CryptoSys API Library Manual

BLF_Bytes

Encrypts or decrypts an array of Bytes in one step in Electronic Codebook (EBC) mode.

VB6/VBA Syntax

Public Declare Function BLF_Bytes Lib "diCryptoSys.dll" (ByRef abOutput As Byte, ByRef abData As Byte, ByVal nDataLen As Long, ByRef abKey As Byte, ByVal nKeyLen As Long, ByVal bEncrypt As Boolean) As Long

nRet = BLF_Bytes(abOutput(0), abData(0), nDataLen, abKey(0), nKeyLen, bEncrypt)

Parameters

abOutput
[out] Byte array of sufficient length to receive the output.
abData
[in] Byte array containing the input data.
nDataLen
[in] Long equal to length of the input data in bytes.
abKey
[in] Byte array containing the key.
nKeyLen
[in] Long equal to length of the key in bytes.
bEncrypt
[in] Boolean direction flag: set as True to encrypt or False to decrypt.

C/C++ Syntax

long _stdcall BLF_Bytes(unsigned char *output, const unsigned char *input, long nbytes, const unsigned char *key, long keyBytes, int bEncrypt);

Returns (VB6/C)

Long: If successful, the return value is 0; otherwise it returns a non-zero error code.

Remarks

The input data abData must be an exact multiple of 8 bytes long. If not, an error code will be returned. The key abKey can be any length between 1 and 56 bytes (448 bits). The output array abOutput must be at least nDataLen bytes long. abOutput and abData may be the same.

VB6/VBA users: Note the '(0)' after the byte array variables.

Example

    Dim nRet As Long
    Dim strInput As String
    Dim strKey As String
    Dim sCorrect As String
    Dim nKeyLen As Long
    Dim abKey() As Byte
    Dim abOutput() As Byte
    Dim abData() As Byte
    Dim nDataLen As Long
    
    ' Define test vectors in hex
    strKey = "FEDCBA9876543210"
    strInput = "0123456789ABCDEF0123456789ABCDEF"
    sCorrect = "0ACEAB0FC6A0A28D0ACEAB0FC6A0A28D"
    
    ' Convert to byte arrays and compute lengths
    nKeyLen = Len(strKey) \ 2
    abKey = cnvBytesFromHexStr(strKey)
    nDataLen = Len(strInput) \ 2
    abData = cnvBytesFromHexStr(strInput)
    
    ' Dimension array for output
    ReDim abOutput(nDataLen - 1)
    
    Debug.Print "KY="; cnvHexStrFromBytes(abKey)
    Debug.Print "PT="; cnvHexStrFromBytes(abData)
    ' Encrypt in one-off process
    nRet = BLF_Bytes(abOutput(0), abData(0), nDataLen, abKey(0), nKeyLen, ENCRYPT)
    Debug.Print "CT="; cnvHexStrFromBytes(abOutput), nRet
    Debug.Print "OK="; sCorrect
    
    ' Now decrypt back
    nRet = BLF_Bytes(abData(0), abOutput(0), nDataLen, abKey(0), nKeyLen, DECRYPT)
    Debug.Print "P'="; cnvHexStrFromBytes(abData), nRet

This should result in output as follows:

KY=FEDCBA9876543210
PT=0123456789ABCDEF0123456789ABCDEF
CT=0ACEAB0FC6A0A28D0ACEAB0FC6A0A28D        0 
OK=0ACEAB0FC6A0A28D0ACEAB0FC6A0A28D
P'=0123456789ABCDEF0123456789ABCDEF        0 

See Also

BLF_BytesMode BLF_B64Mode

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