clscryptoapi.cls

使用VB写的加密算法库

VERSION 1.0 CLASS
BEGIN
  MultiUse = -1  'True
  Persistable = 0  'NotPersistable
  DataBindingBehavior = 0  'vbNone
  DataSourceBehavior  = 0  'vbNone
  MTSTransactionMode  = 0  'NotAnMTSObject
END
Attribute VB_Name = "clsCryptoAPI"
Attribute VB_GlobalNameSpace = False
Attribute VB_Creatable = True
Attribute VB_PredeclaredId = False
Attribute VB_Exposed = True
Attribute VB_Ext_KEY = "SavedWithClassBuilder6" ,"Yes"
Attribute VB_Ext_KEY = "Top_Level" ,"Yes"
Option Explicit

' ***************************************************************************
' Module:        clsCryptoAPI.cls
'
' Description:   This module is used to make calls to the the advapi32.dll
'                where the functions for CryptoAPI reside.
'
'                Always give credit where credit is due.  If you attach your
'                creditials to a piece of code, you should be available to
'                answer questions concerning that code.
'
' Thanks to:     Phil Fresle http://www.frez.co.uk
'                            Found a lot of good code snippets at his site.
'                            Some you will recognize in this module.
'                Kevin Matthew Goss
'                            His hashing routine pointed me in the right
'                            direction.
'                Alex Rohr   [e-mail]
'                            Collected ideas from his file encryption class.
' ===========================================================================
'    DATE      NAME / eMAIL
'              DESCRIPTION
' -----------  --------------------------------------------------------------
' 29-DEC-2000  Kenneth Ives  [e-mail]
'              Original module
' 10-JUL-2001  Kenneth Ives  [e-mail]
'              Converted to a DLL
' 09-SEP-2001  Kenneth Ives  [e-mail]
'              Enhanced and fixed some minor bugs
' ***************************************************************************

' ---------------------------------------------------------------------------
' Module level variables
' ---------------------------------------------------------------------------
  Private m_blnEnhancedProvider   As Boolean
  Private m_blnBlockCipher        As Boolean
  Private m_blnUseDefaultPWD      As Boolean
  Private m_lngCryptContext       As Long
  Private m_strInputData          As String
  Private m_abytOutputData()      As Byte
  Private m_abytPWord()           As Byte
  
  ' Export keys
  Private Const SIMPLEBLOB        As Long = 1
  Private Const PUBLICKEYBLOB     As Long = 6
  Private Const PRIVATEKEYBLOB    As Long = 7
  Private Const PLAINTEXTKEYBLOB  As Long = 8

  ' Algorithm classes
  Private Const ALG_CLASS_ANY           As Long = 0
  Private Const ALG_CLASS_SIGNATURE     As Long = 8192
  Private Const ALG_CLASS_MSG_ENCRYPT   As Long = 16384
  Private Const ALG_CLASS_DATA_ENCRYPT  As Long = 24576
  Private Const ALG_CLASS_HASH          As Long = 32768

  ' Algorithm types
  Private Const ALG_TYPE_ANY      As Long = 0
  Private Const ALG_TYPE_BLOCK    As Long = 1536
  Private Const ALG_TYPE_STREAM   As Long = 2048

  ' Block cipher IDs
  Private Const ALG_SID_DES       As Long = 1
  Private Const ALG_SID_RC2       As Long = 2
  Private Const ALG_SID_3DES      As Long = 3
  Private Const ALG_SID_3DES_112  As Long = 9

  ' Stream cipher IDs
  Private Const ALG_SID_RC4       As Long = 1

  ' Hash IDs
  Private Const ALG_SID_MD2       As Long = 1
  Private Const ALG_SID_MD4       As Long = 2
  Private Const ALG_SID_MD5       As Long = 3
  Private Const ALG_SID_SHA       As Long = 4
  Private Const ALG_SID_SHA1      As Long = 4
  Private Const HP_HASHVAL        As Long = 2
  
  ' Hash algorithms
  Private Const CALG_MD2          As Long = ALG_CLASS_HASH Or ALG_TYPE_ANY Or ALG_SID_MD2
  Private Const CALG_MD4          As Long = ALG_CLASS_HASH Or ALG_TYPE_ANY Or ALG_SID_MD4
  Private Const CALG_MD5          As Long = ALG_CLASS_HASH Or ALG_TYPE_ANY Or ALG_SID_MD5
  Private Const CALG_SHA          As Long = ALG_CLASS_HASH Or ALG_TYPE_ANY Or ALG_SID_SHA
  Private Const CALG_SHA1         As Long = ALG_CLASS_HASH Or ALG_TYPE_ANY Or ALG_SID_SHA1
  
