javarsa代码 java代码例子讲解( 九 )


result = new String(resultBytes);
} catch (Exception e) {
throw new Exception(e);
}
return result;
}
private static void write2Stream(Cipher cipher, byte[] data, ByteArrayOutputStream out) throws
BadPaddingException, IllegalBlockSizeException {
int dataLen = data.length;
int offSet = 0;
byte[] cache;
int i = 0;
// 对数据分段解密
while (dataLen - offSet0) {
if (dataLen - offSetMAX_DECRYPT_BLOCK) {
cache = cipher.doFinal(data, offSet, MAX_DECRYPT_BLOCK);
} else {
cache = cipher.doFinal(data, offSet, dataLen - offSet);
}
out.write(cache, 0, cache.length);
i++;
offSet = i * MAX_DECRYPT_BLOCK;
}
}
/**
* 用私钥对信息生成数字签名
*
* @param data已加密数据
* @param privateKey 私钥(BASE64编码)
* @return sign
*/
public String sign(String data, String privateKey) throws Exception {
String result = "";
try {
byte[] keyBytes = new Base64().decode(privateKey);
PKCS8EncodedKeySpec pkcs8KeySpec = new PKCS8EncodedKeySpec(keyBytes);
PrivateKey privateK = keyFactory.generatePrivate(pkcs8KeySpec);
Signature signature = Signature.getInstance(SIGNATURE_ALGORITHM);
signature.initSign(privateK);
signature.update(parse2HexStr(data).getBytes(CHARSET));
result = new Base64().encodeToString(signature.sign());
} catch (Exception e) {
throw new Exception(e);
}
return result;
}
/**
* 校验数字签名
*
* @param data已加密数据
* @param publicKey 公钥(BASE64编码)
* @param sign数字签名
* @return
* @throws Exception
*/
public boolean verify(String data, String publicKey, String sign) throws Exception {
boolean result;
try {
byte[] keyBytes = new Base64().decode(publicKey);
X509EncodedKeySpec keySpec = new X509EncodedKeySpec(keyBytes);
PublicKey publicK = keyFactory.generatePublic(keySpec);
Signature signature = Signature.getInstance(SIGNATURE_ALGORITHM);
signature.initVerify(publicK);
signature.update(parse2HexStr(data).getBytes(CHARSET));
result = signature.verify(new Base64().decode(sign));
} catch (Exception e) {
throw new Exception(e);
}
return result;
}
/**
* 将二进制转换成16进制
*
* @param data
* @return
*/
public static String parse2HexStr(String data) throws Exception {
String result = "";
try {
byte[] buf = data.getBytes(CHARSET);
StringBuffer sb = new StringBuffer();
for (int i = 0; ibuf.length; i++) {
String hex = Integer.toHexString(buf[i]0xFF);
if (hex.length() == 1) {
hex = '0' + hex;
}
sb.append(hex.toUpperCase());
}
result = sb.toString();
} catch (UnsupportedEncodingException e) {
throw new Exception(e);
}
return result;
}
/**
* 生成公钥与私钥
*/
public static void createKey() throws Exception {
try {
KeyPairGenerator keyPairGenerator = KeyPairGenerator.getInstance(ALGORITHM);
keyPairGenerator.initialize(KEY_SIZE);
KeyPair keyPair = keyPairGenerator.generateKeyPair();
RSAPublicKey rsaPublicKey = (RSAPublicKey) keyPair.getPublic();
RSAPrivateKey rsaPrivateKey = (RSAPrivateKey) keyPair.getPrivate();
String publicKey = Base64.encodeBase64String(rsaPublicKey.getEncoded());
String privateKey = Base64.encodeBase64String(rsaPrivateKey.getEncoded());
System.out.println("publicKey=" + publicKey + "\nprivateKey=" + privateKey);
} catch (NoSuchAlgorithmException e) {
throw new Exception(e);
}
}
public static void main(String[] args) throws Exception {
String PRIVATE_KEY = "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";

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