delphi 微信消息加密解密单元

{*****************************************************************************}

{ }

{ 泛思微平台 }

{ }

{ 微信消息加密解密单元，使用DelphiXE2版本编写 }

{ 作者：Delphi力量 }

{ QQ：404328970 }

{ EMail: heblxy@163.com }

{ Blog：www.cnblogs.com/dpower }

{ 参考链接： }

{ http://mp.weixin.qq.com/wiki/14/70e73cedf9fd958d2e23264ba9333ad2.html }

{ }

{*****************************************************************************}

unit uWxMsgCrypt;

interface

uses

System.Classes, System.SysUtils;

type

WXBizMsgCryptErrorCode = (

WXBizMsgCrypt_OK = 0,

WXBizMsgCrypt_ValidateSignature_Error = -40001,

WXBizMsgCrypt_ParseXml_Error = -40002,

WXBizMsgCrypt_ComputeSignature_Error = -40003,

WXBizMsgCrypt_IllegalAesKey = -40004,

WXBizMsgCrypt_ValidateAppid_Error = -40005,

WXBizMsgCrypt_EncryptAES_Error = -40006,

WXBizMsgCrypt_DecryptAES_Error = -40007,

WXBizMsgCrypt_IllegalBuffer = -40008,

WXBizMsgCrypt_EncodeBase64_Error = -40009,

WXBizMsgCrypt_DecodeBase64_Error = -40010

);

///

/// 提供微信加密消息解密和微信明文消息加密功能

///

TWxMsgCrypt = class

private

function CreateRandCode(codeLen: Integer): string;

function AES_decrypt(const sEncodingAESKey, sMsgEncrypt: string; var cpid: string): string;

function AES_encrypt(const sEncodingAESKey, sMsg, cpid: string): string;

public

///

/// 解密微信消息

///

/// Token，看公众号设置

/// 时间戳，随微信消息一起传入，可以通过Url参数获取

/// 随机字符串，随微信消息一起传入，可以通过Url参数获取

/// 微信消息xml的Encrypt字段内容

/// 签名，随微信消息一起传入，可以通过Url参数获取

/// AppID，看公众号设置

/// EncodingAESKey，看公众号设置

/// sMsg: 解密后的Encrypt字段内容原文，当return返回WXBizMsgCrypt_OK时有效

/// 成功WXBizMsgCrypt_OK，失败返回对应的错误码

function DecryptMsg(const sToken, sTimeStamp, sNonce, sMsgEncrypt, sSigture,

sAppID, sEncodingAESKey: string; var sMsg: string): WXBizMsgCryptErrorCode;

///

/// 加密微信消息

///

/// 全部xml内容（明文）

/// AppID，看公众号设置

/// EncodingAESKey，看公众号设置

/// sMsgEncrypt: 输出的是加密后的全部xml（可以直接发送无需再编组xml），当return返回WXBizMsgCrypt_OK时有效

/// 成功WXBizMsgCrypt_OK，失败返回对应的错误码

function EncryptMsg(const sMsg, sToken, sAppID, sEncodingAESKey: string;

var sMsgEncrypt: string): WXBizMsgCryptErrorCode;

end;

implementation

uses

CnSHA1, EncdDecd, CnAES, System.Math, uWxGlobal;

{ TWxMsgCrypt }

function TWxMsgCrypt.AES_decrypt(const sEncodingAESKey, sMsgEncrypt: string; var cpid: string): string;

var

aEncodingAESKeyStr, sInput: AnsiString;

aEncodingAESKeyBts, IvBts, InputBts: TBytes;

InputStream, DecodeStream: TMemoryStream;

AesKey: TAESKey256;

Iv: TAESBuffer;

P: PByteArray;

iLen, iDecodeDataLen: Integer;

bMsg, bAppid: TBytes;

function GetRealDataLenWithoutKCS7Bytes: Integer;

var

lstBt: Byte;

block_size, AllKCS7ByteCount: Integer;

begin

block_size := 32;

lstBt := P^[DecodeStream.Size - 1];

AllKCS7ByteCount := block_size - (block_size - Ord(lstBt));

if (AllKCS7ByteCount > 0) and (AllKCS7ByteCount < DecodeStream.Size) then

begin

if P^[DecodeStream.Size - AllKCS7ByteCount] = lstBt then

Result := DecodeStream.Size - AllKCS7ByteCount

else

Result := DecodeStream.Size;

end else

Result := DecodeStream.Size;

end;

begin

try

aEncodingAESKeyStr := AnsiString(sEncodingAESKey + '=');

aEncodingAESKeyBts := DecodeBase64(aEncodingAESKeyStr);

except

raise Exception.Create('1');

end;

try

SetLength(IvBts, 16);

Move(aEncodingAESKeyBts[0], IvBts[0], 16);

// aes.KeySize = 256; aes.BlockSize = 128; aes.Mode = CipherMode.CBC; aes.Padding = PaddingMode.None;

sInput := AnsiString(sMsgEncrypt);

