// Copyright 2014 PDFium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

// Original code copyright 2014 Foxit Software Inc. http://www.foxitsoftware.com

#include "core/fpdfapi/fpdf_parser/cpdf_standard_security_handler.h"

#include <time.h>

#include "core/fdrm/crypto/include/fx_crypt.h"
#include "core/fpdfapi/fpdf_parser/cpdf_standard_crypto_handler.h"
#include "core/fpdfapi/fpdf_parser/include/cpdf_array.h"
#include "core/fpdfapi/fpdf_parser/include/cpdf_dictionary.h"
#include "core/fpdfapi/fpdf_parser/include/cpdf_object.h"
#include "core/fpdfapi/fpdf_parser/include/cpdf_parser.h"

namespace {

const uint8_t defpasscode[32] = {
    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};

void CalcEncryptKey(CPDF_Dictionary* pEncrypt,
                    const uint8_t* password,
                    FX_DWORD pass_size,
                    uint8_t* key,
                    int keylen,
                    FX_BOOL bIgnoreMeta,
                    CPDF_Array* pIdArray) {
  int revision = pEncrypt->GetIntegerBy("R");
  uint8_t passcode[32];
  for (FX_DWORD i = 0; i < 32; i++) {
    passcode[i] = i < pass_size ? password[i] : defpasscode[i - pass_size];
  }
  uint8_t md5[100];
  CRYPT_MD5Start(md5);
  CRYPT_MD5Update(md5, passcode, 32);
  CFX_ByteString okey = pEncrypt->GetStringBy("O");
  CRYPT_MD5Update(md5, (uint8_t*)okey.c_str(), okey.GetLength());
  FX_DWORD perm = pEncrypt->GetIntegerBy("P");
  CRYPT_MD5Update(md5, (uint8_t*)&perm, 4);
  if (pIdArray) {
    CFX_ByteString id = pIdArray->GetStringAt(0);
    CRYPT_MD5Update(md5, (uint8_t*)id.c_str(), id.GetLength());
  }
  if (!bIgnoreMeta && revision >= 3 &&
      !pEncrypt->GetIntegerBy("EncryptMetadata", 1)) {
    FX_DWORD tag = (FX_DWORD)-1;
    CRYPT_MD5Update(md5, (uint8_t*)&tag, 4);
  }
  uint8_t digest[16];
  CRYPT_MD5Finish(md5, digest);
  FX_DWORD copy_len = keylen;
  if (copy_len > sizeof(digest)) {
    copy_len = sizeof(digest);
  }
  if (revision >= 3) {
    for (int i = 0; i < 50; i++) {
      CRYPT_MD5Generate(digest, copy_len, digest);
    }
  }
  FXSYS_memset(key, 0, keylen);
  FXSYS_memcpy(key, digest, copy_len);
}

}  // namespace

IPDF_SecurityHandler::~IPDF_SecurityHandler() {}

CPDF_StandardSecurityHandler::CPDF_StandardSecurityHandler() {
  m_Version = 0;
  m_Revision = 0;
  m_pParser = NULL;
  m_pEncryptDict = NULL;
  m_Permissions = 0;
  m_Cipher = FXCIPHER_NONE;
  m_KeyLen = 0;
}

CPDF_StandardSecurityHandler::~CPDF_StandardSecurityHandler() {}

IPDF_CryptoHandler* CPDF_StandardSecurityHandler::CreateCryptoHandler() {
  return new CPDF_StandardCryptoHandler;
}

