VeraCrypt
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<h1>Unencrypted Data in RAM</h1>
<div style="text-align:left; margin-top:19px; margin-bottom:19px; padding-top:0px; padding-bottom:0px">
It is important to note that VeraCrypt is <em style="text-align:left">disk</em> encryption software, which encrypts only disks, not RAM (memory).</div>
<div style="text-align:left; margin-top:19px; margin-bottom:19px; padding-top:0px; padding-bottom:0px">
Keep in mind that most programs do not clear the memory area (buffers) in which they store unencrypted (portions of) files they load from a VeraCrypt volume. This means that after you exit such a program, unencrypted data it worked with may remain in memory
 (RAM) until the computer is turned off (and, according to some researchers, even for some time after the power is turned off*). Also note that if you open a file stored on a VeraCrypt volume, for example, in a text editor and then force dismount on the VeraCrypt
 volume, then the file will remain unencrypted in the area of memory (RAM) used by (allocated to) the text editor. This also applies to forced auto-dismount.</div>
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Inherently, unencrypted master keys have to be stored in RAM too. When a non-system VeraCrypt volume is dismounted, VeraCrypt erases its master keys (stored in RAM). When the computer is cleanly restarted (or cleanly shut down), all non-system VeraCrypt volumes
 are automatically dismounted and, thus, all master keys stored in RAM are erased by the VeraCrypt driver (except master keys for system partitions/drives &mdash; see below). However, when power supply is abruptly interrupted, when the computer is reset (not
 cleanly restarted), or when the system crashes, <strong style="text-align:left">
VeraCrypt naturally stops running and therefore cannot </strong>erase any keys or any other sensitive data. Furthermore, as Microsoft does not provide any appropriate API for handling hibernation and shutdown, master keys used for system encryption cannot be
 reliably (and are not) erased from RAM when the computer hibernates, is shut down or restarted.**</div>
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Starting from version 1.24, VeraCrypt introduces a mechanism to encrypt master keys and cached passwords in RAM. This RAM encryption mechanism must be activated manually in "Performance/Driver Configuration" dialog. RAM encryption comes with a performance overhead (between 5% and 15% depending on the CPU speed) and it disables Windows hibernate. <br>
Moreover, VeraCrypt 1.24 and above provide an additional security mechanism when system encryption is used that makes VeraCrypt erase master keys from RAM when a new device is connected to the PC. This additional mechanism can be activated using an option in System Settings dialog.<br/>
Even though both above mechanisms provides strong protection for masterskeys and cached password, users should still take usual precautions related for the safery of sensitive data in RAM.</div>
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To summarize, VeraCrypt <strong style="text-align:left">cannot</strong> and does <strong style="text-align:left">
not</strong> ensure that RAM contains no sensitive data (e.g. passwords, master keys, or decrypted data). Therefore, after each session in which you work with a VeraCrypt volume or in which an encrypted operating system is running, you must shut down (or, if
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hibernation file</a> is <a href="System%20Encryption.html" style="text-align:left; color:#0080c0; text-decoration:none.html">
encrypted</a>, hibernate) the computer and then leave it powered off for at least several minutes (the longer, the better) before turning it on again. This is required to clear the RAM (also see the section
<a href="Hibernation%20File.html" style="text-align:left; color:#0080c0; text-decoration:none.html">
Hibernation File</a>).</td>
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<p><span style="text-align:left; font-size:10px; line-height:12px">* Allegedly, for 1.5-35 seconds under normal operating temperatures (26-44 &deg;C) and up to several hours when the memory modules are cooled (when the computer is running) to very low temperatures
 (e.g. -50&nbsp;&deg;C). New types of memory modules allegedly exhibit a much shorter decay time (e.g. 1.5-2.5 seconds) than older types (as of 2008).</span><br style="text-align:left">