InputBts := DecodeBase64(sInput);

InputStream := TMemoryStream.Create;

DecodeStream := TMemoryStream.Create;

try

InputStream.Write(InputBts[0], Length(InputBts));

Move(aEncodingAESKeyBts[0], AesKey, Length(aEncodingAESKeyBts));

Move(IvBts[0], Iv, Length(IvBts));

InputStream.Position := 0;

DecryptAESStreamCBC(InputStream, 0,

AesKey, Iv, DecodeStream);

P := PByteArray(DecodeStream.Memory);

iDecodeDataLen := GetRealDataLenWithoutKCS7Bytes;

iLen := P^[16] shl 24 + P^[17] shl 16 + P^[18] shl 8 + P^[19];

SetLength(bMsg, iLen);

SetLength(bAppid, iDecodeDataLen - 20 - iLen);

Move(P^[20], bMsg[0], iLen);

Move(P^[20 + iLen], bAppid[0], iDecodeDataLen - 20 - iLen);

Result := TEncoding.UTF8.GetString(bMsg);

cpid := TEncoding.UTF8.GetString(bAppid);

finally

InputStream.Free;

DecodeStream.Free;

end;

except

raise Exception.Create('2');

end;

function TWxMsgCrypt.AES_encrypt(const sEncodingAESKey, sMsg,

cpid: string): string;

var

aEncodingAESKeyStr: AnsiString;

aEncodingAESKeyBts, IvBts, bRand, bAppid, btmpMsg, bMsg, bMsgLen, msg, pad: TBytes;

Randcode: string;

AesKey: TAESKey256;

Iv: TAESBuffer;

InputStream, OutputStream: TMemoryStream;

function CreateRandCode(codeLen: Integer): string;

var

codeSerial, code: string;

strLst: TStringList;

randValue, i: Integer;

begin

codeSerial := '2,3,4,5,6,7,a,c,d,e,f,h,i,j,k,m,n,p,r,s,t,A,C,D,E,F,G,H,J,K,M,N,P,Q,R,S,U,V,W,X,Y,Z';

if (codeLen = 0) then

codeLen := 16;

strLst := TStringList.Create;

try

ExtractStrings([','], [], PChar(codeSerial), strLst);

code := '';

Randomize;

for i := 0 to codeLen - 1 do

begin

randValue := Random(strLst.Count);

code := code + strLst[randValue];

end;

Result := code;

finally

strLst.Free;

end;

function KCS7Encoder(text_length: Integer): TBytes;

var

block_size, amount_to_pad: Integer;

pad_chr: Char;

tmp: string;

i: Integer;

begin

block_size := 32;

// 计算需要填充的位数

amount_to_pad := block_size - (text_length mod block_size);

if (amount_to_pad = 0) then

amount_to_pad := block_size;

// 获得补位所用的字符

pad_chr := Chr(amount_to_pad);

tmp := '';

for i := 0 to amount_to_pad - 1 do

tmp := tmp + pad_chr;

Result := BytesOf(tmp);

end;

begin

aEncodingAESKeyStr := AnsiString(sEncodingAESKey + '=');

aEncodingAESKeyBts := DecodeBase64(aEncodingAESKeyStr);

SetLength(IvBts, 16);

Move(aEncodingAESKeyBts[0], IvBts[0], 16);

Randcode := CreateRandCode(16);

bRand := TEncoding.UTF8.GetBytes(Randcode);

bAppid := TEncoding.UTF8.GetBytes(cpid);

btmpMsg := TEncoding.UTF8.GetBytes(sMsg);

SetLength(bMsgLen, 4);

bMsgLen[0] := (Length(btmpMsg) shr 24) and $FF;

bMsgLen[1] := (Length(btmpMsg) shr 16) and $FF;

bMsgLen[2] := (Length(btmpMsg) shr 8) and $FF;

bMsgLen[3] := Length(btmpMsg) and $FF;

SetLength(bMsg, Length(bRand) + Length(bAppid) + Length(btmpMsg) + Length(bMsgLen));

Move(bRand[0], bMsg[0], Length(bRand));

Move(bMsgLen[0], bMsg[Length(bRand)], Length(bMsgLen));

Move(btmpMsg[0], bMsg[Length(bRand) + Length(bMsgLen)], Length(btmpMsg));

Move(bAppid[0], bMsg[Length(bRand) + Length(bMsgLen) + Length(btmpMsg)], Length(bAppid));

{$REGION '自己进行PKCS7补位'}

SetLength(msg, Length(bMsg) + 32 - Length(bMsg) mod 32);

Move(bMsg[0], msg[0], Length(bMsg));

pad := KCS7Encoder(Length(bMsg));

Move(pad[0], msg[Length(bMsg)], Length(pad));

{$ENDREGION}

//aes.KeySize = 256; aes.BlockSize = 128; aes.Padding = PaddingMode.None; aes.Mode = CipherMode.CBC;