FX_BOOL CPDF_StandardSecurityHandler::OnInit(CPDF_Parser* pParser,
                                             CPDF_Dictionary* pEncryptDict) {
  m_pParser = pParser;
  if (!LoadDict(pEncryptDict)) {
    return FALSE;
  }
  if (m_Cipher == FXCIPHER_NONE) {
    return TRUE;
  }
  return CheckSecurity(m_KeyLen);
}
FX_BOOL CPDF_StandardSecurityHandler::CheckSecurity(int32_t key_len) {
  CFX_ByteString password = m_pParser->GetPassword();
  if (CheckPassword(password, password.GetLength(), TRUE, m_EncryptKey,
                    key_len)) {
    if (password.IsEmpty()) {
      if (!CheckPassword(password, password.GetLength(), FALSE, m_EncryptKey,
                         key_len)) {
        return FALSE;
      }
    }
    return TRUE;
  }
  return CheckPassword(password, password.GetLength(), FALSE, m_EncryptKey,
                       key_len);
}
FX_DWORD CPDF_StandardSecurityHandler::GetPermissions() {
  return m_Permissions;
}
static FX_BOOL _LoadCryptInfo(CPDF_Dictionary* pEncryptDict,
                              const CFX_ByteStringC& name,
                              int& cipher,
                              int& keylen) {
  int Version = pEncryptDict->GetIntegerBy("V");
  cipher = FXCIPHER_RC4;
  keylen = 0;
  if (Version >= 4) {
    CPDF_Dictionary* pCryptFilters = pEncryptDict->GetDictBy("CF");
    if (!pCryptFilters) {
      return FALSE;
    }
    if (name == "Identity") {
      cipher = FXCIPHER_NONE;
    } else {
      CPDF_Dictionary* pDefFilter = pCryptFilters->GetDictBy(name);
      if (!pDefFilter) {
        return FALSE;
      }
      int nKeyBits = 0;
      if (Version == 4) {
        nKeyBits = pDefFilter->GetIntegerBy("Length", 0);
        if (nKeyBits == 0) {
          nKeyBits = pEncryptDict->GetIntegerBy("Length", 128);
        }
      } else {
        nKeyBits = pEncryptDict->GetIntegerBy("Length", 256);
      }
      if (nKeyBits < 40) {
        nKeyBits *= 8;
      }
      keylen = nKeyBits / 8;
      CFX_ByteString cipher_name = pDefFilter->GetStringBy("CFM");
      if (cipher_name == "AESV2" || cipher_name == "AESV3") {
        cipher = FXCIPHER_AES;
      }
    }
  } else {
    keylen = Version > 1 ? pEncryptDict->GetIntegerBy("Length", 40) / 8 : 5;
  }
  if (keylen > 32 || keylen < 0) {
    return FALSE;
  }
  return TRUE;
}

FX_BOOL CPDF_StandardSecurityHandler::LoadDict(CPDF_Dictionary* pEncryptDict) {
  m_pEncryptDict = pEncryptDict;
  m_Version = pEncryptDict->GetIntegerBy("V");
  m_Revision = pEncryptDict->GetIntegerBy("R");
  m_Permissions = pEncryptDict->GetIntegerBy("P", -1);
  if (m_Version < 4) {
    return _LoadCryptInfo(pEncryptDict, CFX_ByteString(), m_Cipher, m_KeyLen);
  }
  CFX_ByteString stmf_name = pEncryptDict->GetStringBy("StmF");
  CFX_ByteString strf_name = pEncryptDict->GetStringBy("StrF");
  if (stmf_name != strf_name) {
    return FALSE;
  }
  if (!_LoadCryptInfo(pEncryptDict, strf_name, m_Cipher, m_KeyLen)) {
    return FALSE;
  }
  return TRUE;
}

FX_BOOL CPDF_StandardSecurityHandler::LoadDict(CPDF_Dictionary* pEncryptDict,
                                               FX_DWORD type,
                                               int& cipher,
                                               int& key_len) {
  m_pEncryptDict = pEncryptDict;
  m_Version = pEncryptDict->GetIntegerBy("V");
  m_Revision = pEncryptDict->GetIntegerBy("R");
  m_Permissions = pEncryptDict->GetIntegerBy("P", -1);
  CFX_ByteString strf_name, stmf_name;
  if (m_Version >= 4) {
    stmf_name = pEncryptDict->GetStringBy("StmF");
    strf_name = pEncryptDict->GetStringBy("StrF");
    if (stmf_name != strf_name) {
      return FALSE;
    }
  }
  if (!_LoadCryptInfo(pEncryptDict, strf_name, cipher, key_len)) {
    return FALSE;
  }
  m_Cipher = cipher;
  m_KeyLen = key_len;
  return TRUE;
}