  ' Block ciphers
  Private Const CALG_RC2          As Long = ALG_CLASS_DATA_ENCRYPT Or ALG_TYPE_BLOCK Or ALG_SID_RC2
  Private Const CALG_DES          As Long = ALG_CLASS_DATA_ENCRYPT Or ALG_TYPE_BLOCK Or ALG_SID_DES
  Private Const CALG_3DES         As Long = ALG_CLASS_DATA_ENCRYPT Or ALG_TYPE_BLOCK Or ALG_SID_3DES
  Private Const CALG_3DES_112     As Long = ALG_CLASS_DATA_ENCRYPT Or ALG_TYPE_BLOCK Or ALG_SID_3DES_112
  
  ' Stream cipher
  Private Const CALG_RC4          As Long = ALG_CLASS_DATA_ENCRYPT Or ALG_TYPE_STREAM Or ALG_SID_RC4

  ' CryptSetProvParam
  Private Const PROV_RSA_FULL        As Long = 1

  ' used when aquiring the provider
  Private Const CRYPT_VERIFYCONTEXT  As Long = &HF0000000
  Private Const CRYPT_NEWKEYSET      As Long = &H8&

  ' Microsoft provider data
  Private Const MS_DEFAULT_PROVIDER  As String = _
                "Microsoft Base Cryptographic Provider v1.0"
                              
  Private Const MS_ENHANCED_PROVIDER As String = _
                "Microsoft Enhanced Cryptographic Provider v1.0"
  
' ---------------------------------------------------------------------------
' Error codes
' ---------------------------------------------------------------------------
  Private Const ERR_CONTEXTOPEN          As Long = 100
  Private Const ERR_LOCKED               As Long = 101
  Private Const ERR_NOCONTEXT            As Long = 102
  Private Const ERR_KEYNOTVALID          As Long = 103

' ---------------------------------------------------------------------------
' Numbers defined by GetLastError
' ---------------------------------------------------------------------------
  Private Const ERROR_BUSY               As Long = 170
  Private Const ERROR_INVALID_PARAMETER  As Long = 87
  Private Const ERROR_NOT_ENOUGH_MEMORY  As Long = 8
  Private Const ERROR_MORE_DATA          As Long = 234
  Private Const NTE_BAD_DATA             As Long = &H80090005

' ---------------------------------------------------------------------------
' Error messages
' ---------------------------------------------------------------------------
  Private Const ERROR_AQUIRING_CONTEXT    As String = "Could not acquire context"
  Private Const ERROR_CREATING_HASH       As String = "Could not create hash"
  Private Const ERROR_CREATING_HASH_DATA  As String = "Could not create hash data"
  Private Const ERROR_DERIVING_KEY        As String = "Could not derive key"
  Private Const ERROR_ENCRYPTING_DATA     As String = "Could not encrypt data"
  Private Const ERROR_DECRYPTING_DATA     As String = "Could not decrypt data"
  Private Const ERROR_INVALID_HEX_STRING  As String = "Not a valid hex string"
  Private Const ERROR_MISSING_PARAMETER   As String = "Both a string and a key are required"
  Private Const ERROR_BAD_ENCRYPTION_TYPE As String = "Invalid encryption type specified"

' ---------------------------------------------------------------------------
' Declares
' ---------------------------------------------------------------------------
  ' CopyMemory moves the contents of a portion of memory from one location
  ' to another. The two locations are identified by pointers to the memory
  ' addresses. After the copy, the original contents in the source are set
  ' to zeros.
  '
  ' Useful whenever you want to move a block of bytes between two memory
  ' locations.  When the source or the destination is an array of numbers
  ' (or of UDTs that contains only numeric and fixed-length strings), you
  ' must pass the first element of the array by reference.  Example below
  ' depicts zero based arrays.
  '
  ' Copy the first 1000 elements of array a() to b().  Both arrays must be
  ' of the same type, and cannot be objects or variable-length strings.
  '
  '    CopyMemory b(0), a(0), 1000 * Len(a(0))
  '
  Private Declare Sub CopyMemory Lib "kernel32" Alias "RtlMoveMemory" _
          (dest As Any, source As Any, ByVal bytes As Long)

  ' The GetTickCount() API will capture the time in milliseconds.  The
  ' counter overflows after 1192.8 hours (49.7 days) from the last reboot.
  Private Declare Function GetTickCount Lib "kernel32" () As Long

  ' The GetLastError function returns the calling thread's last-error
  ' code value.  Most Win32 functions set their calling thread's
  ' last-error value when they fail; a few functions set it when they
  ' succeed.  You should call the GetLastError function immediately when
  ' a function's return value indicates that such a call will return
  ' useful data. That is because some functions call SetLastError(0) when
  ' they succeed, wiping out the error code set by the most recently
  ' failed function.
  Private Declare Function GetLastError Lib "kernel32" () As Long

