[i] = c;
      }
      aes256DecryptBlock(&state.aes256, in, str->lookChar() == EOF);
    }
    if (state.aes256.bufIdx == 16) {
      c = EOF;
    } else {
      c = state.aes256.buf[state.aes256.bufIdx];
    }
    break;
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  }
  return c;
}

GBool DecryptStream::isBinary(GBool last) {
  return str->isBinary(last);
}

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//------------------------------------------------------------------------
// RC4-compatible decryption
//------------------------------------------------------------------------

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void rc4InitKey(Guchar *key, int keyLen, Guchar *state) {
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  Guchar index1, index2;
  Guchar t;
  int i;

  for (i = 0; i < 256; ++i)
    state[i] = i;
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  if (unlikely(keyLen == 0))
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    return;

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  index1 = index2 = 0;
  for (i = 0; i < 256; ++i) {
    index2 = (key[index1] + state[i] + index2) % 256;
    t = state[i];
    state[i] = state[index2];
    state[index2] = t;
    index1 = (index1 + 1) % keyLen;
  }
}

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Guchar rc4DecryptByte(Guchar *state, Guchar *x, Guchar *y, Guchar c) {
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  Guchar x1, y1, tx, ty;

  x1 = *x = (*x + 1) % 256;
  y1 = *y = (state[*x] + *y) % 256;
  tx = state[x1];
  ty = state[y1];
  state[x1] = ty;
  state[y1] = tx;
  return c ^ state[(tx + ty) % 256];
}

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//------------------------------------------------------------------------
// AES decryption
//------------------------------------------------------------------------

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static const Guchar sbox[256] = {
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  0x63, 0x7c, 0x77, 0x7b, 0xf2, 0x6b, 0x6f, 0xc5, 0x30, 0x01, 0x67, 0x2b, 0xfe, 0xd7, 0xab, 0x76,
  0xca, 0x82, 0xc9, 0x7d, 0xfa, 0x59, 0x47, 0xf0, 0xad, 0xd4, 0xa2, 0xaf, 0x9c, 0xa4, 0x72, 0xc0,
  0xb7, 0xfd, 0x93, 0x26, 0x36, 0x3f, 0xf7, 0xcc, 0x34, 0xa5, 0xe5, 0xf1, 0x71, 0xd8, 0x31, 0x15,
  0x04, 0xc7, 0x23, 0xc3, 0x18, 0x96, 0x05, 0x9a, 0x07, 0x12, 0x80, 0xe2, 0xeb, 0x27, 0xb2, 0x75,
  0x09, 0x83, 0x2c, 0x1a, 0x1b, 0x6e, 0x5a, 0xa0, 0x52, 0x3b, 0xd6, 0xb3, 0x29, 0xe3, 0x2f, 0x84,
  0x53, 0xd1, 0x00, 0xed, 0x20, 0xfc, 0xb1, 0x5b, 0x6a, 0xcb, 0xbe, 0x39, 0x4a, 0x4c, 0x58, 0xcf,
  0xd0, 0xef, 0xaa, 0xfb, 0x43, 0x4d, 0x33, 0x85, 0x45, 0xf9, 0x02, 0x7f, 0x50, 0x3c, 0x9f, 0xa8,
  0x51, 0xa3, 0x40, 0x8f, 0x92, 0x9d, 0x38, 0xf5, 0xbc, 0xb6, 0xda, 0x21, 0x10, 0xff, 0xf3, 0xd2,
  0xcd, 0x0c, 0x13, 0xec, 0x5f, 0x97, 0x44, 0x17, 0xc4, 0xa7, 0x7e, 0x3d, 0x64, 0x5d, 0x19, 0x73,
  0x60, 0x81, 0x4f, 0xdc, 0x22, 0x2a, 0x90, 0x88, 0x46, 0xee, 0xb8, 0x14, 0xde, 0x5e, 0x0b, 0xdb,
  0xe0, 0x32, 0x3a, 0x0a, 0x49, 0x06, 0x24, 0x5c, 0xc2, 0xd3, 0xac, 0x62, 0x91, 0x95, 0xe4, 0x79,
  0xe7, 0xc8, 0x37, 0x6d, 0x8d, 0xd5, 0x4e, 0xa9, 0x6c, 0x56, 0xf4, 0xea, 0x65, 0x7a, 0xae, 0x08,
  0xba, 0x78, 0x25, 0x2e, 0x1c, 0xa6, 0xb4, 0xc6, 0xe8, 0xdd, 0x74, 0x1f, 0x4b, 0xbd, 0x8b, 0x8a,
  0x70, 0x3e, 0xb5, 0x66, 0x48, 0x03, 0xf6, 0x0e, 0x61, 0x35, 0x57, 0xb9, 0x86, 0xc1, 0x1d, 0x9e,
  0xe1, 0xf8, 0x98, 0x11, 0x69, 0xd9, 0x8e, 0x94, 0x9b, 0x1e, 0x87, 0xe9, 0xce, 0x55, 0x28, 0xdf,
  0x8c, 0xa1, 0x89, 0x0d, 0xbf, 0xe6, 0x42, 0x68, 0x41, 0x99, 0x2d, 0x0f, 0xb0, 0x54, 0xbb, 0x16
};