FX_BOOL CPDF_StandardSecurityHandler::GetCryptInfo(int& cipher,
                                                   const uint8_t*& buffer,
                                                   int& keylen) {
  cipher = m_Cipher;
  buffer = m_EncryptKey;
  keylen = m_KeyLen;
  return TRUE;
}
#define FX_GET_32WORD(n, b, i)                                        \
  {                                                                   \
    (n) = (FX_DWORD)(                                                 \
        ((uint64_t)(b)[(i)] << 24) | ((uint64_t)(b)[(i) + 1] << 16) | \
        ((uint64_t)(b)[(i) + 2] << 8) | ((uint64_t)(b)[(i) + 3]));    \
  }
int BigOrder64BitsMod3(uint8_t* data) {
  uint64_t ret = 0;
  for (int i = 0; i < 4; ++i) {
    FX_DWORD value;
    FX_GET_32WORD(value, data, 4 * i);
    ret <<= 32;
    ret |= value;
    ret %= 3;
  }
  return (int)ret;
}
void Revision6_Hash(const uint8_t* password,
                    FX_DWORD size,
                    const uint8_t* salt,
                    const uint8_t* vector,
                    uint8_t* hash) {
  int iBlockSize = 32;
  uint8_t sha[128];
  CRYPT_SHA256Start(sha);
  CRYPT_SHA256Update(sha, password, size);
  CRYPT_SHA256Update(sha, salt, 8);
  if (vector) {
    CRYPT_SHA256Update(sha, vector, 48);
  }
  uint8_t digest[32];
  CRYPT_SHA256Finish(sha, digest);
  CFX_ByteTextBuf buf;
  uint8_t* input = digest;
  uint8_t* key = input;
  uint8_t* iv = input + 16;
  uint8_t* E = buf.GetBuffer();
  int iBufLen = buf.GetLength();
  CFX_ByteTextBuf interDigest;
  int i = 0;
  uint8_t* aes = FX_Alloc(uint8_t, 2048);
  while (i < 64 || i < E[iBufLen - 1] + 32) {
    int iRoundSize = size + iBlockSize;
    if (vector) {
      iRoundSize += 48;
    }
    iBufLen = iRoundSize * 64;
    buf.EstimateSize(iBufLen);
    E = buf.GetBuffer();
    CFX_ByteTextBuf content;
    for (int j = 0; j < 64; ++j) {
      content.AppendBlock(password, size);
      content.AppendBlock(input, iBlockSize);
      if (vector) {
        content.AppendBlock(vector, 48);
      }
    }
    CRYPT_AESSetKey(aes, 16, key, 16, TRUE);
    CRYPT_AESSetIV(aes, iv);
    CRYPT_AESEncrypt(aes, E, content.GetBuffer(), iBufLen);
    int iHash = 0;
    switch (BigOrder64BitsMod3(E)) {
      case 0:
        iHash = 0;
        iBlockSize = 32;
        break;
      case 1:
        iHash = 1;
        iBlockSize = 48;
        break;
      default:
        iHash = 2;
        iBlockSize = 64;
        break;
    }
    interDigest.EstimateSize(iBlockSize);
    input = interDigest.GetBuffer();
    if (iHash == 0) {
      CRYPT_SHA256Generate(E, iBufLen, input);
    } else if (iHash == 1) {
      CRYPT_SHA384Generate(E, iBufLen, input);
    } else if (iHash == 2) {
      CRYPT_SHA512Generate(E, iBufLen, input);
    }
    key = input;
