AES256_Bytes

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

@deprecated use AES256_BytesMode with strMode="ECB".

VBA/VB6 Syntax

nRet = AES256_Bytes(lpOutput(0), abData(0), nDataLen, abKey(0), bEncrypt) ' Note the "(0)" after the byte array parameters

C/C++ Syntax

Parameters

lpOutput

[out] array of sufficient length to receive the output.

lpInput

[in] array containing the input data.

nBytes

[in] equal to length of the input data in bytes.

lpKey

[in] array containing the key.

fEncrypt

[in] direction flag: set as ENCRYPT (True) to encrypt or DECRYPT (False) to decrypt.

Returns (VBA/C)

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

.NET Equivalent

Aes256.Encrypt Method (Byte[], Byte[], Mode, Byte[])
Aes256.Decrypt Method (Byte[], Byte[], Mode, Byte[])
with mode=Mode.ECB.

Remarks

The input array lpData must be a multiple of the block size of 16 bytes long. If not, an error code will be returned. The key array abKey() must be exactly 32 bytes long (i.e. 256 bits). The output array lpOutput must be at least as long as the input array. lpOutput and lpData may be the same.

This function is equivalent to

nRet = AES256_BytesMode(lpOutput(0), abData(0), nDataLen, abKey(0), bEncrypt, "ECB", 0)

Example

    Dim nRet As Long
    Dim strHexKey As String
    Dim sPlain As String
    Dim sCipher As String
    Dim abBlock() As Byte
    Dim abKey() As Byte
    Dim abPlain() As Byte
    Dim abCipher() As Byte
    Dim nBytes As Long
    
'FIPS-197
'C.3 AES-256 (Nk=8, Nr=14)
'PLAINTEXT: 00112233445566778899aabbccddeeff
'KEY: 000102030405060708090a0b0c0d0e0f101112131415161718191a1b1c1d1e1f
' round[14].output 8ea2b7ca516745bfeafc49904b496089

    strHexKey = _
    "000102030405060708090a0b0c0d0e0f101112131415161718191a1b1c1d1e1f"
    sPlain = "00112233445566778899aabbccddeeff"
    sCipher = "8ea2b7ca516745bfeafc49904b496089"
    
    ' Convert input to bytes
    abKey = cnvBytesFromHexStr(strHexKey)
    abPlain = cnvBytesFromHexStr(sPlain)
    abCipher = cnvBytesFromHexStr(sCipher)
    
    abBlock = abPlain
    nBytes = UBound(abBlock) - LBound(abBlock) + 1
    Debug.Print "KY=" & cnvHexStrFromBytes(abKey)
    Debug.Print "PT=" & cnvHexStrFromBytes(abBlock)
    ' Encrypt in one-off process
    nRet = AES256_Bytes(abBlock(0), abBlock(0), nBytes, abKey(0), ENCRYPT)
    Debug.Print "CT=" & cnvHexStrFromBytes(abBlock)
    Debug.Print "OK=" & cnvHexStrFromBytes(abCipher)
    Debug.Assert (StrConv(abBlock, vbUnicode) = StrConv(abCipher, vbUnicode))
    
    ' Now decrypt back to plain text
    nRet = AES256_Bytes(abBlock(0), abBlock(0), nBytes, abKey(0), DECRYPT)
    Debug.Print "P'=" & cnvHexStrFromBytes(abBlock)
    Debug.Assert (StrConv(abBlock, vbUnicode) = StrConv(abPlain, vbUnicode))

This should result in output as follows:

KY=000102030405060708090A0B0C0D0E0F101112131415161718191A1B1C1D1E1F
PT=00112233445566778899AABBCCDDEEFF
CT=8EA2B7CA516745BFEAFC49904B496089
OK=8EA2B7CA516745BFEAFC49904B496089
P'=00112233445566778899AABBCCDDEEFF

See Also

AES256_BytesMode

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