AES192_Update

AES192_Update carries out the AES transformation function on a byte array according to the direction and mode set up by an earlier call to AES192_Init or AES192_InitHex.

VB6/VBA Syntax

nRet = AES192_Update(hContext, abData(0), nDataLen)

Parameters

hContext

[in] Long handle to the AES context set up by an earlier call to AES192_Init or AES192_InitHex.

abData

[in/out] Byte array containing the input to be processed by the AES function and to receive the output.

nDataLen

[in] Long containing length of the data in bytes.

C/C++ Syntax

Returns (VB6/C)

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

.NET Equivalent

Aes192.Update Method (Byte[])

Remarks

The input array abData must be a multiple of the block size of 16 bytes long. If not, an error code will be returned. Note that the output overwrites the input.

Example

This example carries out the third (I=2) Monte Carlo MOVS test in CBC encrypt mode. (Ref: AES Candidate Algorithm Submissions, update 17 Feb 1998, file cbc_e_m.txt [RIJNVALS]).

    Dim nRet As Long
    Dim hContext As Long
    Dim abBlock() As Byte
    Dim abKey() As Byte
    Dim abCorrect() As Byte
    Dim j As Integer
    
' File: ecb_d_m.txt
' KEYSIZE=192 I=2
' KEY=EF334C87288C43DE84E276D5CCD586228C8EA3A264D2DB0E
' CT=CC01684BE9B29ED01EA7923E7D2380AA
' PT=8726B4E66D6B8FBAA22D42981A5A40CC
     ' Convert to Byte format
    abKey = cnvBytesFromHexStr("EF334C87288C43DE84E276D5CCD586228C8EA3A264D2DB0E")
    abBlock = cnvBytesFromHexStr("CC01684BE9B29ED01EA7923E7D2380AA")
    abCorrect = cnvBytesFromHexStr("8726B4E66D6B8FBAA22D42981A5A40CC")
    
    Debug.Print "AES Monte Carlo ECB Mode Decrypt:"
    Debug.Print "KY="; cnvHexStrFromBytes(abKey)
    Debug.Print "CT="; cnvHexStrFromBytes(abBlock)
    
    hContext = AES192_Init(abKey(0), DECRYPT, "ECB", 0)
    If hContext = 0 Then
        MsgBox "Failed to set context", vbCritical
        Exit Function
    End If
    ' Do 10,000 times
    For j = 0 To 9999
        nRet = AES192_Update(hContext, abBlock(0), 16)
    Next
    Debug.Print "PT="; cnvHexStrFromBytes(abBlock)
    Debug.Print "OK="; cnvHexStrFromBytes(abCorrect)
    nRet = AES192_Final(hContext)
    
    Debug.Assert (StrConv(abCorrect, vbUnicode) = StrConv(abBlock, vbUnicode))

This should result in output as follows:

AES Monte Carlo ECB Mode Decrypt:
KY=EF334C87288C43DE84E276D5CCD586228C8EA3A264D2DB0E
CT=CC01684BE9B29ED01EA7923E7D2380AA
PT=8726B4E66D6B8FBAA22D42981A5A40CC
OK=8726B4E66D6B8FBAA22D42981A5A40CC

See Also

AES192_Init AES192_InitHex AES192_UpdateHex AES192_Final

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