    iv = input + 16;
    ++i;
  }
  FX_Free(aes);
  if (hash) {
    FXSYS_memcpy(hash, input, 32);
  }
}
FX_BOOL CPDF_StandardSecurityHandler::AES256_CheckPassword(
    const uint8_t* password,
    FX_DWORD size,
    FX_BOOL bOwner,
    uint8_t* key) {
  CFX_ByteString okey =
      m_pEncryptDict ? m_pEncryptDict->GetStringBy("O") : CFX_ByteString();
  if (okey.GetLength() < 48) {
    return FALSE;
  }
  CFX_ByteString ukey =
      m_pEncryptDict ? m_pEncryptDict->GetStringBy("U") : CFX_ByteString();
  if (ukey.GetLength() < 48) {
    return FALSE;
  }
  const uint8_t* pkey = bOwner ? (const uint8_t*)okey : (const uint8_t*)ukey;
  uint8_t sha[128];
  uint8_t digest[32];
  if (m_Revision >= 6) {
    Revision6_Hash(password, size, (const uint8_t*)pkey + 32,
                   (bOwner ? (const uint8_t*)ukey : NULL), digest);
  } else {
    CRYPT_SHA256Start(sha);
    CRYPT_SHA256Update(sha, password, size);
    CRYPT_SHA256Update(sha, pkey + 32, 8);
    if (bOwner) {
      CRYPT_SHA256Update(sha, ukey, 48);
    }
    CRYPT_SHA256Finish(sha, digest);
  }
  if (FXSYS_memcmp(digest, pkey, 32) != 0) {
    return FALSE;
  }
  if (!key) {
    return TRUE;
  }
  if (m_Revision >= 6) {
    Revision6_Hash(password, size, (const uint8_t*)pkey + 40,
                   (bOwner ? (const uint8_t*)ukey : NULL), digest);
  } else {
    CRYPT_SHA256Start(sha);
    CRYPT_SHA256Update(sha, password, size);
    CRYPT_SHA256Update(sha, pkey + 40, 8);
    if (bOwner) {
      CRYPT_SHA256Update(sha, ukey, 48);
    }
    CRYPT_SHA256Finish(sha, digest);
  }
  CFX_ByteString ekey = m_pEncryptDict
                            ? m_pEncryptDict->GetStringBy(bOwner ? "OE" : "UE")
                            : CFX_ByteString();
  if (ekey.GetLength() < 32) {
    return FALSE;
  }
  uint8_t* aes = FX_Alloc(uint8_t, 2048);
  CRYPT_AESSetKey(aes, 16, digest, 32, FALSE);
  uint8_t iv[16];
  FXSYS_memset(iv, 0, 16);
  CRYPT_AESSetIV(aes, iv);
  CRYPT_AESDecrypt(aes, key, ekey, 32);
  CRYPT_AESSetKey(aes, 16, key, 32, FALSE);
  CRYPT_AESSetIV(aes, iv);
  CFX_ByteString perms = m_pEncryptDict->GetStringBy("Perms");
  if (perms.IsEmpty()) {
    return FALSE;
  }
  uint8_t perms_buf[16];
  FXSYS_memset(perms_buf, 0, sizeof(perms_buf));
  FX_DWORD copy_len = sizeof(perms_buf);
  if (copy_len > (FX_DWORD)perms.GetLength()) {
    copy_len = perms.GetLength();
  }
  FXSYS_memcpy(perms_buf, (const uint8_t*)perms, copy_len);
  uint8_t buf[16];
  CRYPT_AESDecrypt(aes, buf, perms_buf, 16);
  FX_Free(aes);
  if (buf[9] != 'a' || buf[10] != 'd' || buf[11] != 'b') {
    return FALSE;
  }
  if (FXDWORD_GET_LSBFIRST(buf) != m_Permissions) {
    return FALSE;
  }
  if ((buf[8] == 'T' && !IsMetadataEncrypted()) ||
      (buf[8] == 'F' && IsMetadataEncrypted())) {
    return FALSE;
  }
  return TRUE;
}

