Encrypts or decrypts a file using a specified mode. The key and initialization vector are passed as hexadecimal strings.
Public Declare Function AES256_FileHex Lib "diCryptoSys.dll"
(ByVal strFileOut As String, ByVal strFileIn As String,
ByVal strHexKey As String,
ByVal bEncrypt As Boolean, ByVal strMode As String, ByVal strHexIV As String) As Long
nRet = AES256_FileHex(strFileOut, strFileIn, strHexKey, bEncrypt, strMode, strHexIV)
long __stdcall AES256_FileHex(const char *szFileOut, const char *szFileIn, const char *szKey, int fEncrypt, const char *szMode, const char *szIV);
If successful, the return value is 0; otherwise it returns a non-zero error code.
Aes256.FileEncrypt Method (String, String, String, Mode, String)
Aes256.FileDecrypt Method (String, String, String, Mode, String)
The key string szHexKey
must be exactly 64 hexadecimal characters long
(i.e. representing exactly 32 bytes/256 bits).
The initialization vector szHexIV
must be exactly 32 hexadecimal characters long
(i.e. representing exactly the block size of 16 bytes), except for ECB mode, where it is ignored (use "").
The output file szFileOut will be overwritten without warning.
If there is an error [new in version 3.3], the output file will not exist.
The input and output filepaths must not be the same.
In ECB and CBC modes, a padding string will be added or assumed according to the method outlined in Section 6.3 of
[CMS],
which is the same as the padding method in [PKCS7] and [PKCS5].
Note that even though the parameters are in hexadecimal-encoded form, the encrypted file is still binary.
This example will encrypt the file "bigfile.dat" in CBC mode using the 256-bit key
0x000102030405060708090a0b0c0d0e0f101112131415161718191a1b1c1d1e1f and initialization vector
0x0123456789abcdef0123456789abcdef. The output file "bigfile.cbc" will be created or
overwritten.
Dim nRet As Long
nRet = AES256_FileHex("bigfile.cbc", "bigfile.dat", _
"000102030405060708090a0b0c0d0e0f101112131415161718191a1b1c1d1e1f", _
ENCRYPT, "CBC", "0123456789abcdef0123456789abcdef")
If nRet <> 0 Then
Debug.Print "AES256_FileHex failed: " & apiErrorLookup(nRet)
Else
Debug.Print "AES256_FileHex encrypted file OK"
End If