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static const Guchar invSbox[256] = {
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  0x52, 0x09, 0x6a, 0xd5, 0x30, 0x36, 0xa5, 0x38, 0xbf, 0x40, 0xa3, 0x9e, 0x81, 0xf3, 0xd7, 0xfb,
  0x7c, 0xe3, 0x39, 0x82, 0x9b, 0x2f, 0xff, 0x87, 0x34, 0x8e, 0x43, 0x44, 0xc4, 0xde, 0xe9, 0xcb,
  0x54, 0x7b, 0x94, 0x32, 0xa6, 0xc2, 0x23, 0x3d, 0xee, 0x4c, 0x95, 0x0b, 0x42, 0xfa, 0xc3, 0x4e,
  0x08, 0x2e, 0xa1, 0x66, 0x28, 0xd9, 0x24, 0xb2, 0x76, 0x5b, 0xa2, 0x49, 0x6d, 0x8b, 0xd1, 0x25,
  0x72, 0xf8, 0xf6, 0x64, 0x86, 0x68, 0x98, 0x16, 0xd4, 0xa4, 0x5c, 0xcc, 0x5d, 0x65, 0xb6, 0x92,
  0x6c, 0x70, 0x48, 0x50, 0xfd, 0xed, 0xb9, 0xda, 0x5e, 0x15, 0x46, 0x57, 0xa7, 0x8d, 0x9d, 0x84,
  0x90, 0xd8, 0xab, 0x00, 0x8c, 0xbc, 0xd3, 0x0a, 0xf7, 0xe4, 0x58, 0x05, 0xb8, 0xb3, 0x45, 0x06,
  0xd0, 0x2c, 0x1e, 0x8f, 0xca, 0x3f, 0x0f, 0x02, 0xc1, 0xaf, 0xbd, 0x03, 0x01, 0x13, 0x8a, 0x6b,
  0x3a, 0x91, 0x11, 0x41, 0x4f, 0x67, 0xdc, 0xea, 0x97, 0xf2, 0xcf, 0xce, 0xf0, 0xb4, 0xe6, 0x73,
  0x96, 0xac, 0x74, 0x22, 0xe7, 0xad, 0x35, 0x85, 0xe2, 0xf9, 0x37, 0xe8, 0x1c, 0x75, 0xdf, 0x6e,
  0x47, 0xf1, 0x1a, 0x71, 0x1d, 0x29, 0xc5, 0x89, 0x6f, 0xb7, 0x62, 0x0e, 0xaa, 0x18, 0xbe, 0x1b,
  0xfc, 0x56, 0x3e, 0x4b, 0xc6, 0xd2, 0x79, 0x20, 0x9a, 0xdb, 0xc0, 0xfe, 0x78, 0xcd, 0x5a, 0xf4,
  0x1f, 0xdd, 0xa8, 0x33, 0x88, 0x07, 0xc7, 0x31, 0xb1, 0x12, 0x10, 0x59, 0x27, 0x80, 0xec, 0x5f,
  0x60, 0x51, 0x7f, 0xa9, 0x19, 0xb5, 0x4a, 0x0d, 0x2d, 0xe5, 0x7a, 0x9f, 0x93, 0xc9, 0x9c, 0xef,
  0xa0, 0xe0, 0x3b, 0x4d, 0xae, 0x2a, 0xf5, 0xb0, 0xc8, 0xeb, 0xbb, 0x3c, 0x83, 0x53, 0x99, 0x61,
  0x17, 0x2b, 0x04, 0x7e, 0xba, 0x77, 0xd6, 0x26, 0xe1, 0x69, 0x14, 0x63, 0x55, 0x21, 0x0c, 0x7d
};

