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Added first helper routine for ZIP support
Added a new unit along with unit tests to create DEC instances for implementing support for encrypting/decrypting ZIP files.
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‎Source/DEC60.dpr‎

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Original file line numberDiff line numberDiff line change
@@ -45,7 +45,8 @@ uses
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DECUtilRawByteStringHelper in 'DECUtilRawByteStringHelper.pas',
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DECHashAuthentication in 'DECHashAuthentication.pas',
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DECHashBitBase in 'DECHashBitBase.pas',
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DECCipherModesGCM in 'DECCipherModesGCM.pas';
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DECCipherModesGCM in 'DECCipherModesGCM.pas',
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DECZIPHelper in 'DECZIPHelper.pas';
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begin
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try

‎Source/DECZIPHelper.pas‎

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@@ -0,0 +1,90 @@
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{*****************************************************************************
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The DEC team (see file NOTICE.txt) licenses this file
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to you under the Apache License, Version 2.0 (the
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"License"); you may not use this file except in compliance
5+
with the License. A copy of this licence is found in the root directory of
6+
this project in the file LICENCE.txt or alternatively at
7+
8+
http://www.apache.org/licenses/LICENSE-2.0
9+
10+
Unless required by applicable law or agreed to in writing,
11+
software distributed under the License is distributed on an
12+
"AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
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KIND, either express or implied. See the License for the
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specific language governing permissions and limitations
15+
under the License.
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*****************************************************************************}
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/// <summary>
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/// Routines etc. for use with encrypted ZIP files
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/// </summary>
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unit DECZIPHelper;
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interface
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uses
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DECCiphers,
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DECCipherFormats;
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/// <summary>
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/// Creates an instance for encrypting or decrypting the algorithm specified
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/// by the ZIP Algorithm ID documented in chapter 7.2.3.2 found in
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/// https://pkware.cachefly.net/webdocs/casestudies/APPNOTE.TXT
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/// </summary>
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/// <param name="AlgorithmID">
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/// Unique ID for a crypto algorithm as specified in the documentation
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/// </param>
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/// <returns>
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/// Created instance of the cipher class
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/// </returns>
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/// <exception cref="EDECClassNotRegisteredException">
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/// Exception raised if called with an unknown/unsupported AlgorithmID
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/// </exception>
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function CreateZIPCryptoAlgorithmInstance(AlgorithmID: UInt16):TDECFormattedCipher;
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resourcestring
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/// <summary>
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/// Exception text for attempts to create an instance for an unknown
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/// algorithm ID
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/// </summary>
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rUnknownZIPAlgorithmID = 'Unknown ZIP cypher algorithm ID %0:d';
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implementation
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uses
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System.SysUtils,
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DECTypes,
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DECCipherBase;
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function CreateZIPCryptoAlgorithmInstance(AlgorithmID: UInt16):TDECFormattedCipher;
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begin
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Result := nil;
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case AlgorithmID of
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$6601 : Result := TCipher_1DES.Create;
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// $6602 : Result := TCipher_RC2.Create; // (version needed to extract < 5.2)
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// // This has to do with a faulty RC2
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// // implementation in XP SP1 and earlier
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// // Unsupported as we do not know the
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// // details of the fault
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$6603 : Result := TCipher_3DES.Create; // 3DES 168
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$6609 : Result := TCipher_2DES.Create; // 3DES 112
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$660E : Result := TCipher_AES128.Create;
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$660F : Result := TCipher_AES192.Create;
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$6610 : Result := TCipher_AES256.Create;
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$6702 : Result := TCipher_RC2.Create; // (version needed to extract >= 5.2)
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$6720 : Result := TCipher_Blowfish.Create;
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$6721 : Result := TCipher_Twofish.Create;
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$6801 : Result := TCipher_RC4.Create;
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$FFFF : raise EDECClassNotRegisteredException.Create(Format(rUnknownZIPAlgorithmID,
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[AlgorithmID]));
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else
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raise EDECClassNotRegisteredException.Create(Format(rUnknownZIPAlgorithmID,
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[AlgorithmID]));
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end;
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if Assigned(Result) then
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Result.Mode := cmCBCx;
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end;
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end.

‎Unit Tests/DECDUnitTestSuite.dpr‎

Lines changed: 2 additions & 3 deletions
Original file line numberDiff line numberDiff line change
@@ -16,11 +16,9 @@ program DECDUnitTestSuite;
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{$ENDIF}
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uses
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// FastMM4,
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Vcl.Forms,
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{$IFDEF TESTINSIGHT}
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TestInsight.Client,
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TestInsight.DUnit,
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{$ELSE}
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TestFramework,
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GUITestRunner,
@@ -40,7 +38,8 @@ uses
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TestDECCipherFormats in 'Tests\TestDECCipherFormats.pas',
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TestDECHashMAC in 'Tests\TestDECHashMAC.pas',
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TestDECHashSHA3 in 'Tests\TestDECHashSHA3.pas',
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TestDECCipherModesGCM in 'Tests\TestDECCipherModesGCM.pas';
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TestDECCipherModesGCM in 'Tests\TestDECCipherModesGCM.pas',
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TestDECZIPHelper in 'Tests\TestDECZIPHelper.pas';
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{$R *.RES}
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‎Unit Tests/Tests/TestDECZIPHelper.pas‎