int CPDF_StandardSecurityHandler::CheckPassword(const uint8_t* password,
                                                FX_DWORD size,
                                                FX_BOOL bOwner,
                                                uint8_t* key,
                                                int32_t key_len) {
  if (m_Revision >= 5) {
    return AES256_CheckPassword(password, size, bOwner, key);
  }
  uint8_t keybuf[32];
  if (!key) {
    key = keybuf;
  }
  if (bOwner) {
    return CheckOwnerPassword(password, size, key, key_len);
  }
  return CheckUserPassword(password, size, FALSE, key, key_len) ||
         CheckUserPassword(password, size, TRUE, key, key_len);
}
FX_BOOL CPDF_StandardSecurityHandler::CheckUserPassword(
    const uint8_t* password,
    FX_DWORD pass_size,
    FX_BOOL bIgnoreEncryptMeta,
    uint8_t* key,
    int32_t key_len) {
  CalcEncryptKey(m_pEncryptDict, password, pass_size, key, key_len,
                 bIgnoreEncryptMeta, m_pParser->GetIDArray());
  CFX_ByteString ukey =
      m_pEncryptDict ? m_pEncryptDict->GetStringBy("U") : CFX_ByteString();
  if (ukey.GetLength() < 16) {
    return FALSE;
  }
  uint8_t ukeybuf[32];
  if (m_Revision == 2) {
    FXSYS_memcpy(ukeybuf, defpasscode, 32);
    CRYPT_ArcFourCryptBlock(ukeybuf, 32, key, key_len);
  } else {
    uint8_t test[32], tmpkey[32];
    FX_DWORD copy_len = sizeof(test);
    if (copy_len > (FX_DWORD)ukey.GetLength()) {
      copy_len = ukey.GetLength();
    }
    FXSYS_memset(test, 0, sizeof(test));
    FXSYS_memset(tmpkey, 0, sizeof(tmpkey));
    FXSYS_memcpy(test, ukey.c_str(), copy_len);
    for (int i = 19; i >= 0; i--) {
      for (int j = 0; j < key_len; j++) {
        tmpkey[j] = key[j] ^ i;
      }
      CRYPT_ArcFourCryptBlock(test, 32, tmpkey, key_len);
    }
    uint8_t md5[100];
    CRYPT_MD5Start(md5);
    CRYPT_MD5Update(md5, defpasscode, 32);
    CPDF_Array* pIdArray = m_pParser->GetIDArray();
    if (pIdArray) {
      CFX_ByteString id = pIdArray->GetStringAt(0);
      CRYPT_MD5Update(md5, (uint8_t*)id.c_str(), id.GetLength());
    }
    CRYPT_MD5Finish(md5, ukeybuf);
    return FXSYS_memcmp(test, ukeybuf, 16) == 0;
  }
  if (FXSYS_memcmp((void*)ukey.c_str(), ukeybuf, 16) == 0) {
    return TRUE;
  }
  return FALSE;
}
CFX_ByteString CPDF_StandardSecurityHandler::GetUserPassword(
    const uint8_t* owner_pass,
    FX_DWORD pass_size,
    int32_t key_len) {
  CFX_ByteString okey = m_pEncryptDict->GetStringBy("O");
  uint8_t passcode[32];
  FX_DWORD i;
  for (i = 0; i < 32; i++) {
    passcode[i] = i < pass_size ? owner_pass[i] : defpasscode[i - pass_size];
  }
  uint8_t digest[16];
  CRYPT_MD5Generate(passcode, 32, digest);
  if (m_Revision >= 3) {
    for (int i = 0; i < 50; i++) {
      CRYPT_MD5Generate(digest, 16, digest);
    }
  }
  uint8_t enckey[32];
  FXSYS_memset(enckey, 0, sizeof(enckey));
  FX_DWORD copy_len = key_len;
  if (copy_len > sizeof(digest)) {
    copy_len = sizeof(digest);
  }
  FXSYS_memcpy(enckey, digest, copy_len);
  int okeylen = okey.GetLength();
  if (okeylen > 32) {
    okeylen = 32;
  }
  uint8_t okeybuf[64];
  FXSYS_memset(okeybuf, 0, sizeof(okeybuf));
  FXSYS_memcpy(okeybuf, okey.c_str(), okeylen);
  if (m_Revision == 2) {
    CRYPT_ArcFourCryptBlock(okeybuf, okeylen, enckey, key_len);
  } else {
    for (int i = 19; i >= 0; i--) {
      uint8_t tempkey[32];
      FXSYS_memset(tempkey, 0, sizeof(tempkey));
      for (int j = 0; j < m_KeyLen; j++) {
        tempkey[j] = enckey[j] ^ i;
      }
      CRYPT_ArcFourCryptBlock(okeybuf, okeylen, tempkey, key_len);
    }
  }
  int len = 32;
  while (len && defpasscode[len - 1] == okeybuf[len - 1]) {
    len--;
  }
  return CFX_ByteString(okeybuf, len);
}
FX_BOOL CPDF_StandardSecurityHandler::CheckOwnerPassword(
    const uint8_t* password,
    FX_DWORD pass_size,
    uint8_t* key,
    int32_t key_len) {
  CFX_ByteString user_pass = GetUserPassword(password, pass_size, key_len);
  if (CheckUserPassword(user_pass, user_pass.GetLength(), FALSE, key,
                        key_len)) {
    return TRUE;
  }
  return CheckUserPassword(user_pass, user_pass.GetLength(), TRUE, key,
                           key_len);
}
FX_BOOL CPDF_StandardSecurityHandler::IsMetadataEncrypted() {
  return m_pEncryptDict->GetBooleanBy("EncryptMetadata", TRUE);
}