  ' The CryptHashData function adds data to a specified hash object.
  ' This function and CryptHashSessionKey can be called multiple
  ' times to compute the hash of long or discontinuous data streams.
  Private Declare Function CryptHashData Lib "advapi32.dll" _
          (ByVal hhash As Long, ByVal pbData As String, _
          ByVal dwDataLen As Long, ByVal dwFlags As Long) As Long

  ' Alias of CryptHashData
  Private Declare Function CryptHashDataString Lib "advapi32.dll" _
          Alias "CryptHashData" (ByVal hhash As Long, _
          ByVal bData As String, ByVal dwDataLen As Long, _
          ByVal dwFlags As Long) As Long

  ' Alias of CryptHashData
  Private Declare Function CryptHashDataBytes Lib "advapi32.dll" _
          Alias "CryptHashData" (ByVal hhash As Long, _
          bData As Byte, ByVal dwDataLen As Long, _
          ByVal dwFlags As Long) As Long

  ' The CryptCreateHash function initiates the hashing of a stream of
  ' data. It creates and returns to the calling application a handle
  ' to a CSP hash object. This handle is used in subsequent calls to
  ' CryptHashData and CryptHashSessionKey to hash session keys and
  ' other streams of data.
  Private Declare Function CryptCreateHash Lib "advapi32.dll" _
          (ByVal hProv As Long, ByVal algid As Long, _
          ByVal hkey As Long, ByVal dwFlags As Long, _
          ByRef phHash As Long) As Long

  ' The CryptSignHash function signs data. Because all signature
  ' algorithms are asymmetric and thus slow, the CryptoAPI does not
  ' allow data be signed directly. Instead, data is first hashed and
  ' CryptSignHash is used to sign the hash.
  Private Declare Function CryptSignHash Lib "advapi32.dll" _
          Alias "CryptSignHashA" (ByVal hhash As Long, _
          ByVal hkey As Long, ByVal Description As Long, _
          ByVal dwFlags As Long, ByVal pData As Long, _
          dwDataLength As Long) As Long

  ' The CryptVerifySignature function verifies the signature of a
  ' hash object.  Before calling this function, CryptCreateHash must be
  ' called to create the handle of a hash object. CryptHashData or
  ' CryptHashSessionKey is then used to add data or session keys to the
  ' hash object.
  Private Declare Function CryptVerifySignature Lib "advapi32.dll" _
          Alias "CryptVerifySignatureA" (ByVal hhash As Long, _
          ByVal pData As Long, ByVal datalength As Long, _
          ByVal PublicKey As Long, ByVal Description As Long, _
          ByVal dwFlags As Long) As Long

  ' The CryptGetHashParam function retrieves data that governs the
  ' operations of a hash object. The actual hash value can be
  ' retrieved by using this function.
  Private Declare Function CryptGetHashParam Lib "advapi32.dll" _
          (ByVal hhash As Long, ByVal dwParam As Long, ByVal pbData As String, _
          pdwDataLen As Long, ByVal dwFlags As Long) As Long
  
  ' Alias of CryptGetHashParam
  Private Declare Function CryptGetHashParamSize Lib "advapi32.dll" _
          Alias "CryptGetHashParam" (ByVal hhash As Long, _
          ByVal dwParam As Long, pbData As Long, _
          dwDataLength As Long, ByVal dwFlags As Long) As Long

  'The CryptDestroyHash function destroys the hash object referenced
  ' by the hHash parameter. After a hash object has been destroyed,
  ' it can no longer be used.  The destruction of hash objects after
  ' their use is finished is recommended for security reasons.
  Private Declare Function CryptDestroyHash Lib "advapi32.dll" _
          (ByVal hhash As Long) As Long
    
  ' The CryptAcquireContext function is used to acquire a handle to a
  ' particular key container within a particular cryptographic service
  ' provider (CSP). This returned handle can then be used to make
  ' calls to the selected CSP.  This function performs two operations.
  ' It first attempts to find a CSP with the characteristics described
  ' in the dwProvType and pszProvider parameters. If the CSP is found,
  ' the function attempts to find a key container within the CSP
  ' matching the name specified by the pszContainer parameter.  With the
  ' appropriate setting of dwFlags, this function can also create and
  ' destroy key containers.
  Private Declare Function CryptAcquireContext Lib "advapi32.dll" _
          Alias "CryptAcquireContextA" (ByRef phProv As Long, _
          ByVal pszContainer As String, ByVal pszProvider As String, _
          ByVal dwProvType As Long, ByVal dwFlags As Long) As Long

  ' The CryptReleaseContext function releases the handle of a
  ' cryptographic service provider (CSP) and a key container. At each
  ' call to this function, the reference count on the CSP is reduced
  ' by one. When the reference count reaches zero, the context is fully
  ' released and it can no longer be used by any function in the application.
  ' An application calls this function after finishing the use of the CSP.
  ' After this function is called, the released CSP handle is no longer