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static const Guint rcon[11] = {
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  0x00000000, // unused
  0x01000000,
  0x02000000,
  0x04000000,
  0x08000000,
  0x10000000,
  0x20000000,
  0x40000000,
  0x80000000,
  0x1b000000,
  0x36000000
};

static inline Guint subWord(Guint x) {
  return (sbox[x >> 24] << 24)
         | (sbox[(x >> 16) & 0xff] << 16)
         | (sbox[(x >> 8) & 0xff] << 8)
         | sbox[x & 0xff];
}

static inline Guint rotWord(Guint x) {
  return ((x << 8) & 0xffffffff) | (x >> 24);
}

static inline void invSubBytes(Guchar *state) {
  int i;

  for (i = 0; i < 16; ++i) {
    state[i] = invSbox[state[i]];
  }
}

static inline void invShiftRows(Guchar *state) {
  Guchar t;

  t = state[7];
  state[7] = state[6];
  state[6] = state[5];
  state[5] = state[4];
  state[4] = t;

  t = state[8];
  state[8] = state[10];
  state[10] = t;
  t = state[9];
  state[9] = state[11];
  state[11] = t;

  t = state[12];
  state[12] = state[13];
  state[13] = state[14];
  state[14] = state[15];
  state[15] = t;
}

// {09} \cdot s
static inline Guchar mul09(Guchar s) {
  Guchar s2, s4, s8;

  s2 = (s & 0x80) ? ((s << 1) ^ 0x1b) : (s << 1);
  s4 = (s2 & 0x80) ? ((s2 << 1) ^ 0x1b) : (s2 << 1);
  s8 = (s4 & 0x80) ? ((s4 << 1) ^ 0x1b) : (s4 << 1);
  return s ^ s8;
}

// {0b} \cdot s
static inline Guchar mul0b(Guchar s) {
  Guchar s2, s4, s8;

  s2 = (s & 0x80) ? ((s << 1) ^ 0x1b) : (s << 1);
  s4 = (s2 & 0x80) ? ((s2 << 1) ^ 0x1b) : (s2 << 1);
  s8 = (s4 & 0x80) ? ((s4 << 1) ^ 0x1b) : (s4 << 1);
  return s ^ s2 ^ s8;
}

// {0d} \cdot s
static inline Guchar mul0d(Guchar s) {
  Guchar s2, s4, s8;

  s2 = (s & 0x80) ? ((s << 1) ^ 0x1b) : (s << 1);
  s4 = (s2 & 0x80) ? ((s2 << 1) ^ 0x1b) : (s2 << 1);
  s8 = (s4 & 0x80) ? ((s4 << 1) ^ 0x1b) : (s4 << 1);
  return s ^ s4 ^ s8;
}

// {0e} \cdot s
static inline Guchar mul0e(Guchar s) {
  Guchar s2, s4, s8;

  s2 = (s & 0x80) ? ((s << 1) ^ 0x1b) : (s << 1);
  s4 = (s2 & 0x80) ? ((s2 << 1) ^ 0x1b) : (s2 << 1);
  s8 = (s4 & 0x80) ? ((s4 << 1) ^ 0x1b) : (s4 << 1);
  return s2 ^ s4 ^ s8;
}

static inline void invMixColumns(Guchar *state) {
  int c;
  Guchar s0, s1, s2, s3;

  for (c = 0; c < 4; ++c) {
    s0 = state[c];
    s1 = state[4+c];
    s2 = state[8+c];
    s3 = state[12+c];
    state[c] =    mul0e(s0) ^ mul0b(s1) ^ mul0d(s2) ^ mul09(s3);
    state[4+c] =  mul09(s0) ^ mul0e(s1) ^ mul0b(s2) ^ mul0d(s3);
    state[8+c] =  mul0d(s0) ^ mul09(s1) ^ mul0e(s2) ^ mul0b(s3);
    state[12+c] = mul0b(s0) ^ mul0d(s1) ^ mul09(s2) ^ mul0e(s3);
  }
}

static inline void invMixColumnsW(Guint *w) {
  int c;
  Guchar s0, s1, s2, s3;

  for (c = 0; c < 4; ++c) {
    s0 = w[c] >> 24;
    s1 = w[c] >> 16;
    s2 = w[c] >> 8;
    s3 = w[c];
    w[c] = ((mul0e(s0) ^ mul0b(s1) ^ mul0d(s2) ^ mul09(s3)) << 24)
           | ((mul09(s0) ^ mul0e(s1) ^ mul0b(s2) ^ mul0d(s3)) << 16)
           | ((mul0d(s0) ^ mul09(s1) ^ mul0e(s2) ^ mul0b(s3)) << 8)
           | (mul0b(s0) ^ mul0d(s1) ^ mul09(s2) ^ mul0e(s3));
  }
}

static inline void addRoundKey(Guchar *state, Guint *w) {
  int c;

  for (c = 0; c < 4; ++c) {
    state[c] ^= w[c] >> 24;
    state[4+c] ^= w[c] >> 16;
    state[8+c] ^= w[c] >> 8;
    state[12+c] ^= w[c];
  }
}

static void aesKeyExpansion(DecryptAESState *s,
			    Guchar *objKey, int /*objKeyLen*/) {
  Guint temp;
  int i, round;

