CryptoSys API Library Manual

MD5_AddBytes

Adds an array of bytes to the digest.

VB6/VBA Syntax

Public Declare Function MD5_AddBytes Lib "diCryptoSys.dll" (ByVal hContext As Long, ByRef abData As Byte, ByVal nDataLen As Long) As Long

nRet = MD5_AddBytes(hContext, abData(0), nDataLen)

Parameters

hContext
[in] Long handle to the MD5 context.
abData
[in] Byte array containing the next part of the message to be hashed.
nDataLen
[in] Long containing the number of bytes in the array

C/C++ Syntax

long _stdcall MD5_AddBytes(long ctx_handle, const unsigned char *bytes, long len);

Returns (VB6/C)

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

.NET Equivalent

Md5.AddData Method (Byte[])

Remarks

The handle to the context hContext must have been set up with a prior call to MD5_Init. This function may be called many times before creating the final message digest with MD5_HexDigest. MD5_AddString may also be called.

Example

This example creates the hash of the three-character string "abc" using a mixture of calls to MD5_AddBytes and MD5_AddString.

    Dim nRet As Long
    Dim strDigest As String
    Dim hContext As Long
    Dim abData(2) As Byte

    ' Set context handle
    hContext = MD5_Init()
    ' Remember to check for an invalid handle
    If hContext = 0 Then
        MsgBox "Failed to set context"
        Exit Function
    End If

    ' Set up a test array of bytes
    abData(0) = Asc("a")
    abData(1) = &H62    ' same as Asc("b")
    ' Add mixture of bytes and strings
    nRet = MD5_AddBytes(hContext, abData(0), 2)
    nRet = MD5_AddString(hContext, "c")

    ' Set strDigest to be 32 chars
    strDigest = String(32, " ")
    nRet = MD5_HexDigest(strDigest, hContext)
    Debug.Print strDigest

This should result in output as follows:

900150983cd24fb0d6963f7d28e17f72

See Also

MD5_Init MD5_AddString MD5_HexDigest MD5_Reset

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