Using Crypto++ Library DES Alg

teppel (14)
Hi all,

I quite new to c++, my project require me use block cipher encryption. But i didn't know how to use the DES alg in crypto++ Library. Can anyone refer me to any tutorial or roughly show me how to start using the library class function ? Btw i using ubuntu as the platform to start the prj and g++ as the compiler. Because i cant google any tutorial that will explain step by step of the coding. I understand that this coding is not suitable for beginner like me, but i hope to get some knowledge out of it.

Installation of the package.
I follow as mention in the offical site,
1) > cd cryptopp/
> unzip -a cryptopp561.zip
2) > make
3) > cryptest.exe v (test result return OKAY)
4) > su -
Password:
# cd .../cryptopp-5.6.0/
# make install
==================================================
ERROR :
cp *.h /usr/include/cryptopp
cp *.a /usr/lib
cp *.so /usr/lib
cp: cannot stat `*.so': No such file or directory
make: *** [install] Error 1
===================================================
Is it alright to have cp: cannot stat `*.so': No such file or directory becuase i believe after extraction there no .so extension file.

My question now is how i start about doing encryption. As i believe that the above make install already copy all the header filer to the lib ? 

1
2
3
4
5
6
7
8
9
10
11
12
13
 
#include<cryptopp/des.h>
#include<iostream>

using namespace std;


int main(){
	
	Des a;// how should i call the encryption function


	return 0;
}


Somehow i got a gut feeling that i am going to make use of the below class, but i go about passing in the plaintext ? Do i need to set e key ? How about the padding for the last block ?

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
 
class DES : public DES_Info, public BlockCipherDocumentation
{
	class CRYPTOPP_NO_VTABLE Base : public BlockCipherImpl<DES_Info>, public RawDES
	{
	public:
		void UncheckedSetKey(const byte *userKey, unsigned int length, const NameValuePairs &params);
		void ProcessAndXorBlock(const byte *inBlock, const byte *xorBlock, byte *outBlock) const;
	};

public:
	//! check DES key parity bits
	static bool CheckKeyParityBits(const byte *key);
	//! correct DES key parity bits
	static void CorrectKeyParityBits(byte *key);

	typedef BlockCipherFinal<ENCRYPTION, Base> Encryption; 
	typedef BlockCipherFinal<DECRYPTION, Base> Decryption;
};


[/code]

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
 
#ifndef CRYPTOPP_DES_H
#define CRYPTOPP_DES_H

/** \file
*/

#include "seckey.h"
#include "secblock.h"

NAMESPACE_BEGIN(CryptoPP)

class CRYPTOPP_DLL RawDES
{
public:
	void RawSetKey(CipherDir direction, const byte *userKey);
	void RawProcessBlock(word32 &l, word32 &r) const;

protected:
	static const word32 Spbox[8][64];

	FixedSizeSecBlock<word32, 32> k;
};

//! _
struct DES_Info : public FixedBlockSize<8>, public FixedKeyLength<8>
{
	// disable DES in DLL version by not exporting this function
	static const char * StaticAlgorithmName() {return "DES";}
};

/// <a href="http://www.weidai.com/scan-mirror/cs.html#DES">DES</a>
/*! The DES implementation in Crypto++ ignores the parity bits
	(the least significant bits of each byte) in the key. However
	you can use CheckKeyParityBits() and CorrectKeyParityBits() to
	check or correct the parity bits if you wish. */
class DES : public DES_Info, public BlockCipherDocumentation
{
	class CRYPTOPP_NO_VTABLE Base : public BlockCipherImpl<DES_Info>, public RawDES
	{
	public:
		void UncheckedSetKey(const byte *userKey, unsigned int length, const NameValuePairs &params);
		void ProcessAndXorBlock(const byte *inBlock, const byte *xorBlock, byte *outBlock) const;
	};

public:
	//! check DES key parity bits
	static bool CheckKeyParityBits(const byte *key);
	//! correct DES key parity bits
	static void CorrectKeyParityBits(byte *key);

	typedef BlockCipherFinal<ENCRYPTION, Base> Encryption;
	typedef BlockCipherFinal<DECRYPTION, Base> Decryption;
};

