vb md5加密exe文件原代码，高分送顶者！
请问vb md5加密exe文件的原理？是将 exe----byte----string----md5(string)吗，这样将exe-------byte--------string会很慢哦，谁有原代码，给一份，谢谢哦！
[解决办法]
md5 是单向散列（Hash）算法，不能用来加密。它最常见的用途是数字签名。
[解决办法]
md5加密了，不能还原，用RC4可以。
[解决办法]
哦,有私钥是可以还原的
[解决办法]
我记得不能还原啊
[解决办法]
学习
[解决办法]
我有个MD5的类，也是网上找的，试一试吧。
Option Explicit
'/******************************************************************************
' * Copyright (C) 2000 by Robert Hubley. *
' * All rights reserved. *
' * *
' * This software is provided ``AS IS ' and any express or implied *
' * warranties, including, but not limited to, the implied warranties of *
' * merchantability and fitness for a particular purpose, are disclaimed. *
' * In no event shall the authors be liable for any direct, indirect, *
' * incidental, special, exemplary, or consequential damages (including, but *
' * not limited to, procurement of substitute goods or services; loss of use, *
' * data, or profits; or business interruption) however caused and on any *
' * theory of liability, whether in contract, strict liability, or tort *
' * (including negligence or otherwise) arising in any way out of the use of *
' * this software, even if advised of the possibility of such damage. *
' * *
' ******************************************************************************
'
' CLASS: MD5
'
' DESCRIPTION:
' This is a class which encapsulates a set of MD5 Message Digest functions.
' MD5 algorithm produces a 128 bit digital fingerprint (signature) from an
' dataset of arbitrary length. For details see RFC 1321 (summarized below).
' This implementation is derived from the RSA Data Security, Inc. MD5 Message-Digest
' algorithm reference implementation (originally written in C)
'
' AUTHOR:
' Robert M. Hubley 12/1999
'
'
' NOTES:
' Network Working Group R. Rivest
' Request for Comments: 1321 MIT Laboratory for Computer Science
' and RSA Data Security, Inc.
' April 1992
'
'
' The MD5 Message-Digest Algorithm
'
' Summary
'
' This document describes the MD5 message-digest algorithm. The
' algorithm takes as input a message of arbitrary length and produces
' as output a 128-bit "fingerprint " or "message digest " of the input.
' It is conjectured that it is computationally infeasible to produce
' two messages having the same message digest, or to produce any
' message having a given prespecified target message digest. The MD5
' algorithm is intended for digital signature applications, where a
' large file must be "compressed " in a secure manner before being
' encrypted with a private (secret) key under a public-key cryptosystem
' such as RSA.
'
' The MD5 algorithm is designed to be quite fast on 32-bit machines. In
' addition, the MD5 algorithm does not require any large substitution
' tables; the algorithm can be coded quite compactly.
'
' The MD5 algorithm is an extension of the MD4 message-digest algorithm
' 1,2]. MD5 is slightly slower than MD4, but is more "conservative " in
' design. MD5 was designed because it was felt that MD4 was perhaps
' being adopted for use more quickly than justified by the existing
' critical review; because MD4 was designed to be exceptionally fast,
' it is "at the edge " in terms of risking successful cryptanalytic
' attack. MD5 backs off a bit, giving up a little in speed for a much
' greater likelihood of ultimate security. It incorporates some
' suggestions made by various reviewers, and contains additional
' optimizations. The MD5 algorithm is being placed in the public domain
' for review and possible adoption as a standard.
'
' RFC Author:
' Ronald L.Rivest
' Massachusetts Institute of Technology
' Laboratory for Computer Science
' NE43 -324545 Technology Square
' Cambridge, MA 02139-1986
' Phone: (617) 253-5880
' EMail: Rivest@ theory.lcs.mit.edu
'
'
'
' CHANGE HISTORY:
'
' 0.1.0 RMH 1999/12/29 Original version
'
'
'=
'= Class Constants
'=
Private Const OFFSET_4 = 4294967296#
Private Const MAXINT_4 = 2147483647
Private Const S11 = 7
Private Const S12 = 12
Private Const S13 = 17
Private Const S14 = 22
Private Const S21 = 5
Private Const S22 = 9
Private Const S23 = 14
Private Const S24 = 20
Private Const S31 = 4
Private Const S32 = 11
Private Const S33 = 16
Private Const S34 = 23
Private Const S41 = 6
Private Const S42 = 10
Private Const S43 = 15
Private Const S44 = 21
'=
'= Class Variables
'=
Private State(4) As Long
Private ByteCounter As Long
Private ByteBuffer(63) As Byte
'=
'= Class Properties
'=
Property Get RegisterA() As String
RegisterA = State(1)
End Property
Property Get RegisterB() As String
RegisterB = State(2)
End Property
Property Get RegisterC() As String
RegisterC = State(3)
End Property
Property Get RegisterD() As String
RegisterD = State(4)
End Property
'=
'= Class Functions
'=
