我正在开发一个使用RSA和AES算法混合的j2me应用程序。 RSA密钥用于安全密钥交换目的，而AES用于消息加密。应用程序需要生成RSA密钥并将其存储/写入移动设备上的安全位置，并在需要时从设备读取。我使用代码生成了密钥（来自Michael Juntao的书籍“enterprise j2me”）;
public void generateRSAKeyPair () throws Exception {
SecureRandom sr = new SecureRandom();
BigInteger pubExp = new BigInteger("10001", 16);
RSAKeyGenerationParameters RSAKeyGenPara =
new RSAKeyGenerationParameters(pubExp, sr, 1024, 80);
RSAKeyPairGenerator RSAKeyPairGen = new RSAKeyPairGenerator();
RSAKeyPairGen.init(RSAKeyGenPara);
AsymmetricCipherKeyPair keyPair = RSAKeyPairGen.generateKeyPair();
RSAprivKey = (RSAPrivateCrtKeyParameters) keyPair.getPrivate();
RSApubKey = (RSAKeyParameters) keyPair.getPublic();
}
在同一本书中，以下代码用于写入密钥。但是，我发现CLDC不支持此处使用的FileOutputStream（）类（仅在CDC和J2SE中支持）。
BigInteger mod = RSAprivKey.getModulus();
out = new FileOutputStream(outdir + "RSAmod.dat");
out.write(mod.toByteArray());
out.flush(); out.close();
BigInteger privExp = RSAprivKey.getExponent();
out = new FileOutputStream(outdir + "RSAprivExp.dat");
out.write(privExp.toByteArray());
out.flush(); out.close();
pubExp = RSAprivKey.getPublicExponent();
if ( !pubExp.equals(new BigInteger("10001", 16)) )
throw new Exception("wrong public exponent");
out = new FileOutputStream(outdir + "RSApubExp.dat");
out.write(pubExp.toByteArray());
out.flush(); out.close();
BigInteger dp = RSAprivKey.getDP();
out = new FileOutputStream(outdir + "RSAdp.dat");
out.write(dp.toByteArray());
out.flush(); out.close();
BigInteger dq = RSAprivKey.getDQ();
out = new FileOutputStream(outdir + "RSAdq.dat");
out.write(dq.toByteArray());
out.flush(); out.close();
BigInteger p = RSAprivKey.getP();
out = new FileOutputStream(outdir + "RSAp.dat");
out.write(p.toByteArray());
out.flush(); out.close();
BigInteger q = RSAprivKey.getQ();
out = new FileOutputStream(outdir + "RSAq.dat");
out.write(q.toByteArray());
out.flush(); out.close();
BigInteger qInv = RSAprivKey.getQInv();
out = new FileOutputStream(outdir + "RSAqInv.dat");
out.write(qInv.toByteArray());
out.flush(); out.close();
请帮我完成如何编写和阅读RSA密钥。
答案 0 :(得分：0)
我使用RecordStore（RMS）来存储密钥。 Recordstore中可以存储三种数据类型：String，byte和Int。但是，RSA密钥的组件是BigInteger数据类型。因此，我已经获得了一个＆＃34;字符串＆＃34;每个关键组件的表示/等效如下;
//method for serializing the key components
public void SerializeRSAKeyPair()
{
BigInteger mod = RSAprivKey.getModulus();
String mods = mod.toString();// converts to String representation
BigInteger privExp = RSAprivKey.getExponent();
String privExps = privExp.toString(); // converts to String representation
BigInteger pubExp = RSAprivKey.getPublicExponent();
String pubExps = pubExp.toString();//..same
BigInteger dp = RSAprivKey.getDP();
String dps = dp.toString();
BigInteger dq = RSAprivKey.getDQ();
String dqs = dq.toString();
BigInteger p = RSAprivKey.getP();
String ps = p.toString();
BigInteger q = RSAprivKey.getQ();
String qs = q.toString();
BigInteger qInv = RSAprivKey.getQInv();
String qInvs = qInv.toString();
String [] RSAstrings = {mods, privExps,pubExps,dps,dqs, ps,qs,qInvs};
// all combined to a String array
writeStream(strings);
}
//Write the String array RSAKeyPairStore Recordstore
public void writeStream(String[] sData)
{
try
{
// Write data into an internal byte array
ByteArrayOutputStream strmBytes =
new ByteArrayOutputStream();
// Write Java data types into the above byte array
DataOutputStream strmDataType =
new DataOutputStream(strmBytes);
byte[] record;
for (int i = 0; i < sData.length; i++)
{
// Write Java String data
strmDataType.writeUTF(sData[i]);
// Clear any buffered data
strmDataType.flush();
// Get stream data into byte array and write record
record = strmBytes.toByteArray();
RSAKeyPairStore.addRecord(record, 0, record.length);
strmBytes.reset();
}
strmBytes.close();
strmDataType.close();
}
catch (Exception e)
{
db(e.toString());
}
}
private void db(String str)
{
System.err.println("Msg: " + str);
}
// To read the keys create separate methods for reading Public Keys and private keys
//the record store using streams.