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Original file line numberDiff line numberDiff line change
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{*****************************************************************************
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The DEC team (see file NOTICE.txt) licenses this file
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to you under the Apache License, Version 2.0 (the
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"License"); you may not use this file except in compliance
5+
with the License. A copy of this licence is found in the root directory of
6+
this project in the file LICENCE.txt or alternatively at
7+
8+
http://www.apache.org/licenses/LICENSE-2.0
9+
10+
Unless required by applicable law or agreed to in writing,
11+
software distributed under the License is distributed on an
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"AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
13+
KIND, either express or implied. See the License for the
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specific language governing permissions and limitations
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under the License.
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*****************************************************************************}
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{$M+} // DUnitX would add it anyway
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unit TestDECZIPHelper;
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interface
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// Needs to be included before any other statements
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{$INCLUDE TestDefines.inc}
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uses
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System.SysUtils, System.Classes,
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{$IFDEF DUnitX}
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DUnitX.TestFramework,DUnitX.DUnitCompatibility,
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{$ELSE}
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TestFramework,
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{$ENDIF}
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DECUtil;
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type
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/// <summary>
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/// Test cases for the various helper functions
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/// </summary>
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TestZIPHelpers = class(TTestCase)
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strict private
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/// <summary>
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/// Perform a signle algorithm create test
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/// </summary>
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/// <param name="AlgorithmID">
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/// ID of the algorithm instance to create
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/// </param>
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/// <param name="Name">
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/// Short class name of the instance to be created, must match to pass
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/// </param>
50+
procedure DoTestCreateZIPCryptoAlgorithmInstance(AlgorithmID: UInt16;
51+
const Name : string);
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/// <summary>
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/// Test for the "unknown" algorithm ID as parameter
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/// </summary>
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procedure DoTestCreateZIPUnknownCryptoAlgorithmException;
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/// <summary>
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/// Test for an arbitrary unknown algorithm ID as parameter
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/// </summary>
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procedure DoTestCreateZIPUnknCryptoAlgorithmException;
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published
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procedure TestCreateZIPCryptoAlgorithmInstance;
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procedure TestCreateZIPUnknownCryptoAlgorithmInstanceException;
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procedure TestCreateZIPUnknCryptoAlgorithmInstanceException;
64+
end;
65+
66+
implementation
67+
68+
uses
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DECTypes,
70+
DECCipherFormats,
71+
DECZIPHelper;
72+
73+
procedure TestZIPHelpers.DoTestCreateZIPUnknCryptoAlgorithmException;
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var
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Instance : TDECFormattedCipher;
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begin
77+
Instance := CreateZIPCryptoAlgorithmInstance($1000);
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Instance.Free; // Should not be reached but suppresses compiler warning
79+
end;
80+
81+
procedure TestZIPHelpers.DoTestCreateZIPUnknownCryptoAlgorithmException;
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var
83+
Instance : TDECFormattedCipher;
84+
begin
85+
Instance := CreateZIPCryptoAlgorithmInstance($FFFF);
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Instance.Free; // Should not be reached but suppresses compiler warning
87+
end;
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89+
procedure TestZIPHelpers.DoTestCreateZIPCryptoAlgorithmInstance(AlgorithmID: UInt16;
90+
const Name: string);
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var
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Instance : TDECFormattedCipher;
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begin
94+
Instance := CreateZIPCryptoAlgorithmInstance(AlgorithmID);
95+
try
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CheckEquals(Name, Instance.GetShortClassName);
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finally
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Instance.Free;
99+
end;
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end;
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102+
procedure TestZIPHelpers.TestCreateZIPCryptoAlgorithmInstance;
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begin
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DoTestCreateZIPCryptoAlgorithmInstance($6601, '1DES');
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DoTestCreateZIPCryptoAlgorithmInstance($6603, '3DES');
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DoTestCreateZIPCryptoAlgorithmInstance($6609, '2DES');
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DoTestCreateZIPCryptoAlgorithmInstance($660E, 'AES128');
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DoTestCreateZIPCryptoAlgorithmInstance($660F, 'AES192');
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DoTestCreateZIPCryptoAlgorithmInstance($6610, 'AES256');
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DoTestCreateZIPCryptoAlgorithmInstance($6702, 'RC2');
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DoTestCreateZIPCryptoAlgorithmInstance($6720, 'Blowfish');
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DoTestCreateZIPCryptoAlgorithmInstance($6721, 'Twofish');
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DoTestCreateZIPCryptoAlgorithmInstance($6801, 'RC4');
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// $6602 : Result := TCipher_RC2.Create; // (version needed to extract < 5.2)
116+
// // This has to do with a faulty RC2
117+
// // implementation in XP SP1 and earlier
118+
// // Unsupported as we do not know the
119+
// // details of the fault
120+
end;
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procedure TestZIPHelpers.TestCreateZIPUnknCryptoAlgorithmInstanceException;
123+
begin
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CheckException(DoTestCreateZIPUnknCryptoAlgorithmException, EDECClassNotRegisteredException);
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end;
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procedure TestZIPHelpers.TestCreateZIPUnknownCryptoAlgorithmInstanceException;
128+
begin
129+
CheckException(DoTestCreateZIPUnknownCryptoAlgorithmException, EDECClassNotRegisteredException);
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end;
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initialization
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// Register any test cases with the test runner
134+
{$IFDEF DUnitX}
135+
TDUnitX.RegisterTestFixture(TestZIPHelpers);
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{$ELSE}
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RegisterTest('DECZIPHelper', TestZIPHelpers.Suite);
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{$ENDIF}
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end.

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