Move(aEncodingAESKeyBts[0], AesKey, Length(aEncodingAESKeyBts));

Move(IvBts[0], Iv, Length(IvBts));

InputStream := TMemoryStream.Create;

OutputStream := TMemoryStream.Create;

try

InputStream.Write(msg[0], Length(msg));

InputStream.Position := 0;

EncryptAESStreamCBC(InputStream, 0, AesKey, Iv, OutputStream);

Result := string(EncodeBase64(OutputStream.Memory, OutputStream.Size));

finally

InputStream.Free;

OutputStream.Free;

end;

function TWxMsgCrypt.CreateRandCode(codeLen: Integer): string;

var

codeSerial, code: string;

strLst: TStringList;

randValue, i: Integer;

begin

codeSerial := '2,3,4,5,6,7,a,c,d,e,f,h,i,j,k,m,n,p,r,s,t,A,C,D,E,F,G,H,J,K,M,N,P,Q,R,S,U,V,W,X,Y,Z';

if (codeLen = 0) then

codeLen := 16;

strLst := TStringList.Create;

try

ExtractStrings([','], [], PChar(codeSerial), strLst);

code := '';

Randomize;

for i := 0 to codeLen - 1 do

begin

randValue := Random(strLst.Count);

code := code + strLst[randValue];

end;

Result := code;

finally

strLst.Free;

end;

function TWxMsgCrypt.DecryptMsg(const sToken, sTimeStamp, sNonce, sMsgEncrypt, sSigture,

sAppID, sEncodingAESKey: string; var sMsg: string): WXBizMsgCryptErrorCode;

var

ret: WXBizMsgCryptErrorCode;

cpid: string;

function VerifySignature: WXBizMsgCryptErrorCode;

var

hash: string;

aStr: AnsiString;

AL: TStringList;

i: Integer;

begin

AL := TStringList.Create;

try

AL.Add(sToken);

AL.Add(sTimeStamp);

AL.Add(sNonce);

AL.Add(sMsgEncrypt);

AL.Sort;

hash := '';

for i := 0 to AL.Count - 1 do

hash := hash + AL[i];

aStr := AnsiString(hash);

hash := LowerCase(SHA1Print(SHA1StringA(aStr)));

finally

AL.Free;

end;

if (hash = sSigture) then

Result := WXBizMsgCrypt_OK

else

Result := WXBizMsgCrypt_ValidateSignature_Error;

end;

begin

sMsg := '';

if (Length(sEncodingAESKey) <> 43) then

begin

Result := WXBizMsgCryptErrorCode.WXBizMsgCrypt_IllegalAesKey;

Exit;

end;

//verify signature

ret := VerifySignature;

if (ret <> WXBizMsgCrypt_OK) then

begin

Result := ret;

Exit;

end;

//decrypt

cpid := '';

try

sMsg := AES_decrypt(sEncodingAESKey, sMsgEncrypt, cpid);

except

on E: Exception do

begin

if E.Message = '1' then

Result := WXBizMsgCrypt_DecodeBase64_Error

else

Result := WXBizMsgCrypt_DecryptAES_Error;

Exit;

end;

if (cpid <> sAppID) then

begin

Result := WXBizMsgCrypt_ValidateAppid_Error;

Exit;

end;

Result := WXBizMsgCrypt_OK;

end;

function TWxMsgCrypt.EncryptMsg(const sMsg, sToken, sAppID, sEncodingAESKey: string;

var sMsgEncrypt: string): WXBizMsgCryptErrorCode;

var

hash, wxDt, wxNonce, EncryptField: string;

function GenSignature: string;

var

hash: string;

aStr: AnsiString;

AL: TStringList;

i: Integer;

begin

AL := TStringList.Create;

try

AL.Add(sToken);

AL.Add(EncryptField);

wxDt := GetWxNowStr;

AL.Add(wxDt);

wxNonce := CreateRandCode(10);

AL.Add(wxNonce);

AL.Sort;

hash := '';

for i := 0 to AL.Count - 1 do

hash := hash + AL[i];

aStr := AnsiString(hash);

hash := LowerCase(SHA1Print(SHA1StringA(aStr)));

finally

AL.Free;

end;

Result := hash;

end;

begin

sMsgEncrypt := '';

if (Length(sEncodingAESKey) <> 43) then

begin

Result := WXBizMsgCryptErrorCode.WXBizMsgCrypt_IllegalAesKey;

Exit;

end;

//encrypt

try

EncryptField := AES_encrypt(sEncodingAESKey, sMsg, sAppID);

except

on E: Exception do

begin

if E.Message = '1' then

Result := WXBizMsgCrypt_DecryptAES_Error

else

Result := WXBizMsgCrypt_EncryptAES_Error;

Exit;

end;

//gen signature

try

hash := GenSignature;

except

Result := WXBizMsgCrypt_ComputeSignature_Error;

Exit;

end;

//xml

sMsgEncrypt := '' +

'' +

'';

Result := WXBizMsgCrypt_OK;

end;

end.

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