<span style="text-align:left; font-size:10px; line-height:12px">** Before a key can be erased from RAM, the corresponding VeraCrypt volume must be dismounted. For non-system volumes, this does not cause any problems. However, as Microsoft currently does not
 provide any appropriate API for handling the final phase of the system shutdown process, paging files located on encrypted system volumes that are dismounted during the system shutdown process may still contain valid swapped-out memory pages (including portions
 of Windows system files). This could cause 'blue screen' errors. Therefore, to prevent 'blue screen' errors, VeraCrypt does not dismount encrypted system volumes and consequently cannot clear the master keys of the system volumes when the system is shut down
 or restarted.</span></p>
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ELLIA_KS # endif #else #ifdef TC_WINDOWS_BOOT #define MAX_EXPANDED_KEY VC_MAX((AES_KS + SERPENT_KS + TWOFISH_KS), CAMELLIA_KS) #else #define MAX_EXPANDED_KEY VC_MAX(VC_MAX(VC_MAX(VC_MAX((AES_KS + SERPENT_KS + TWOFISH_KS), GOST_KS), CAMELLIA_KS + KUZNYECHIK_KS + SERPENT_KS), KUZNYECHIK_KS + TWOFISH_KS), AES_KS + KUZNYECHIK_KS) #endif #endif #ifdef DEBUG # define PRAND_DISK_WIPE_PASSES 3 #else # define PRAND_DISK_WIPE_PASSES 256 #endif /* specific value for volume header wipe used only when drive is fully wiped. */ #define PRAND_HEADER_WIPE_PASSES 3 #if !defined (TC_WINDOWS_BOOT) || defined (TC_WINDOWS_BOOT_AES) # include "Aes.h" #else # include "AesSmall.h" #endif #include "Aes_hw_cpu.h" #if !defined (TC_WINDOWS_BOOT) && !defined (_UEFI) # include "SerpentFast.h" #else # include "Serpent.h" #endif #include "Twofish.h" #include "Rmd160.h" #ifndef TC_WINDOWS_BOOT # include "Sha2.h" # include "Whirlpool.h" # include "Streebog.h" # include "GostCipher.h" # include "kuznyechik.h" # include "Camellia.h" #else # include "CamelliaSmall.h" #endif #include "GfMul.h" #include "Password.h" #ifndef TC_WINDOWS_BOOT #include "config.h" typedef struct keyInfo_t { int noIterations; /* Number of times to iterate (PKCS-5) */ int keyLength; /* Length of the key */ uint64 dummy; /* Dummy field to ensure 16-byte alignment of this structure */ __int8 salt[PKCS5_SALT_SIZE]; /* PKCS-5 salt */ CRYPTOPP_ALIGN_DATA(16) __int8 master_keydata[MASTER_KEYDATA_SIZE]; /* Concatenated master primary and secondary key(s) (XTS mode). For LRW (deprecated/legacy), it contains the tweak key before the master key(s). For CBC (deprecated/legacy), it contains the IV seed before the master key(s). */ CRYPTOPP_ALIGN_DATA(16) __int8 userKey[MAX_PASSWORD]; /* Password (to which keyfiles may have been applied). WITHOUT +1 for the null terminator. */ } KEY_INFO, *PKEY_INFO; #endif typedef struct CRYPTO_INFO_t { int ea; /* Encryption algorithm ID */ int mode; /* Mode of operation (e.g., XTS) */ int pkcs5; /* PRF algorithm */ unsigned __int8 ks[MAX_EXPANDED_KEY]; /* Primary key schedule (if it is a cascade, it conatins multiple concatenated keys) */ unsigned __int8 ks2[MAX_EXPANDED_KEY]; /* Secondary key schedule (if cascade, multiple concatenated) for XTS mode. */ BOOL hiddenVolume; // Indicates whether the volume is mounted/mountable as hidden volume #ifndef TC_WINDOWS_BOOT uint16 HeaderVersion; #ifdef TC_WINDOWS_DRIVER unsigned __int8 master_keydata_hash[RIPEMD160_DIGESTSIZE]; #else CRYPTOPP_ALIGN_DATA(16) unsigned __int8 master_keydata[MASTER_KEYDATA_SIZE]; /* This holds the volume header area containing concatenated master key(s) and secondary key(s) (XTS mode). For LRW (deprecated/legacy), it contains the tweak key before the master key(s). For CBC (deprecated/legacy), it contains the IV seed before the master key(s). */ CRYPTOPP_ALIGN_DATA(16) unsigned __int8 k2[MASTER_KEYDATA_SIZE]; /* For XTS, this contains the secondary key (if cascade, multiple concatenated). For LRW (deprecated/legacy), it contains the tweak key. For CBC (deprecated/legacy), it contains the IV seed. */ #endif int noIterations; BOOL bTrueCryptMode; int volumePim; BOOL bProtectHiddenVolume; // Indicates whether the volume contains a hidden volume to be protected against overwriting BOOL bHiddenVolProtectionAction; // TRUE if a write operation has been denied by the driver in order to prevent the hidden volume from being overwritten (set to FALSE upon volume mount). uint64 volDataAreaOffset; // Absolute position, in bytes, of the first data sector of the volume. uint64 hiddenVolumeSize; // Size of the hidden volume excluding the header (in bytes). Set to 0 for standard volumes. uint64 hiddenVolumeOffset; // Absolute position, in