VFP生成随机加密密钥

#DEFINE CALG_DES 0x00006601  && 56 bits
#DEFINE CALG_3DES 0x00006603  && 168 bits

* 40, 128 bits
#DEFINE CALG_RC2 0x00006602
#DEFINE CALG_RC4 0x00006801

* 384 bits to 16,384 bits in 8-bit increments.
#DEFINE CALG_RSA_KEYX 0x0000a400
#DEFINE CALG_RSA_SIGN 0x00002400

LOCAL obj as CryptKeyHelper
obj = CREATEOBJECT("CryptKeyHelper")

IF NOT obj.GenerateRandomKey(CALG_RC4, 128)
  ? "GenerateRandomKey failed:",;
    TRANSFORM(obj.LastWin32Error, "@0")
  RETURN
ENDIF

LOCAL cKeyFile
cKeyFile = "samplekey.txt"

IF NOT obj.ExportKeyToFile(m.cKeyFile)
  ? "ExportKeyToFile failed:",;
    TRANSFORM(obj.LastWin32Error, "@0")
  RETURN
ENDIF

MODIFY FILE (m.cKeyFile)

IF NOT obj.ImportKeyFromFile(m.cKeyFile)
  ? "ImportKeyFromFilefailed:",;
    TRANSFORM(obj.LastWin32Error, "@0")
ENDIF

? "Key imported from file successfully"
* end of main

DEFINE CLASS CryptKeyHelper as Session
#DEFINE CRYPT_VERIFYCONTEXT 0xf0000000
#DEFINE PROV_RSA_FULL 1
#DEFINE CRYPT_EXPORTABLE 1

#DEFINE NTE_BAD_KEY 0x80090003
#DEFINE NTE_BAD_ALGID 0x80090008
#DEFINE NTE_BAD_FLAGS 0x80090009

#DEFINE PLAINTEXTKEYBLOB 8

PROTECTED hProv, hKey
  hProv = 0
  hKey = 0
  LastWin32Error=0
  
PROCEDURE Init
  THIS.declare
  IF NOT THIS.GetContext()
    RETURN .F.
  ENDIF

PROCEDURE Destroy
  THIS.DestroyKey
  THIS.ReleaseContext

PROCEDURE GenerateRandomKey
LPARAMETERS nAlgId, nKeyBits
  THIS.DestroyKey
  THIS.LastWin32Error = 0

  LOCAL nFlags, hKey
  
  IF EMPTY(m.nKeyBits)
    nKeyBits = 40
  ENDIF
  
  nFlags = BITOR(CRYPT_EXPORTABLE,;
    BITLSHIFT(nKeyBits, 16))

  hKey = 0
  
  IF CryptGenKey(;
    THIS.hProv, m.nAlgId, m.nFlags, @hKey) > 0
    THIS.hKey = m.hKey
    RETURN .T.
  ENDIF

  THIS.LastWin32Error = GetLastError()
RETURN .F.

PROCEDURE ImportKeyFromFile
LPARAMETERS cFilename
  LOCAL cBuffer, hKey
  
  cBuffer = FILETOSTR(m.cFilename)
  hKey = 0
  
  IF CryptImportKey(;
    THIS.hProv, m.cBuffer, LEN(m.cBuffer),;
    0, CRYPT_EXPORTABLE, @hKey) > 0
  
    THIS.DestroyKey
    THIS.hKey = m.hKey
    RETURN .T.
  ENDIF

  THIS.LastWin32Error = GetLastError()
RETURN .F.

PROCEDURE ExportKeyToFile
LPARAMETERS cFilename
  IF THIS.hKey = 0
    RETURN .F.
  ENDIF
  
  LOCAL nBlobLength, cBuffer
  nBlobLength = 0

  = CryptExportKey(;
    THIS.hKey, 0, PLAINTEXTKEYBLOB,;
    0, 0, @nBlobLength)
    
  IF nBlobLength = 0
    THIS.LastWin32Error = GetLastError()
    RETURN .F.
  ENDIF
    
  cBuffer = REPLICATE(CHR(0), m.nBlobLength)

  IF CryptExportKey(;
    THIS.hKey, 0, PLAINTEXTKEYBLOB, 0,;
    @cBuffer, @nBlobLength) > 0

    STRTOFILE(m.cBuffer, m.cFilename)
    RETURN .T.
  ENDIF
  
  THIS.LastWin32Error = GetLastError()
RETURN .F.

PROTECTED PROCEDURE ReleaseContext
  = CryptReleaseContext(THIS.hProv, 0)
  THIS.hProv = 0

PROTECTED PROCEDURE DestroyKey
  IF THIS.hKey <> 0
    = CryptDestroyKey(THIS.hKey)
    THIS.hKey= 0
  ENDIF

PROTECTED PROCEDURE GetContext
* get handle to the crypto provider
  LOCAL hProv
  hProv = 0
  IF CryptAcquireContext(@hProv, NULL, NULL,;
    PROV_RSA_FULL, CRYPT_VERIFYCONTEXT) = 0
    RETURN .F.
  ENDIF
  THIS.hProv = m.hProv
RETURN .T.

PROTECTED PROCEDURE declare
  DECLARE INTEGER GetLastError IN kernel32

  DECLARE INTEGER CryptAcquireContext IN advapi32;
    INTEGER @hProvHandle, STRING cContainer, ;
    STRING cProvider, INTEGER nProvType, INTEGER nFlags

  DECLARE INTEGER CryptReleaseContext IN advapi32;
    INTEGER hProvHandle, INTEGER nReserved

  DECLARE INTEGER CryptGenKey IN advapi32;
    INTEGER hProv, INTEGER Algid,;
    INTEGER dwFlags, INTEGER @phKey

  DECLARE INTEGER CryptExportKey IN advapi32;
    INTEGER hKey, INTEGER hExpKey,;
    INTEGER dwBlobType, INTEGER dwFlags,;
    STRING @pbData, INTEGER @pdwDataLen

  DECLARE INTEGER CryptImportKey IN advapi32;
    INTEGER hProv, STRING @pbData,;
    INTEGER dwDataLen, INTEGER hPubKey,;
    INTEGER dwFlags, INTEGER @phKey

  DECLARE INTEGER CryptDestroyKey IN advapi32;
    INTEGER hKey

ENDDEFINE