  //~ this assumes objKeyLen == 16

  for (i = 0; i < 4; ++i) {
    s->w[i] = (objKey[4*i] << 24) + (objKey[4*i+1] << 16) +
              (objKey[4*i+2] << 8) + objKey[4*i+3];
  }
  for (i = 4; i < 44; ++i) {
    temp = s->w[i-1];
    if (!(i & 3)) {
      temp = subWord(rotWord(temp)) ^ rcon[i/4];
    }
    s->w[i] = s->w[i-4] ^ temp;
  }
  for (round = 1; round <= 9; ++round) {
    invMixColumnsW(&s->w[round * 4]);
  }
}

static void aesDecryptBlock(DecryptAESState *s, Guchar *in, GBool last) {
  int c, round, n, i;

  // initial state
  for (c = 0; c < 4; ++c) {
    s->state[c] = in[4*c];
    s->state[4+c] = in[4*c+1];
    s->state[8+c] = in[4*c+2];
    s->state[12+c] = in[4*c+3];
  }

  // round 0
  addRoundKey(s->state, &s->w[10 * 4]);

  // rounds 1-9
  for (round = 9; round >= 1; --round) {
    invSubBytes(s->state);
    invShiftRows(s->state);
    invMixColumns(s->state);
    addRoundKey(s->state, &s->w[round * 4]);
  }

  // round 10
  invSubBytes(s->state);
  invShiftRows(s->state);
  addRoundKey(s->state, &s->w[0]);

  // CBC
  for (c = 0; c < 4; ++c) {
    s->buf[4*c] = s->state[c] ^ s->cbc[4*c];
    s->buf[4*c+1] = s->state[4+c] ^ s->cbc[4*c+1];
    s->buf[4*c+2] = s->state[8+c] ^ s->cbc[4*c+2];
    s->buf[4*c+3] = s->state[12+c] ^ s->cbc[4*c+3];
  }

  // save the input block for the next CBC
  for (i = 0; i < 16; ++i) {
    s->cbc[i] = in[i];
  }

  // remove padding
  s->bufIdx = 0;
  if (last) {
    n = s->buf[15];
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    if (n < 1 || n > 16) { // this should never happen
      n = 16;
    }
    for (i = 15; i >= n; --i) {
      s->buf[i] = s->buf[i-n];
    }
    s->bufIdx = n;
  }
}

//------------------------------------------------------------------------
// AES-256 decryption
//------------------------------------------------------------------------

static void aes256KeyExpansion(DecryptAES256State *s,
			       Guchar *objKey, int objKeyLen) {
  Guint temp;
  int i, round;

  //~ this assumes objKeyLen == 32

  for (i = 0; i < 8; ++i) {
    s->w[i] = (objKey[4*i] << 24) + (objKey[4*i+1] << 16) +
              (objKey[4*i+2] << 8) + objKey[4*i+3];
  }
  for (i = 8; i < 60; ++i) {
    temp = s->w[i-1];
    if ((i & 7) == 0) {
      temp = subWord(rotWord(temp)) ^ rcon[i/8];
    } else if ((i & 7) == 4) {
      temp = subWord(temp);
    }
    s->w[i] = s->w[i-8] ^ temp;
  }
  for (round = 1; round <= 13; ++round) {
    invMixColumnsW(&s->w[round * 4]);
  }
}

static void aes256DecryptBlock(DecryptAES256State *s, Guchar *in, GBool last) {
  int c, round, n, i;

  // initial state
  for (c = 0; c < 4; ++c) {
    s->state[c] = in[4*c];
    s->state[4+c] = in[4*c+1];
    s->state[8+c] = in[4*c+2];
    s->state[12+c] = in[4*c+3];
  }

  // round 0
  addRoundKey(s->state, &s->w[14 * 4]);

  // rounds 13-1
  for (round = 13; round >= 1; --round) {
    invSubBytes(s->state);
    invShiftRows(s->state);
    invMixColumns(s->state);
    addRoundKey(s->state, &s->w[round * 4]);
  }

