Шифрование

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Serg7077 (2003-12-16 15:02) [0]

Где нибудь есть исходные тексты по реализации алгоритма шифрования с открытым ключом ? Дайте ссылочку пожулуйста )))

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Reindeer Moss Eater (2003-12-16 15:31) [1]

Алгоритма шифрования с открытым ключем нет.

Есть системы криптозащиты с открытыми ключами.
Они внутри себя используют самые обычные блочные и потоковые алгоритмы шифров на симметричных секретных ключах.

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Digitman (2003-12-16 18:13) [2]

только в кач-ве иллюстрации к широкоизвестному ICQ-алгоритму шифрования, адаптированному к некоторым элементам MIDAS-технологии :

const DataBlockHdrSize = 12; // Signature(DWord) + Context(DWord) + DataSize(DWord) type ... { TACSDataCodec } const { таблица констант, испольуемых для шифрации пакетов по умолчанию } DefaultCryptTable: TCryptTable = ( $59, $60, $37, $6B, $65, $62, $46, $48, $53, $61, $4C, $59, $60, $57, $5B, $3D, $5E, $34, $6D, $36, $50, $3F, $6F, $67, $53, $61, $4C, $59, $40, $47, $63, $39, $50, $5F, $5F, $3F, $6F, $47, $43, $69, $48, $33, $31, $64, $35, $5A, $4A, $42, $56, $40, $67, $53, $41, $07, $6C, $49, $58, $3B, $4D, $46, $68, $43, $69, $48, $33, $31, $44, $65, $62, $46, $48, $53, $41, $07, $6C, $69, $48, $33, $51, $54, $5D, $4E, $6C, $49, $38, $4B, $55, $4A, $62, $46, $48, $33, $51, $34, $6D, $36, $50, $5F, $5F, $5F, $3F, $6F, $47, $63, $59, $40, $67, $33, $31, $64, $35, $5A, $6A, $52, $6E, $3C, $51, $34, $6D, $36, $50, $5F, $5F, $3F, $4F, $37, $4B, $35, $5A, $4A, $62, $66, $58, $3B, $4D, $66, $58, $5B, $5D, $4E, $6C, $49, $58, $3B, $4D, $66, $58, $3B, $4D, $46, $48, $53, $61, $4C, $59, $40, $67, $33, $31, $64, $55, $6A, $32, $3E, $44, $45, $52, $6E, $3C, $31, $64, $55, $6A, $52, $4E, $6C, $69, $48, $53, $61, $4C, $39, $30, $6F, $47, $63, $59, $60, $57, $5B, $3D, $3E, $64, $35, $3A, $3A, $5A, $6A, $52, $4E, $6C, $69, $48, $53, $61, $6C, $49, $58, $3B, $4D, $46, $68, $63, $39, $50, $5F, $5F, $3F, $6F, $67, $53, $41, $25, $41, $3C, $51, $54, $3D, $5E, $54, $5D, $4E, $4C, $39, $50, $5F, $5F, $5F, $3F, $6F, $47, $43, $69, $48, $33, $51, $54, $5D, $6E, $3C, $31, $64, $35, $5A, $00, $00 ); { константа, используемая в качестве ключа шифрования по умолчанию } DefaultCryptKey = $6A6C6865; type TACSDataCodec = class(TInterfacedObject, IDataCodec) private FCryptTable: PCryptTable; FCryptKey: TCryptKey; FInStream: TMemoryStream; FOutStream: TMemoryStream; FEnabled: Boolean; protected function Get_Enabled: WordBool; stdcall; procedure Set_Enabled(const Value: WordBool); stdcall; function Get_CryptKey: TCryptKey; stdcall; procedure Set_CryptKey(const Value: TCryptKey); stdcall; function Get_CryptTable: PCryptTable; stdcall; procedure Set_CryptTable(Value: PCryptTable); stdcall; procedure EncryptData(const Data: IDataBlock); virtual; stdcall; procedure DecryptData(const Data: IDataBlock); virtual; stdcall; procedure RandomizeCryptTable; virtual; stdcall; public constructor Create; overload; constructor Create(ACryptTable: PCryptTable; const ACryptKey: TCryptKey = DefaultCryptKey); overload; destructor Destroy; override; end; ... implementation ... { TACSDataCodec } constructor TACSDataCodec.Create; begin inherited Create; FCryptKey:= DefaultCryptKey; FCryptTable:= @DefaultCryptTable; FEnabled:= True; end; constructor TACSDataCodec.Create(ACryptTable: PCryptTable; const ACryptKey: TCryptKey); begin inherited Create; if Assigned(ACryptTable) and (ACryptTable <> @DefaultCryptTable) then Set_CryptTable(ACryptTable) else FCryptTable:= @DefaultCryptTable; FCryptKey:= ACryptKey; FEnabled:= True; end; destructor