void CPDF_StandardSecurityHandler::OnCreate(CPDF_Dictionary* pEncryptDict,
                                            CPDF_Array* pIdArray,
                                            const uint8_t* user_pass,
                                            FX_DWORD user_size,
                                            const uint8_t* owner_pass,
                                            FX_DWORD owner_size,
                                            FX_BOOL bDefault,
                                            FX_DWORD type) {
  int cipher = 0, key_len = 0;
  if (!LoadDict(pEncryptDict, type, cipher, key_len)) {
    return;
  }
  if (bDefault && (!owner_pass || owner_size == 0)) {
    owner_pass = user_pass;
    owner_size = user_size;
  }
  if (m_Revision >= 5) {
    int t = (int)time(NULL);
    uint8_t sha[128];
    CRYPT_SHA256Start(sha);
    CRYPT_SHA256Update(sha, (uint8_t*)&t, sizeof t);
    CRYPT_SHA256Update(sha, m_EncryptKey, 32);
    CRYPT_SHA256Update(sha, (uint8_t*)"there", 5);
    CRYPT_SHA256Finish(sha, m_EncryptKey);
    AES256_SetPassword(pEncryptDict, user_pass, user_size, FALSE, m_EncryptKey);
    if (bDefault) {
      AES256_SetPassword(pEncryptDict, owner_pass, owner_size, TRUE,
                         m_EncryptKey);
      AES256_SetPerms(pEncryptDict, m_Permissions,
                      pEncryptDict->GetBooleanBy("EncryptMetadata", TRUE),
                      m_EncryptKey);
    }
    return;
  }
  if (bDefault) {
    uint8_t passcode[32];
    FX_DWORD i;
    for (i = 0; i < 32; i++) {
      passcode[i] =
          i < owner_size ? owner_pass[i] : defpasscode[i - owner_size];
    }
    uint8_t digest[16];
    CRYPT_MD5Generate(passcode, 32, digest);
    if (m_Revision >= 3) {
      for (int i = 0; i < 50; i++) {
        CRYPT_MD5Generate(digest, 16, digest);
      }
    }
    uint8_t enckey[32];
    FXSYS_memcpy(enckey, digest, key_len);
    for (i = 0; i < 32; i++) {
      passcode[i] = i < user_size ? user_pass[i] : defpasscode[i - user_size];
    }
    CRYPT_ArcFourCryptBlock(passcode, 32, enckey, key_len);
    uint8_t tempkey[32];
    if (m_Revision >= 3) {
      for (i = 1; i <= 19; i++) {
        for (int j = 0; j < key_len; j++) {
          tempkey[j] = enckey[j] ^ (uint8_t)i;
        }
        CRYPT_ArcFourCryptBlock(passcode, 32, tempkey, key_len);
      }
    }
    pEncryptDict->SetAtString("O", CFX_ByteString(passcode, 32));
  }
  CalcEncryptKey(m_pEncryptDict, (uint8_t*)user_pass, user_size, m_EncryptKey,
                 key_len, FALSE, pIdArray);
  if (m_Revision < 3) {
    uint8_t tempbuf[32];
    FXSYS_memcpy(tempbuf, defpasscode, 32);
    CRYPT_ArcFourCryptBlock(tempbuf, 32, m_EncryptKey, key_len);
    pEncryptDict->SetAtString("U", CFX_ByteString(tempbuf, 32));
  } else {
    uint8_t md5[100];
    CRYPT_MD5Start(md5);
    CRYPT_MD5Update(md5, defpasscode, 32);
    if (pIdArray) {
      CFX_ByteString id = pIdArray->GetStringAt(0);
      CRYPT_MD5Update(md5, (uint8_t*)id.c_str(), id.GetLength());
    }
    uint8_t digest[32];
    CRYPT_MD5Finish(md5, digest);
    CRYPT_ArcFourCryptBlock(digest, 16, m_EncryptKey, key_len);
    uint8_t tempkey[32];
    for (int i = 1; i <= 19; i++) {
      for (int j = 0; j < key_len; j++) {
        tempkey[j] = m_EncryptKey[j] ^ (uint8_t)i;
      }
      CRYPT_ArcFourCryptBlock(digest, 16, tempkey, key_len);
    }
    CRYPT_MD5Generate(digest, 16, digest + 16);
    pEncryptDict->SetAtString("U", CFX_ByteString(digest, 32));