  // round 14
  invSubBytes(s->state);
  invShiftRows(s->state);
  addRoundKey(s->state, &s->w[0]);

  // CBC
  for (c = 0; c < 4; ++c) {
    s->buf[4*c] = s->state[c] ^ s->cbc[4*c];
    s->buf[4*c+1] = s->state[4+c] ^ s->cbc[4*c+1];
    s->buf[4*c+2] = s->state[8+c] ^ s->cbc[4*c+2];
    s->buf[4*c+3] = s->state[12+c] ^ s->cbc[4*c+3];
  }

  // save the input block for the next CBC
  for (i = 0; i < 16; ++i) {
    s->cbc[i] = in[i];
  }

  // remove padding
  s->bufIdx = 0;
  if (last) {
    n = s->buf[15];
    if (n < 1 || n > 16) { // this should never happen
      n = 16;
    }
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    for (i = 15; i >= n; --i) {
      s->buf[i] = s->buf[i-n];
    }
    s->bufIdx = n;
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    if (n > 16)
    {
      error(-1, "Reducing bufIdx from %d to 16 to not crash", n);
      s->bufIdx = 16;
    }
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  }
}

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//------------------------------------------------------------------------
// MD5 message digest
//------------------------------------------------------------------------

// this works around a bug in older Sun compilers
static inline Gulong rotateLeft(Gulong x, int r) {
  x &= 0xffffffff;
  return ((x << r) | (x >> (32 - r))) & 0xffffffff;
}

static inline Gulong md5Round1(Gulong a, Gulong b, Gulong c, Gulong d,
			       Gulong Xk,  Gulong s, Gulong Ti) {
  return b + rotateLeft((a + ((b & c) | (~b & d)) + Xk + Ti), s);
}

static inline Gulong md5Round2(Gulong a, Gulong b, Gulong c, Gulong d,
			       Gulong Xk,  Gulong s, Gulong Ti) {
  return b + rotateLeft((a + ((b & d) | (c & ~d)) + Xk + Ti), s);
}

static inline Gulong md5Round3(Gulong a, Gulong b, Gulong c, Gulong d,
			       Gulong Xk,  Gulong s, Gulong Ti) {
  return b + rotateLeft((a + (b ^ c ^ d) + Xk + Ti), s);
}

static inline Gulong md5Round4(Gulong a, Gulong b, Gulong c, Gulong d,
			       Gulong Xk,  Gulong s, Gulong Ti) {
  return b + rotateLeft((a + (c ^ (b | ~d)) + Xk + Ti), s);
}

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void md5(Guchar *msg, int msgLen, Guchar *digest) {
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  Gulong x[16];
  Gulong a, b, c, d, aa, bb, cc, dd;
  int n64;
  int i, j, k;

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  // sanity check
  if (msgLen < 0) {
    return;
  }

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  // compute number of 64-byte blocks
  // (length + pad byte (0x80) + 8 bytes for length)
  n64 = (msgLen + 1 + 8 + 63) / 64;

  // initialize a, b, c, d
  a = 0x67452301;
  b = 0xefcdab89;
  c = 0x98badcfe;
  d = 0x10325476;

  // loop through blocks
  k = 0;
  for (i = 0; i < n64; ++i) {

    // grab a 64-byte block
    for (j = 0; j < 16 && k < msgLen - 3; ++j, k += 4)
      x[j] = (((((msg[k+3] << 8) + msg[k+2]) << 8) + msg[k+1]) << 8) + msg[k];
    if (i == n64 - 1) {
      if (k == msgLen - 3)
	x[j] = 0x80000000 + (((msg[k+2] << 8) + msg[k+1]) << 8) + msg[k];
      else if (k == msgLen - 2)
	x[j] = 0x800000 + (msg[k+1] << 8) + msg[k];
      else if (k == msgLen - 1)
	x[j] = 0x8000 + msg[k];
      else
	x[j] = 0x80;
      ++j;
      while (j < 16)
	x[j++] = 0;
      x[14] = msgLen << 3;
    }

    // save a, b, c, d
    aa = a;
    bb = b;
    cc = c;
    dd = d;