TACSDataCodec.Destroy; begin if FCryptTable <> @DefaultCryptTable then FreeMem(FCryptTable); inherited Destroy; end; function TACSDataCodec.Get_Enabled: WordBool; begin Result:= FEnabled; end; procedure TACSDataCodec.Set_Enabled(const Value: WordBool); begin FEnabled:= Value; end; procedure TACSDataCodec.DecryptData(const Data: IDataBlock); var i, x, k, FullPacketSize, DataPacketSize, CheckCode, EncryptCode: DWORD; Packet: PByteArray; begin if Assigned(Data) and (Data.Size > 0) and FEnabled then with Data do begin Packet:= PByteArray(Integer(Memory) + BytesReserved); FullPacketSize:= Stream.Size; DataPacketSize:= FullPacketSize - BytesReserved - SizeOf(CheckCode); CheckCode:= PInteger(@Packet[DataPacketSize])^; CheckCode:= ((CheckCode and $0001F000) shr $0C) or ((CheckCode and $07C007C0) shr $01) or ((CheckCode and $003E0001) shl $0A) or ((CheckCode and $F8000000) shr $10) or ((CheckCode and $0000083E) shl $0F); EncryptCode:= FullPacketSize * FCryptKey + CheckCode; i:= 0; while i < DataPacketSize do begin k:= Min(DataPacketSize - i, SizeOf(DWORD)); Move(Packet[i], x, k); x:= x xor (EncryptCode + FCryptTable[i and $FF]); Move(x, Packet[i], k); Inc(i, k); end; Size:= DataPacketSize; end; end; procedure TACSDataCodec.EncryptData(const Data: IDataBlock); var i, x, z, k, R1, R2, N1, N2, N3, HeaderSize, FullPacketSize, DataPacketSize, CheckCode, EncryptCode: DWORD; Packet: PByteArray; begin if Assigned(Data) and (Data.Size > 0) and FEnabled then with Data do begin HeaderSize:= BytesReserved; Write(CheckCode, SizeOf(CheckCode)); FullPacketSize:= Stream.Size; DataPacketSize:= FullPacketSize - HeaderSize - SizeOf(CheckCode); Packet:= PByteArray(Memory); i:= (Packet[1] shl 24) or (Packet[4] shl 16) or (Packet[0] shl 8) or Packet[5]; x:= HeaderSize + Random(FullPacketSize - HeaderSize); z:= Random(SizeOf(TCryptTable)); k:= ((x shl 24) or (Packet[x] shl 16) or (z shl 8) or Packet[z]) xor $00FF00FF; CheckCode:= i xor k; EncryptCode:= FullPacketSize * FCryptKey + CheckCode; Packet:= PByteArray(Integer(Packet) + HeaderSize); i:= 0; while i < DataPacketSize do begin k:= Min(DataPacketSize - i, SizeOf(DWORD)); Move(Packet[i], x, k); x:= x xor (EncryptCode + FCryptTable[i and $FF]); Move(x, Packet[i], k); Inc(i, k); end; PInteger(@Packet[i])^:= ((CheckCode and $0000001F) shl $0C) or ((CheckCode and $03E003E0) shl $01) or ((CheckCode and $F8000400) shr $0A) or ((CheckCode and $0000F800) shl $10) or ((CheckCode and $041F0000) shr $0F); end; end; function TACSDataCodec.Get_CryptKey: TCryptKey; begin Result:= FCryptKey; end; procedure TACSDataCodec.Set_CryptKey(const Value: TCryptKey); begin FCryptKey:= Value; end; function TACSDataCodec.Get_CryptTable: PCryptTable; begin Result:= FCryptTable; end; procedure TACSDataCodec.Set_CryptTable(Value: PCryptTable); var TempCryptTable: PCryptTable; begin GetMem(TempCryptTable, SizeOf(TCryptTable)); try Move(Value^, TempCryptTable^, SizeOf(TCryptTable)); if FCryptTable <> @DefaultCryptTable then FreeMem(FCryptTable); FCryptTable:= TempCryptTable; except FreeMem(TempCryptTable); raise; end; end; procedure TACSDataCodec.RandomizeCryptTable; var rn: Integer; RTable: PCryptTable; begin Randomize; rn:= 1 + Random(SizeOf(TCryptTable) - 2); GetMem(RTable, SizeOf(TCryptTable)); FillChar(RTable^, SizeOf(TCryptTable), 0); try Move(DefaultCryptTable[rn], RTable^, SizeOf(TCryptTable) - rn); Move(DefaultCryptTable, RTable[SizeOf(TCryptTable) - rn], rn); if FCryptTable <> @DefaultCryptTable then FreeMem(FCryptTable); FCryptTable:= RTable; except FreeMem(RTable); raise; end; end; ... end.

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