  }
}
void CPDF_StandardSecurityHandler::OnCreate(CPDF_Dictionary* pEncryptDict,
                                            CPDF_Array* pIdArray,
                                            const uint8_t* user_pass,
                                            FX_DWORD user_size,
                                            const uint8_t* owner_pass,
                                            FX_DWORD owner_size,
                                            FX_DWORD type) {
  OnCreate(pEncryptDict, pIdArray, user_pass, user_size, owner_pass, owner_size,
           TRUE, type);
}
void CPDF_StandardSecurityHandler::OnCreate(CPDF_Dictionary* pEncryptDict,
                                            CPDF_Array* pIdArray,
                                            const uint8_t* user_pass,
                                            FX_DWORD user_size,
                                            FX_DWORD type) {
  OnCreate(pEncryptDict, pIdArray, user_pass, user_size, NULL, 0, FALSE, type);
}
void CPDF_StandardSecurityHandler::AES256_SetPassword(
    CPDF_Dictionary* pEncryptDict,
    const uint8_t* password,
    FX_DWORD size,
    FX_BOOL bOwner,
    const uint8_t* key) {
  uint8_t sha[128];
  CRYPT_SHA1Start(sha);
  CRYPT_SHA1Update(sha, key, 32);
  CRYPT_SHA1Update(sha, (uint8_t*)"hello", 5);
  uint8_t digest[20];
  CRYPT_SHA1Finish(sha, digest);
  CFX_ByteString ukey = pEncryptDict->GetStringBy("U");
  uint8_t digest1[48];
  if (m_Revision >= 6) {
    Revision6_Hash(password, size, digest,
                   (bOwner ? (const uint8_t*)ukey : NULL), digest1);
  } else {
    CRYPT_SHA256Start(sha);
    CRYPT_SHA256Update(sha, password, size);
    CRYPT_SHA256Update(sha, digest, 8);
    if (bOwner) {
      CRYPT_SHA256Update(sha, ukey, ukey.GetLength());
    }
    CRYPT_SHA256Finish(sha, digest1);
  }
  FXSYS_memcpy(digest1 + 32, digest, 16);
  pEncryptDict->SetAtString(bOwner ? "O" : "U", CFX_ByteString(digest1, 48));
  if (m_Revision >= 6) {
    Revision6_Hash(password, size, digest + 8,
                   (bOwner ? (const uint8_t*)ukey : NULL), digest1);
  } else {
    CRYPT_SHA256Start(sha);
    CRYPT_SHA256Update(sha, password, size);
    CRYPT_SHA256Update(sha, digest + 8, 8);
    if (bOwner) {
      CRYPT_SHA256Update(sha, ukey, ukey.GetLength());
    }
    CRYPT_SHA256Finish(sha, digest1);
  }
  uint8_t* aes = FX_Alloc(uint8_t, 2048);
  CRYPT_AESSetKey(aes, 16, digest1, 32, TRUE);
  uint8_t iv[16];
  FXSYS_memset(iv, 0, 16);
  CRYPT_AESSetIV(aes, iv);
  CRYPT_AESEncrypt(aes, digest1, key, 32);
  FX_Free(aes);
  pEncryptDict->SetAtString(bOwner ? "OE" : "UE", CFX_ByteString(digest1, 32));
}
void CPDF_StandardSecurityHandler::AES256_SetPerms(
    CPDF_Dictionary* pEncryptDict,
    FX_DWORD permissions,
    FX_BOOL bEncryptMetadata,
    const uint8_t* key) {
  uint8_t buf[16];
  buf[0] = (uint8_t)permissions;
  buf[1] = (uint8_t)(permissions >> 8);
  buf[2] = (uint8_t)(permissions >> 16);
  buf[3] = (uint8_t)(permissions >> 24);
  buf[4] = 0xff;
  buf[5] = 0xff;
  buf[6] = 0xff;
  buf[7] = 0xff;
  buf[8] = bEncryptMetadata ? 'T' : 'F';
  buf[9] = 'a';
  buf[10] = 'd';
  buf[11] = 'b';
  uint8_t* aes = FX_Alloc(uint8_t, 2048);
  CRYPT_AESSetKey(aes, 16, key, 32, TRUE);
  uint8_t iv[16], buf1[16];
  FXSYS_memset(iv, 0, 16);
  CRYPT_AESSetIV(aes, iv);
  CRYPT_AESEncrypt(aes, buf1, buf, 16);
  FX_Free(aes);
  pEncryptDict->SetAtString("Perms", CFX_ByteString(buf1, 16));
}