    // round 1
    a = md5Round1(a, b, c, d, x[0],   7, 0xd76aa478);
    d = md5Round1(d, a, b, c, x[1],  12, 0xe8c7b756);
    c = md5Round1(c, d, a, b, x[2],  17, 0x242070db);
    b = md5Round1(b, c, d, a, x[3],  22, 0xc1bdceee);
    a = md5Round1(a, b, c, d, x[4],   7, 0xf57c0faf);
    d = md5Round1(d, a, b, c, x[5],  12, 0x4787c62a);
    c = md5Round1(c, d, a, b, x[6],  17, 0xa8304613);
    b = md5Round1(b, c, d, a, x[7],  22, 0xfd469501);
    a = md5Round1(a, b, c, d, x[8],   7, 0x698098d8);
    d = md5Round1(d, a, b, c, x[9],  12, 0x8b44f7af);
    c = md5Round1(c, d, a, b, x[10], 17, 0xffff5bb1);
    b = md5Round1(b, c, d, a, x[11], 22, 0x895cd7be);
    a = md5Round1(a, b, c, d, x[12],  7, 0x6b901122);
    d = md5Round1(d, a, b, c, x[13], 12, 0xfd987193);
    c = md5Round1(c, d, a, b, x[14], 17, 0xa679438e);
    b = md5Round1(b, c, d, a, x[15], 22, 0x49b40821);

    // round 2
    a = md5Round2(a, b, c, d, x[1],   5, 0xf61e2562);
    d = md5Round2(d, a, b, c, x[6],   9, 0xc040b340);
    c = md5Round2(c, d, a, b, x[11], 14, 0x265e5a51);
    b = md5Round2(b, c, d, a, x[0],  20, 0xe9b6c7aa);
    a = md5Round2(a, b, c, d, x[5],   5, 0xd62f105d);
    d = md5Round2(d, a, b, c, x[10],  9, 0x02441453);
    c = md5Round2(c, d, a, b, x[15], 14, 0xd8a1e681);
    b = md5Round2(b, c, d, a, x[4],  20, 0xe7d3fbc8);
    a = md5Round2(a, b, c, d, x[9],   5, 0x21e1cde6);
    d = md5Round2(d, a, b, c, x[14],  9, 0xc33707d6);
    c = md5Round2(c, d, a, b, x[3],  14, 0xf4d50d87);
    b = md5Round2(b, c, d, a, x[8],  20, 0x455a14ed);
    a = md5Round2(a, b, c, d, x[13],  5, 0xa9e3e905);
    d = md5Round2(d, a, b, c, x[2],   9, 0xfcefa3f8);
    c = md5Round2(c, d, a, b, x[7],  14, 0x676f02d9);
    b = md5Round2(b, c, d, a, x[12], 20, 0x8d2a4c8a);

    // round 3
    a = md5Round3(a, b, c, d, x[5],   4, 0xfffa3942);
    d = md5Round3(d, a, b, c, x[8],  11, 0x8771f681);
    c = md5Round3(c, d, a, b, x[11], 16, 0x6d9d6122);
    b = md5Round3(b, c, d, a, x[14], 23, 0xfde5380c);
    a = md5Round3(a, b, c, d, x[1],   4, 0xa4beea44);
    d = md5Round3(d, a, b, c, x[4],  11, 0x4bdecfa9);
    c = md5Round3(c, d, a, b, x[7],  16, 0xf6bb4b60);
    b = md5Round3(b, c, d, a, x[10], 23, 0xbebfbc70);
    a = md5Round3(a, b, c, d, x[13],  4, 0x289b7ec6);
    d = md5Round3(d, a, b, c, x[0],  11, 0xeaa127fa);
    c = md5Round3(c, d, a, b, x[3],  16, 0xd4ef3085);
    b = md5Round3(b, c, d, a, x[6],  23, 0x04881d05);
    a = md5Round3(a, b, c, d, x[9],   4, 0xd9d4d039);
    d = md5Round3(d, a, b, c, x[12], 11, 0xe6db99e5);
    c = md5Round3(c, d, a, b, x[15], 16, 0x1fa27cf8);
    b = md5Round3(b, c, d, a, x[2],  23, 0xc4ac5665);

    // round 4
    a = md5Round4(a, b, c, d, x[0],   6, 0xf4292244);
    d = md5Round4(d, a, b, c, x[7],  10, 0x432aff97);
    c = md5Round4(c, d, a, b, x[14], 15, 0xab9423a7);
    b = md5Round4(b, c, d, a, x[5],  21, 0xfc93a039);
    a = md5Round4(a, b, c, d, x[12],  6, 0x655b59c3);
    d = md5Round4(d, a, b, c, x[3],  10, 0x8f0ccc92);
    c = md5Round4(c, d, a, b, x[10], 15, 0xffeff47d);
    b = md5Round4(b, c, d, a, x[1],  21, 0x85845dd1);
    a = md5Round4(a, b, c, d, x[8],   6, 0x6fa87e4f);
    d = md5Round4(d, a, b, c, x[15], 10, 0xfe2ce6e0);
    c = md5Round4(c, d, a, b, x[6],  15, 0xa3014314);
    b = md5Round4(b, c, d, a, x[13], 21, 0x4e0811a1);
    a = md5Round4(a, b, c, d, x[4],   6, 0xf7537e82);
    d = md5Round4(d, a, b, c, x[11], 10, 0xbd3af235);
    c = md5Round4(c, d, a, b, x[2],  15, 0x2ad7d2bb);
    b = md5Round4(b, c, d, a, x[9],  21, 0xeb86d391);