//! _
struct DES_EDE2_Info : public FixedBlockSize<8>, public FixedKeyLength<16>
{
	CRYPTOPP_DLL static const char * CRYPTOPP_API StaticAlgorithmName() {return "DES-EDE2";}
};

/// <a href="http://www.weidai.com/scan-mirror/cs.html#DESede">DES-EDE2</a>
class DES_EDE2 : public DES_EDE2_Info, public BlockCipherDocumentation
{
	class CRYPTOPP_DLL CRYPTOPP_NO_VTABLE Base : public BlockCipherImpl<DES_EDE2_Info>
	{
	public:
		void UncheckedSetKey(const byte *userKey, unsigned int length, const NameValuePairs &params);
		void ProcessAndXorBlock(const byte *inBlock, const byte *xorBlock, byte *outBlock) const;

	protected:
		RawDES m_des1, m_des2;
	};

public:
	typedef BlockCipherFinal<ENCRYPTION, Base> Encryption;
	typedef BlockCipherFinal<DECRYPTION, Base> Decryption;
};

//! _
struct DES_EDE3_Info : public FixedBlockSize<8>, public FixedKeyLength<24>
{
	CRYPTOPP_DLL static const char * CRYPTOPP_API StaticAlgorithmName() {return "DES-EDE3";}
};

/// <a href="http://www.weidai.com/scan-mirror/cs.html#DESede">DES-EDE3</a>
class DES_EDE3 : public DES_EDE3_Info, public BlockCipherDocumentation
{
	class CRYPTOPP_DLL CRYPTOPP_NO_VTABLE Base : public BlockCipherImpl<DES_EDE3_Info>
	{
	public:
		void UncheckedSetKey(const byte *userKey, unsigned int length, const NameValuePairs &params);
		void ProcessAndXorBlock(const byte *inBlock, const byte *xorBlock, byte *outBlock) const;

	protected:
		RawDES m_des1, m_des2, m_des3;
	};

public:
	typedef BlockCipherFinal<ENCRYPTION, Base> Encryption;
	typedef BlockCipherFinal<DECRYPTION, Base> Decryption;
};

//! _
struct DES_XEX3_Info : public FixedBlockSize<8>, public FixedKeyLength<24>
{
	static const char *StaticAlgorithmName() {return "DES-XEX3";}
};

/// <a href="http://www.weidai.com/scan-mirror/cs.html#DESX">DES-XEX3</a>, AKA DESX
class DES_XEX3 : public DES_XEX3_Info, public BlockCipherDocumentation
{
	class CRYPTOPP_NO_VTABLE Base : public BlockCipherImpl<DES_XEX3_Info>
	{
	public:
		void UncheckedSetKey(const byte *userKey, unsigned int length, const NameValuePairs &params);
		void ProcessAndXorBlock(const byte *inBlock, const byte *xorBlock, byte *outBlock) const;

	protected:
		FixedSizeSecBlock<byte, BLOCKSIZE> m_x1, m_x3;
		// VS2005 workaround: calling modules compiled with /clr gets unresolved external symbol DES::Base::ProcessAndXorBlock
		// if we use DES::Encryption here directly without value_ptr.
		value_ptr<DES::Encryption> m_des;
	};

public:
	typedef BlockCipherFinal<ENCRYPTION, Base> Encryption;
	typedef BlockCipherFinal<DECRYPTION, Base> Decryption;
};

typedef DES::Encryption DESEncryption;
typedef DES::Decryption DESDecryption;

typedef DES_EDE2::Encryption DES_EDE2_Encryption;
typedef DES_EDE2::Decryption DES_EDE2_Decryption;

typedef DES_EDE3::Encryption DES_EDE3_Encryption;
typedef DES_EDE3::Decryption DES_EDE3_Decryption;

typedef DES_XEX3::Encryption DES_XEX3_Encryption;
typedef DES_XEX3::Decryption DES_XEX3_Decryption;

NAMESPACE_END

#endif


Last edited on
kooth (746)
Buy yourself a copy of "Network Security with OpenSSL" from O'Reilly books. It is the best resource I've found for this subject.
Topic archived. No new replies allowed.