public void readRSApublic()
{
try
{
byte[] recData = new byte[100];
ByteArrayInputStream strmBytes =
new ByteArrayInputStream(recData);
// Read data from the above byte array
DataInputStream strmDataType =
new DataInputStream(strmBytes);
// since only the modulus and public exponents are required for computing RSA Public keys,
//we read record 1 and 3 as follows
RSAKeyPairStore.getRecord(1, recData, 0);
String mod = strmDataType.readUTF();
//System.out.println ("mod = " + mod);// use this to confirm that its equal to the BigInteger/equivalent below
BigInteger RSAmod = new BigInteger(mod);
//System.out.println ("RSAmod = " + RSAmod);
//use this confirm its equal to the string equivalent above
strmBytes.reset();
RSAKeyPairStore.getRecord(3, recData, 0);
String pubExp = strmDataType.readUTF();
//System.out.println ("pubExp = " + pubExp);
BigInteger RSApubExp = new BigInteger(pubExp);
//System.out.println ("RSApubExp = " + RSApubExp);
strmBytes.reset();
//then reconstruct the public key from the retrieved records
newRSApubKey = new RSAKeyParameters(false, RSAmod, RSApubExp);
// then use the key for the purpose you want e.g for encryption of data
strmBytes.close();
strmDataType.close();
}
catch (Exception e)
{
db(e.toString());
}
}
// when you need the private key, do the same; Retrieve (as strings)all the components that makes up the private key namely; and then convert them to BigInteger equivalents and then reconstruct as above
public void readRSAprivate()
{
try
{
byte[] recData = new byte[500];
ByteArrayInputStream strmBytes =
new ByteArrayInputStream(recData);
// Read Java data types from the above byte array
DataInputStream strmDataType =
new DataInputStream(strmBytes);
RSAKeyPairStore.getRecord(1, recData, 0);
String mod = strmDataType.readUTF();
//System.out.println ("mod = " + mod);
BigInteger RSAmod = new BigInteger(mod);
strmBytes.reset();
RSAKeyPairStore.getRecord(2, recData, 0);
String privExp = strmDataType.readUTF();
//System.out.println ("privExp = " + privExp);
BigInteger RSAprivExp = new BigInteger(privExp);
//System.out.println ("RSAprivExp = " + RSAprivExp);
strmBytes.reset();
RSAKeyPairStore.getRecord(3, recData, 0);
String pubExp = strmDataType.readUTF();
BigInteger RSApubExp = new BigInteger(pubExp);
strmBytes.reset();
RSAKeyPairStore.getRecord(4, recData, 0);
String dps = strmDataType.readUTF();
BigInteger RSAdp = new BigInteger(dps);
strmBytes.reset();
RSAKeyPairStore.getRecord(5, recData, 0);
String dqs = strmDataType.readUTF();
BigInteger RSAdq = new BigInteger(dqs);
strmBytes.reset();
RSAKeyPairStore.getRecord(6, recData, 0);
String p = strmDataType.readUTF();
BigInteger RSAp = new BigInteger(p);
strmBytes.reset();
RSAKeyPairStore.getRecord(7, recData, 0);
String q = strmDataType.readUTF();
BigInteger RSAq = new BigInteger(q);
strmBytes.reset();
RSAKeyPairStore.getRecord(8, recData, 0);
String qInv = strmDataType.readUTF();
BigInteger RSAqInv = new BigInteger(qInv);
strmBytes.reset();
// then use the key for the purpose you want e.g for Signing
newRSAprivKey = new RSAPrivateCrtKeyParameters(RSAmod, RSAprivExp, RSApubExp, RSAp,
RSAq, RSAdp, RSAdq, RSAqInv);
strmBytes.close();
strmDataType.close();
}
catch (Exception e)
{
db(e.toString());
}
}