    // increment a, b, c, d
    a += aa;
    b += bb;
    c += cc;
    d += dd;
  }

  // break digest into bytes
  digest[0] = (Guchar)(a & 0xff);
  digest[1] = (Guchar)((a >>= 8) & 0xff);
  digest[2] = (Guchar)((a >>= 8) & 0xff);
  digest[3] = (Guchar)((a >>= 8) & 0xff);
  digest[4] = (Guchar)(b & 0xff);
  digest[5] = (Guchar)((b >>= 8) & 0xff);
  digest[6] = (Guchar)((b >>= 8) & 0xff);
  digest[7] = (Guchar)((b >>= 8) & 0xff);
  digest[8] = (Guchar)(c & 0xff);
  digest[9] = (Guchar)((c >>= 8) & 0xff);
  digest[10] = (Guchar)((c >>= 8) & 0xff);
  digest[11] = (Guchar)((c >>= 8) & 0xff);
  digest[12] = (Guchar)(d & 0xff);
  digest[13] = (Guchar)((d >>= 8) & 0xff);
  digest[14] = (Guchar)((d >>= 8) & 0xff);
  digest[15] = (Guchar)((d >>= 8) & 0xff);
}
1029 1030 1031 1032 1033 1034 1035 1036 1037 1038 1039 1040 1041 1042 1043 1044 1045 1046 1047 1048 1049 1050 1051 1052 1053 1054 1055 1056 1057 1058 1059 1060 1061 1062 1063 1064 1065 1066 1067 1068 1069 1070 1071 1072 1073 1074 1075 1076 1077 1078 1079 1080 1081 1082 1083 1084 1085 1086 1087 1088 1089 1090 1091 1092 1093 1094 1095 1096 1097 1098 1099 1100 1101 1102 1103 1104 1105 1106 1107 1108 1109 1110 1111 1112 1113 1114 1115 1116 1117 1118 1119 1120 1121 1122 1123 1124 1125 1126 1127 1128 1129 1130 1131 1132 1133 1134 1135 1136 1137 1138 1139 1140 1141 1142 1143 1144 1145 1146 1147 1148 1149 1150 1151 1152 1153 1154 1155 1156 1157 1158 1159 1160 1161 1162 1163 1164 1165 1166 1167 1168 1169 1170 1171 1172 1173 1174 1175 1176 1177 1178 1179 1180 1181 1182 1183 1184 1185

//------------------------------------------------------------------------
// SHA-256 hash
//------------------------------------------------------------------------

static Guint sha256K[64] = {
  0x428a2f98, 0x71374491, 0xb5c0fbcf, 0xe9b5dba5,
  0x3956c25b, 0x59f111f1, 0x923f82a4, 0xab1c5ed5,
  0xd807aa98, 0x12835b01, 0x243185be, 0x550c7dc3,
  0x72be5d74, 0x80deb1fe, 0x9bdc06a7, 0xc19bf174,
  0xe49b69c1, 0xefbe4786, 0x0fc19dc6, 0x240ca1cc,
  0x2de92c6f, 0x4a7484aa, 0x5cb0a9dc, 0x76f988da,
  0x983e5152, 0xa831c66d, 0xb00327c8, 0xbf597fc7,
  0xc6e00bf3, 0xd5a79147, 0x06ca6351, 0x14292967,
  0x27b70a85, 0x2e1b2138, 0x4d2c6dfc, 0x53380d13,
  0x650a7354, 0x766a0abb, 0x81c2c92e, 0x92722c85,
  0xa2bfe8a1, 0xa81a664b, 0xc24b8b70, 0xc76c51a3,
  0xd192e819, 0xd6990624, 0xf40e3585, 0x106aa070,
  0x19a4c116, 0x1e376c08, 0x2748774c, 0x34b0bcb5,
  0x391c0cb3, 0x4ed8aa4a, 0x5b9cca4f, 0x682e6ff3,
  0x748f82ee, 0x78a5636f, 0x84c87814, 0x8cc70208,
  0x90befffa, 0xa4506ceb, 0xbef9a3f7, 0xc67178f2
};

