忙活了一周，基本完成了Crypto++库中关于RSA加解密的API封装！这一周里，查了很多Crypto++的相关资料，感觉这方面的内容乏善可陈，或者太简单，或者太笼统！本文希望能给使用Crypto++的朋友带来一些帮助，主要还是源代码了，实在没有时间码文字！在测试过程中，感觉Crypto++还是非常高效的，期待更多的人使用Crypto++。此外，Crypto++的源代码极富研究价值，是深入学习C++的经典材料！爱好 C++的你，千万别错过了~

本文提供的C++源代码已在Redhat Enterprise Server 5.0和Windows XP平台编译链接成功，使用的编译器分别是g++ 3.4.6、Visual C++ 6.0 (SP 6)。由于两个平台的代码差别不大，仅提供Linux平台的代码！如果你需要Windows平台的代码，可以向我索取，留下你的邮件地址即可！如果你在使用过程中，遇到任何问题，也欢迎你给我留言！

源程序主要包括五个文件：MyRSA.h、 MyRSA.cpp、Main.h、Main.cpp、makefile；两个目录：lib目录包含libcryptopp.a，include目录包含Crypto++5.5.2中的所有.h头文件。对了，上述五个文件与lib,include目录在同一层目录！需要说明的是，makefile是借用了一个兄弟的，忘记名字了，不好意思:-)

哈，还是贴代码吧!

/************************** MyRSA.h ********************************/ #ifndef __MYRSA_H__ #define __MYRSA_H__ #include <string> #include "files.h" #include "filters.h" #include "hex.h" #include "randpool.h" #include "rsa.h" using namespace std; using namespace CryptoPP; class CMyRSA { public: CMyRSA(void); virtual ~CMyRSA(void); //You must set the KeyLength 512, 1024, 2048 ... void GenerateKey(const unsigned int KeyLength, const char *Seed, RSAES_OAEP_SHA_Decryptor &Priv, RSAES_OAEP_SHA_Encryptor &Pub); void GenerateKey(const unsigned int KeyLength, const char *Seed, string &strPriv, string &strPub); //use public key to encrypt void EncryptString(const RSAES_OAEP_SHA_Encryptor &Pub, const char *Seed, const string &Plaintext, string &Ciphertext); void EncryptString(const string &strPub, const char *Seed, const string &Plaintext, string &Ciphertext); //use private key to decrypt void DecryptString(const RSAES_OAEP_SHA_Decryptor &Priv, const string &Ciphertext, string &Plaintext); void DecryptString(const string &strPriv, const string &Ciphertext, string &Plaintext); private: static RandomPool & RNG(void); private: static RandomPool m_sRandPool; }; #endif /* End of __MYRSA_H__ */ /************************** MyRSA.cpp ********************************/ #include "MyRSA.h" CMyRSA::CMyRSA() { } CMyRSA::~CMyRSA(void) { } void CMyRSA::GenerateKey(const unsigned int KeyLength, const char *Seed, RSAES_OAEP_SHA_Decryptor &Priv, RSAES_OAEP_SHA_Encryptor &Pub) { RandomPool RandPool; RandPool.IncorporateEntropy((byte *)Seed, strlen(Seed)); //generate private key Priv = RSAES_OAEP_SHA_Decryptor(RandPool, KeyLength); //generate public key using private key Pub = RSAES_OAEP_SHA_Encryptor(Priv); } void CMyRSA::GenerateKey(const unsigned int KeyLength, const char *Seed, string &strPriv, string &strPub) { RandomPool RandPool; RandPool.IncorporateEntropy((byte *)Seed, strlen(Seed)); //generate private key RSAES_OAEP_SHA_Decryptor Priv(RandPool, KeyLength); HexEncoder PrivateEncoder(new StringSink(strPriv));//本博客作者加：就为了这句代码整整找了1天！ Priv.DEREncode(PrivateEncoder); PrivateEncoder.MessageEnd(); //generate public key using private key RSAES_OAEP_SHA_Encryptor Pub(Priv); HexEncoder PublicEncoder(new StringSink(strPub)); Pub.DEREncode(PublicEncoder); PublicEncoder.MessageEnd(); } void CMyRSA::EncryptString(const RSAES_OAEP_SHA_Encryptor &Pub, const char *Seed, const string &Plaintext, string &Ciphertext) { RandomPool RandPool; RandPool.IncorporateEntropy((byte *)Seed, strlen(Seed)); int MaxMsgLength = Pub.FixedMaxPlaintextLength(); for (int i = Plaintext.size(), j=0; i > 0; i -= MaxMsgLength, j += MaxMsgLength) { string PartPlaintext = Plaintext.substr(j, MaxMsgLength); string PartCiphertext; StringSource(PartPlaintext, true, new