3DES Encryption, ECB, CBC modes

3DES encryption. The Chilkat encryption component supports Triple-DES in both ECB (Electronic Cookbook) and CBC (Cipher-Block Chaining) cipher modes.

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Dim crypt As New Chilkat.Crypt2()

Dim success As Boolean
success = crypt.UnlockComponent("Anything for 30-day trial")
If (success <> true) Then
    MsgBox("Crypt component unlock failed")
    Exit Sub
End If


'  Specify 3DES for the encryption algorithm:
crypt.CryptAlgorithm = "3des"

'  CipherMode may be "ecb" or "cbc"
crypt.CipherMode = "cbc"

'  KeyLength must be 192.  3DES is technically 168-bits;
'  the most-significant bit of each key byte is a parity bit,
'  so we must indicate a KeyLength of 192, which includes
'  the parity bits.
crypt.KeyLength = 192

'  The padding scheme determines the contents of the bytes
'  that are added to pad the result to a multiple of the
'  encryption algorithm's block size.  3DES has a block
'  size of 8 bytes, so encrypted output is always
'  a multiple of 8.
crypt.PaddingScheme = 0

'  EncodingMode specifies the encoding of the output for
'  encryption, and the input for decryption.
'  It may be "hex", "url", "base64", or "quoted-printable".
crypt.EncodingMode = "hex"

'  An initialization vector is required if using CBC or CFB modes.
'  ECB mode does not use an IV.
'  The length of the IV is equal to the algorithm's block size.
'  It is NOT equal to the length of the key.
Dim ivHex As String
ivHex = "0001020304050607"
crypt.SetEncodedIV(ivHex,"hex")

'  The secret key must equal the size of the key.  For
'  3DES, the key must be 24 bytes (i.e. 192-bits).
Dim keyHex As String
keyHex = "000102030405060708090A0B0C0D0E0F0001020304050607"
crypt.SetEncodedKey(keyHex,"hex")

'  Encrypt a string...
'  The input string is 44 ANSI characters (i.e. 44 bytes), so
'  the output should be 48 bytes (a multiple of 8).
'  Because the output is a hex string, it should
'  be 96 characters long (2 chars per byte).
Dim encStr As String
encStr = crypt.EncryptStringENC("The quick brown fox jumps over the lazy dog.")
MsgBox(encStr)

'  Now decrypt:
Dim decStr As String
decStr = crypt.DecryptStringENC(encStr)
MsgBox(decStr)