bytes, of the first hidden volume data sector within the host volume (provided that there is a hidden volume within). This must be set for all hidden volumes; in case of a normal volume, this variable is only used when protecting a hidden volume within it. uint64 hiddenVolumeProtectedSize; BOOL bPartitionInInactiveSysEncScope; // If TRUE, the volume is a partition located on an encrypted system drive and mounted without pre-boot authentication. UINT64_STRUCT FirstDataUnitNo; // First data unit number of the volume. This is 0 for file-hosted and non-system partition-hosted volumes. For partitions within key scope of system encryption this reflects real physical offset within the device (this is used e.g. when such a partition is mounted as a regular volume without pre-boot authentication). uint16 RequiredProgramVersion; BOOL LegacyVolume; uint32 SectorSize; #endif // !TC_WINDOWS_BOOT UINT64_STRUCT VolumeSize; UINT64_STRUCT EncryptedAreaStart; UINT64_STRUCT EncryptedAreaLength; uint32 HeaderFlags; } CRYPTO_INFO, *PCRYPTO_INFO; #if defined(_WIN32) || defined(_UEFI) #pragma pack (push) #pragma pack(1) typedef struct BOOT_CRYPTO_HEADER_t { __int16 ea; /* Encryption algorithm ID */ __int16 mode; /* Mode of operation (e.g., XTS) */ __int16 pkcs5; /* PRF algorithm */ } BOOT_CRYPTO_HEADER, *PBOOT_CRYPTO_HEADER; #pragma pack (pop) #endif PCRYPTO_INFO crypto_open (void); #ifndef TC_WINDOWS_BOOT void crypto_loadkey (PKEY_INFO keyInfo, char *lpszUserKey, int nUserKeyLen); void crypto_eraseKeys (PCRYPTO_INFO cryptoInfo); #endif void crypto_close (PCRYPTO_INFO cryptoInfo); int CipherGetBlockSize (int cipher); int CipherGetKeySize (int cipher); int CipherGetKeyScheduleSize (int cipher); BOOL CipherSupportsIntraDataUnitParallelization (int cipher); #ifndef TC_WINDOWS_BOOT const wchar_t * CipherGetName (int cipher); #endif int CipherInit (int cipher, unsigned char *key, unsigned char *ks); #ifndef TC_WINDOWS_BOOT_SINGLE_CIPHER_MODE int EAInit (int ea, unsigned char *key, unsigned char *ks); #else int EAInit (unsigned char *key, unsigned char *ks); #endif BOOL EAInitMode (PCRYPTO_INFO ci, unsigned char* key2); void EncipherBlock(int cipher, void *data, void *ks); void DecipherBlock(int cipher, void *data, void *ks); #ifndef TC_WINDOWS_BOOT void EncipherBlocks (int cipher, void *dataPtr, void *ks, size_t blockCount); void DecipherBlocks (int cipher, void *dataPtr, void *ks, size_t blockCount); #endif int EAGetFirst (); int EAGetCount (void); int EAGetNext (int previousEA); #ifndef TC_WINDOWS_BOOT wchar_t * EAGetName (wchar_t *buf, int ea, int guiDisplay); int EAGetByName (wchar_t *name); #endif int EAGetKeySize (int ea); int EAGetFirstMode (int ea); int EAGetNextMode (int ea, int previousModeId); #ifndef TC_WINDOWS_BOOT wchar_t * EAGetModeName (int ea, int mode, BOOL capitalLetters); #endif int EAGetKeyScheduleSize (int ea); int EAGetLargestKey (); int EAGetLargestKeyForMode (int mode); int EAGetCipherCount (int ea); int EAGetFirstCipher (int ea); int EAGetLastCipher (int ea); int EAGetNextCipher (int ea, int previousCipherId); int EAGetPreviousCipher (int ea, int previousCipherId); #ifndef TC_WINDOWS_BOOT int EAIsFormatEnabled (int ea); int EAIsMbrSysEncEnabled (int ea); #endif BOOL EAIsModeSupported (int ea, int testedMode); #ifndef TC_WINDOWS_BOOT const wchar_t *HashGetName (int hash_algo_id); #ifdef _WIN32 int HashGetIdByName (wchar_t *name); #endif Hash *HashGet (int id); void HashGetName2 (wchar_t *buf, int hashId); BOOL HashIsDeprecated (int hashId); BOOL HashForSystemEncryption (int hashId); int GetMaxPkcs5OutSize (void); #endif void EncryptDataUnits (unsigned __int8 *buf, const UINT64_STRUCT *structUnitNo, uint32 nbrUnits, PCRYPTO_INFO ci); void EncryptDataUnitsCurrentThread (unsigned __int8 *buf, const UINT64_STRUCT *structUnitNo, TC_LARGEST_COMPILER_UINT nbrUnits, PCRYPTO_INFO ci); void DecryptDataUnits (unsigned __int8 *buf, const UINT64_STRUCT *structUnitNo, uint32 nbrUnits, PCRYPTO_INFO ci); void DecryptDataUnitsCurrentThread (unsigned __int8 *buf, const UINT64_STRUCT *structUnitNo, TC_LARGEST_COMPILER_UINT nbrUnits, PCRYPTO_INFO ci); void EncryptBuffer (unsigned __int8 *buf, TC_LARGEST_COMPILER_UINT len, PCRYPTO_INFO cryptoInfo); void DecryptBuffer (unsigned __int8 *buf, TC_LARGEST_COMPILER_UINT len, PCRYPTO_INFO cryptoInfo); BOOL IsAesHwCpuSupported (); void EnableHwEncryption (BOOL enable); BOOL IsHwEncryptionEnabled (); BOOL IsCpuRngSupported (); void EnableCpuRng (BOOL enable); BOOL IsCpuRngEnabled (); #ifdef __cplusplus } #endif #endif /* CRYPTO_H */