基于Crypto++/Cryptopp的rsa密钥生成，rsa加密、解密，rsa签名、验签12

在项目中需要增加一个注册的功能，想到了用rsa非对称加密的方法。对比了openssl等第三方库，最后采用了Cryptopp。

1.源文件整理

可以在http://www.cryptopp.com/获取库的源文件，解压后将文件重新归档。头文件放置到include文件夹，cpp放到src目录。同时去除所有的test相关的cpp及非cpp、h文件。拷本cryptopp目录到工程目录下

2.加入工程

在vs2010工程中增加新的filter，命名为Cryptopp，再增加子filter include和src。将include下的h文件导入到include，将src下的cpp导入到src filter。





3.编译

打开src，选中所有的cpp文件，更改属性，将预编译头改为pch.h。将工程的vc++路径更新，增加include和src。









编译工程，如果编译不过修改一下错误。

4.生成rsa公钥、私钥，经过base64编码后保存到文件

需要导入一些头文件：

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#include "iterhash.h"

#include "files.h"

#include "rsa.h"

#include "randpool.h"

#include "hex.h"

#include "base64.h"

#include "osrng.h"

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void CKeyController::GenerateRSAKey(unsigned int keyLength, CString decFilename, CString encFilename, CString seed)

{

RandomPool randPool;

randPool.Put((byte *)seed.GetBuffer(seed.GetLength()), seed.GetLength());

RSAES_OAEP_SHA_Decryptor decrypt(randPool, keyLength);

HexEncoder decFile(new Base64Encoder(new FileSink(decFilename.GetBuffer(decFilename.GetLength()))));

decrypt.DEREncode(decFile);

decFile.MessageEnd();

RSAES_OAEP_SHA_Encryptor encrypt(decrypt);

HexEncoder encFile(new Base64Encoder(new FileSink(encFilename.GetBuffer(encFilename.GetLength()))));

encrypt.DEREncode(encFile);

encFile.MessageEnd();

return;

}

RandomPool & CKeyController::GlobalRNG()

{

static RandomPool randomPool;

return randomPool;

}

5.通过生成的公钥文件加密字符串

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CString CKeyController::RSAEncryptString( CString encFilename, CString seed, CString message )

{

string encString;

FileSource encFile( encFilename.GetBuffer(encFilename.GetLength()), true, new Base64Decoder(new StringSink(encString)) );

HexDecoder decoder;

decoder.Put( (byte*)encString.c_str(), encString.size() );

decoder.MessageEnd();

RSAES_OAEP_SHA_Encryptor enc;

enc.AccessKey().Load(decoder);

RandomPool randPool;

randPool.Put( (byte *)seed.GetBuffer(seed.GetLength()), seed.GetLength() );

string result;

StringSource( c2s(message), true, new PK_EncryptorFilter(randPool, enc, new HexEncoder(new StringSink(result))) );

return CString(result.c_str());

}

6.通过生成的私钥文件解密字符串

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CString CKeyController::RSADecryptString( CString decFilename, CString ciphertext )

{

string decString;

FileSource decFile( decFilename.GetBuffer(decFilename.GetLength()), true, new Base64Decoder(new StringSink(decString)) );

HexDecoder decoder;

decoder.Put( (byte*)decString.c_str(), decString.size() );

decoder.MessageEnd();

RSAES_OAEP_SHA_Decryptor dec;

dec.AccessKey().Load(decoder);

string result;

StringSource( c2s(ciphertext), true, new HexDecoder(new PK_DecryptorFilter(GlobalRNG(), dec, new StringSink(result))) );

return CString(result.c_str());

}

7.使用私钥签名

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CString CKeyController::SignMessage( const std::string& privateKeyFileName, const std::string& message )

{

std::string signedMessage = "";

string encString;

FileSource privFile( privateKeyFileName.c_str(), true, new Base64Decoder(new StringSink(encString)));

RSASSA_PKCS1v15_SHA_Signer priv;

HexDecoder decoder;

decoder.Put( (byte*)encString.c_str(), encString.size() );

decoder.MessageEnd();

priv.AccessKey().Load(decoder);

AutoSeededRandomPool rng;

StringSource s1(message, true, new SignerFilter(rng, priv, new HexEncoder(new StringSink(signedMessage))));

return CString(signedMessage.c_str());

}

8.使用公钥验证签名

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bool CKeyController::VerifySignature( const std::string& publicKeyFileName, const std::string& message, const std::string& signedMessage )

{

string decString;

FileSource pubFile( publicKeyFileName.c_str(), true, new Base64Decoder(new StringSink(decString)) );

RSASSA_PKCS1v15_SHA_Verifier pub;

HexDecoder decoder;

decoder.Put( (byte*)decString.c_str(), decString.size() );

decoder.MessageEnd();

pub.AccessKey().Load(decoder);

StringSource signatureFile( signedMessage, true, new HexDecoder);

if (signatureFile.MaxRetrievable() != pub.SignatureLength())

{ throw std::string( "Signature Size Problem" ); }

SecByteBlock signature(pub.SignatureLength());

signatureFile.Get(signature, signature.size());

VerifierFilter *verifierFilter = new VerifierFilter(pub);

verifierFilter->Put(signature, pub.SignatureLength());

StringSource s(message, true, verifierFilter);

return verifierFilter->GetLastResult();

}

9.测试函数调用

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void CKeyController::testRSA()

{

CString encryptKey = _T("key.pub");

CString decryptKey = _T("key.pri");

CString seed = _T("seed");

//GenerateRSAKey( 1024, decryptKey, encryptKey, seed );

CString message = _T("X3BA-9NSF-8N9Q-UWQC-U7FX-AZZF-JAJW");

CString encryptedText = RSAEncryptString( encryptKey, seed, message );

CString decryptedText = RSADecryptString( decryptKey, encryptedText );

CString signedMessage = SignMessage("key.pri", c2s(decryptedText));

bool verified = VerifySignature("key.pub", c2s(message), c2s(signedMessage));

}

10.工具函数如base64转码，字符串转换

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std::string CKeyController::EncodeBase64( string message )

{

string encode;

StringSource(message, true, new Base64Encoder(new StringSink(encode)));

return encode;

}

std::string CKeyController::DecodeBase64( string message )

{

string decode;

StringSource(message, true, new Base64Decoder(new StringSink(decode)));

return decode;

}

CString CKeyController::hashString( CString message )

{

string digest;

SHA256 hash;

StringSource foo(c2s(message), true, new HashFilter(hash, new HexEncoder(new StringSink(digest))));

return CString(digest.c_str());

}

CString CKeyController::hashFile( CString fileName )

{

string digest;

SHA256 hash;

FileSource(fileName, true, new HashFilter(hash, new HexEncoder(new StringSink(digest))));

return CString(digest.c_str());

}

std::string c2s( CString &cs )

{

CT2CA pszConvertedAnsiString(cs);

std::string strStd(pszConvertedAnsiString);

return strStd;

}