static inline Guint rotr(Guint x, Guint n) {
  return (x >> n) | (x << (32 - n));
}

static inline Guint sha256Ch(Guint x, Guint y, Guint z) {
  return (x & y) ^ (~x & z);
}

static inline Guint sha256Maj(Guint x, Guint y, Guint z) {
  return (x & y) ^ (x & z) ^ (y & z);
}

static inline Guint sha256Sigma0(Guint x) {
  return rotr(x, 2) ^ rotr(x, 13) ^ rotr(x, 22);
}

static inline Guint sha256Sigma1(Guint x) {
  return rotr(x, 6) ^ rotr(x, 11) ^ rotr(x, 25);
}

static inline Guint sha256sigma0(Guint x) {
  return rotr(x, 7) ^ rotr(x, 18) ^ (x >> 3);
}

static inline Guint sha256sigma1(Guint x) {
  return rotr(x, 17) ^ rotr(x, 19) ^ (x >> 10);
}

void sha256HashBlock(Guchar *blk, Guint *H) {
  Guint W[64];
  Guint a, b, c, d, e, f, g, h;
  Guint T1, T2;
  Guint t;

  // 1. prepare the message schedule
  for (t = 0; t < 16; ++t) {
    W[t] = (blk[t*4] << 24) |
           (blk[t*4 + 1] << 16) |
           (blk[t*4 + 2] << 8) |
           blk[t*4 + 3];
  }
  for (t = 16; t < 64; ++t) {
    W[t] = sha256sigma1(W[t-2]) + W[t-7] + sha256sigma0(W[t-15]) + W[t-16];
  }

  // 2. initialize the eight working variables
  a = H[0];
  b = H[1];
  c = H[2];
  d = H[3];
  e = H[4];
  f = H[5];
  g = H[6];
  h = H[7];

  // 3.
  for (t = 0; t < 64; ++t) {
    T1 = h + sha256Sigma1(e) + sha256Ch(e,f,g) + sha256K[t] + W[t];
    T2 = sha256Sigma0(a) + sha256Maj(a,b,c);
    h = g;
    g = f;
    f = e;
    e = d + T1;
    d = c;
    c = b;
    b = a;
    a = T1 + T2;
  }

  // 4. compute the intermediate hash value
  H[0] += a;
  H[1] += b;
  H[2] += c;
  H[3] += d;
  H[4] += e;
  H[5] += f;
  H[6] += g;
  H[7] += h;
}

static void sha256(Guchar *msg, int msgLen, Guchar *hash) {
  Guchar blk[64];
  Guint H[8];
  int blkLen, i;

  H[0] = 0x6a09e667;
  H[1] = 0xbb67ae85;
  H[2] = 0x3c6ef372;
  H[3] = 0xa54ff53a;
  H[4] = 0x510e527f;
  H[5] = 0x9b05688c;
  H[6] = 0x1f83d9ab;
  H[7] = 0x5be0cd19;

  blkLen = 0;
  for (i = 0; i + 64 <= msgLen; i += 64) {
    sha256HashBlock(msg + i, H);
  }
  blkLen = msgLen - i;
  if (blkLen > 0) {
    memcpy(blk, msg + i, blkLen);
  }

  // pad the message
  blk[blkLen++] = 0x80;
  if (blkLen > 56) {
    while (blkLen < 64) {
      blk[blkLen++] = 0;
    }
    sha256HashBlock(blk, H);
    blkLen = 0;
  }
  while (blkLen < 56) {
    blk[blkLen++] = 0;
  }
  blk[56] = 0;
  blk[57] = 0;
  blk[58] = 0;
  blk[59] = 0;
  blk[60] = (Guchar)(msgLen >> 21);
  blk[61] = (Guchar)(msgLen >> 13);
  blk[62] = (Guchar)(msgLen >> 5);
  blk[63] = (Guchar)(msgLen << 3);
  sha256HashBlock(blk, H);

  // copy the output into the buffer (convert words to bytes)
  for (i = 0; i < 8; ++i) {
    hash[i*4]     = (Guchar)(H[i] >> 24);
    hash[i*4 + 1] = (Guchar)(H[i] >> 16);
    hash[i*4 + 2] = (Guchar)(H[i] >> 8);
    hash[i*4 + 3] = (Guchar)H[i];
  }
}