PK_EncryptorFilter(RandPool, Pub, new HexEncoder(new StringSink(PartCiphertext)))); Ciphertext += PartCiphertext; } } void CMyRSA::EncryptString(const string &strPub, const char *Seed, const string &Plaintext, string &Ciphertext) { StringSource PublicKey(strPub, true, new HexDecoder); RSAES_OAEP_SHA_Encryptor Pub(PublicKey); RandomPool RandPool; RandPool.IncorporateEntropy((byte *)Seed, strlen(Seed)); int MaxMsgLength = Pub.FixedMaxPlaintextLength(); for (int i = Plaintext.size(), j=0; i > 0; i -= MaxMsgLength, j += MaxMsgLength) { string PartPlaintext = Plaintext.substr(j, MaxMsgLength); string PartCiphertext; StringSource(PartPlaintext, true, new PK_EncryptorFilter(RandPool, Pub, new HexEncoder(new StringSink(PartCiphertext)))); Ciphertext += PartCiphertext; } } void CMyRSA::DecryptString(const RSAES_OAEP_SHA_Decryptor &Priv, const string &Ciphertext, string &Plaintext) { //indicate the ciphertext in hexcode int CiphertextLength = Priv.FixedCiphertextLength() * 2; for (int i = Ciphertext.size(), j=0; i > 0; i -= CiphertextLength, j += CiphertextLength) { string PartCiphertext = Ciphertext.substr(j, CiphertextLength); string PartPlaintext; StringSource(PartCiphertext, true, new HexDecoder(new PK_DecryptorFilter(RNG(), Priv, new StringSink(PartPlaintext)))); Plaintext += PartPlaintext; } } void CMyRSA::DecryptString(const string &strPriv, const string &Ciphertext, string &Plaintext) { StringSource PrivKey(strPriv, true, new HexDecoder); RSAES_OAEP_SHA_Decryptor Priv(PrivKey); //indicate the ciphertext in hexcode int CiphertextLength = Priv.FixedCiphertextLength() * 2; for (int i = Ciphertext.size(), j=0; i > 0; i -= CiphertextLength, j += CiphertextLength) { string PartCiphertext = Ciphertext.substr(j, CiphertextLength); string PartPlaintext; StringSource(PartCiphertext, true, new HexDecoder(new PK_DecryptorFilter(RNG(), Priv, new StringSink(PartPlaintext)))); Plaintext += PartPlaintext; } } RandomPool & CMyRSA::RNG(void) { return m_sRandPool; } RandomPool CMyRSA::m_sRandPool; /************************** Main.h ********************************/ #ifndef __MAIN_H__ #define __MAIN_H__ #endif /* End of __MAIN_H__ */ /************************** Main.cpp ********************************/ #include <unistd.h> #include <iostream> #include "Main.h" #include "MyRSA.h" /***** STATIC VARIABLES *****/ static RSAES_OAEP_SHA_Encryptor g_Pub; static RSAES_OAEP_SHA_Decryptor g_Priv; static string g_strPub; static string g_strPriv; int main(int argc, char *argv[]) { try { char Seed[1024], Message[1024], MessageSeed[1024]; unsigned int KeyLength; CMyRSA MyRSA; cout << "Key length in bits: "; cin >> KeyLength; cout << "/nRandom Seed: "; ws(cin); cin.getline(Seed, 1024); cout << "/nMessage: "; ws(cin); cin.getline(Message, 1024); cout << "/nRandom Message Seed: "; ws(cin); cin.getline(MessageSeed, 1024); MyRSA.GenerateKey(KeyLength, Seed, g_Priv, g_Pub); //MyRSA.GenerateKey(KeyLength, Seed, g_strPriv, g_strPub); //If generate key in RSAES_OAEP_SHA_Encryptor and RSAES_OAEP_SHA_Decryptor, please note four lines below /* cout << "g_strPub = " << g_strPub << endl; cout << endl; cout << "g_strPriv = " << g_strPriv << endl; cout << endl; */ string Plaintext(Message); string Ciphertext; MyRSA.EncryptString(g_Pub, MessageSeed, Plaintext, Ciphertext); //MyRSA.EncryptString(g_strPub, MessageSeed, Plaintext, Ciphertext); cout << "/nCiphertext: " << Ciphertext << endl; cout << endl; string Decrypted; MyRSA.DecryptString(g_Priv, Ciphertext, Decrypted); //MyRSA.DecryptString(g_strPriv, Ciphertext, Decrypted); cout << "/nDecrypted: " << Decrypted << endl; return 0; } catch(CryptoPP::Exception const &e) { cout << "/nCryptoPP::Exception caught: " << e.what() << endl; return -1; } catch(std::exception const &e) { cout << "/nstd::exception caught: " << e.what() << endl; return -2; } return -3; } /************************** Makefile ********************************/ # The executable file name. PROGRAM := myrsa # The directories in which source files reside. SRCDIRS := . # current directory # The source file types (headers excluded). SRCEXTS := .cpp # The flags used by the cpp (man cpp for more). CPPFLAGS := # The compiling flags used only for C. # If it is a C++ program, no need to set these flags. # If it is a C and C++ merging program, set these flags for the C parts. CFLAGS := CFLAGS += # The compiling flags used only for C++. # If it is a C program, no need to set these flags. # If it is a C and C++ merging program, set these flags for the C++ parts. CXXFLAGS := -g -O2 -I./include CXXFLAGS += # The library and the link options ( C and C++ common). LDFLAGS := -L./lib -lcryptopp LDFLAGS += ## Implict Section: change the following only when necessary. ##============================================================================= # The C program compiler. Uncomment it to specify yours explicitly. #CC = gcc # The C++ program compiler. Uncomment it to specify yours explicitly. CXX = g++ # Uncomment the 2 lines to compile C programs as C++ ones. CC = $(CXX) CFLAGS = $(CXXFLAGS) # The command used to delete file. RM = rm -f ## Stable Section: usually no need to be changed. But you can add more. ##============================================================================= SHELL = /bin/sh SOURCES = $(foreach d,$(SRCDIRS),$(wildcard $(addprefix $(d)/*,$(SRCEXTS)))) OBJS = $(foreach x,$(SRCEXTS), / $(patsubst %$(x),%.o,$(filter %$(x),$(SOURCES)))) DEPS = $(patsubst %.o,%.d,$(OBJS)) .PHONY : all objs clean cleanall rebuild all : $(PROGRAM) # Rules for creating the dependency files (.d). #--------------------------------------------------- %.d : %.c @$(CC) -MM -MD $(CFLAGS) $< %.d : %.C @$(CC) -MM -MD $(CXXFLAGS) $< %.d : %.cc @$(CC) -MM -MD $(CXXFLAGS) $< %.d : %.cpp @$(CC) -MM -MD $(CXXFLAGS) $< %.d : %.CPP @$(CC) -MM -MD $(CXXFLAGS) $< %.d : %.c++ @$(CC) -MM -MD $(CXXFLAGS) $< %.d : %.cp @$(CC) -MM -MD $(CXXFLAGS) $< %.d : %.cxx @$(CC) -MM -MD $(CXXFLAGS) $< # Rules for producing the objects. #--------------------------------------------------- objs : $(OBJS) %.o : %.c $(CC) -c $(CPPFLAGS) $(CFLAGS) $< %.o : %.C $(CXX) -c $(CPPFLAGS) $(CXXFLAGS) $< %.o : %.cc $(CXX) -c $(CPPFLAGS) $(CXXFLAGS) $< %.o : %.cpp $(CXX) -c $(CPPFLAGS) $(CXXFLAGS) $< %.o : %.CPP $(CXX) -c $(CPPFLAGS) $(CXXFLAGS) $< %.o : %.c++ $(CXX -c $(CPPFLAGS) $(CXXFLAGS) $< %.o : %.cp $(CXX) -c $(CPPFLAGS) $(CXXFLAGS) $< %.o : %.cxx $(CXX) -c $(CPPFLAGS) $(CXXFLAGS) $< # Rules for producing the executable. #---------------------------------------------- $(PROGRAM) : $(OBJS) ifeq ($(strip $(SRCEXTS)), .c) # C file $(CC) -o $(PROGRAM) $(OBJS) $(LDFLAGS) else # C++ file $(CXX) -o $(PROGRAM) $(OBJS) $(LDFLAGS) endif -include $(DEPS) rebuild: clean all clean : @$(RM) *.o *.d cleanall: clean @$(RM) $(PROGRAM) $(PROGRAM).exe