java与openssl的rsa算法互用
说明
1.java生成的公私钥格式为 pkcs8, 而openssl默认生成的公私钥格式为 pkcs1，两者的密钥实际上是不能直接互用的
2.java采用的rsa默认补齐方式是pkcs1, 因此互用的时候需要将openssl中的补齐方式设置为RSA_PKCS1_PADDING
3.rsa加密中，加密数据长度有限制，不能超过密钥长度-11， 如密钥为1024位，则最长的加密数据位117字节； 加密后的密文长度总是为密钥的一半，即1024位的密文为512位
RSA加密常用的填充方式有下面3种：
1.RSA_PKCS1_PADDING 填充模式，最常用的模式
要求:
输入：必须 比 RSA 钥模长(modulus) 短至少11个字节, 也就是 RSA_size(rsa) – 11
如果输入的明文过长，必须切割， 然后填充
输出：和modulus一样长
根据这个要求，对于512bit的密钥， block length = 512/8 – 11 = 53 字节
2.RSA_PKCS1_OAEP_PADDING
输入：RSA_size(rsa) – 41
输出：和modulus一样长
3.for RSA_NO_PADDING 不填充
输入：可以和RSA钥模长一样长，如果输入的明文过长，必须切割， 然后填充
输出：和modulus一样长
Java的rsa封装
代码如下，从网上copy下来的，在此源码中，需要注意的是
cipher = Cipher.getInstance("RSA")
其中，这里可以选择rsa，也就默认了采用pkcs1补齐方式，也可以设置为其他的，如
cipher = Cipher.getInstance("RSA/ECB/NoPadding")
另外加密的数据是byte格式，即无符号字符，因此常见的算法是利用base64编码，将byte格式的转为String，因此这里也涉及到java与openssl的base64编码相互转换的问题
两者的输出格式是不同的，主要体现在换行的位置上，对openssl而言，base64编码后的换行主要是每64个出现一个换行；而java则是每76个字节出现一个换行，如果实际去测试，两者的base64编码解码是不能互用的。对于此，可以参考下面c的算法中的base64编码算法，屏蔽了换行的出现，这种情况下，java是可以解码openssl编码的结果的；相反，在openssl中，去掉换行后，也是可以处理java采用base64编码后的结果
import sun.misc.BASE64Encoder;
import sun.misc.BASE64Decoder;
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
import java.security.InvalidKeyException;
import java.security.Key;
import java.security.KeyFactory;
import java.security.KeyPair;
import java.security.KeyPairGenerator;
import java.security.NoSuchAlgorithmException;
import java.security.PrivateKey;
import java.security.PublicKey;
import java.security.interfaces.RSAPrivateKey;
import java.security.interfaces.RSAPublicKey;
import java.security.spec.PKCS8EncodedKeySpec;
import java.security.spec.X509EncodedKeySpec;
import java.util.HashMap;
import java.util.Map;
import javax.crypto.BadPaddingException;
import javax.crypto.Cipher;
import javax.crypto.IllegalBlockSizeException;
import javax.crypto.NoSuchPaddingException;
import sun.misc.BASE64Decoder;
import sun.misc.BASE64Encoder;
/**
* RSA算法，实现数据的加密解密。
* @author ShaoJiang
*
*/
class RSAUtil {
private static Cipher cipher;
static{
try {
cipher = Cipher.getInstance("RSA"); // RSA/ECB/NoPadding
} catch (NoSuchAlgorithmException e) {
e.printStackTrace();
} catch (NoSuchPaddingException e) {
e.printStackTrace();
}
}
/**
* 生成密钥对
* @param filePath 生成密钥的路径
* @return
*/
public static Map<String,String> generateKeyPair(String filePath){
try {
KeyPairGenerator keyPairGen = KeyPairGenerator.getInstance("RSA");
// 密钥位数
keyPairGen.initialize(1024);
// 密钥对
KeyPair keyPair = keyPairGen.generateKeyPair();
// 公钥
PublicKey publicKey = (RSAPublicKey) keyPair.getPublic();
// 私钥
PrivateKey privateKey = (RSAPrivateKey) keyPair.getPrivate();
//得到公钥字符串
String publicKeyString = getKeyString(publicKey);
//得到私钥字符串
String privateKeyString = getKeyString(privateKey);
//将密钥对写入到文件
FileWriter pubfw = new FileWriter(filePath+"/publicKey.keystore");
FileWriter prifw = new FileWriter(filePath+"/privateKey.keystore");
BufferedWriter pubbw = new BufferedWriter(pubfw);
BufferedWriter pribw = new BufferedWriter(prifw);
pubbw.write(publicKeyString);
pribw.write(privateKeyString);
pubbw.flush();
pubbw.close();
pubfw.close();
pribw.flush();
pribw.close();
prifw.close();
//将生成的密钥对返回
Map<String,String> map = new HashMap<String,String>();
map.put("publicKey",publicKeyString);
map.put("privateKey",privateKeyString);
return map;
} catch (Exception e) {
e.printStackTrace();
}
return null;
}
/**
* 得到公钥
*
* @param key
* 密钥字符串（经过base64编码）
* @throws Exception
*/
public static PublicKey getPublicKey(String key) throws Exception {
byte[] keyBytes;
keyBytes = (new BASE64Decoder()).decodeBuffer(key);
X509EncodedKeySpec keySpec = new X509EncodedKeySpec(keyBytes);
KeyFactory keyFactory = KeyFactory.getInstance("RSA");
PublicKey publicKey = keyFactory.generatePublic(keySpec);
return publicKey;
}
/**
* 得到私钥
*
* @param key
* 密钥字符串（经过base64编码）
* @throws Exception
*/
public static PrivateKey getPrivateKey(String key) throws Exception {
byte[] keyBytes;
keyBytes = (new BASE64Decoder()).decodeBuffer(key);
PKCS8EncodedKeySpec keySpec = new PKCS8EncodedKeySpec(keyBytes);
KeyFactory keyFactory = KeyFactory.getInstance("RSA");
PrivateKey privateKey = keyFactory.generatePrivate(keySpec);
return privateKey;
}
/**
* 得到密钥字符串（经过base64编码）
*
* @return
*/
public static String getKeyString(Key key) throws Exception {
byte[] keyBytes = key.getEncoded();
String s = (new BASE64Encoder()).encode(keyBytes);
return s;
}
/**
* 使用公钥对明文进行加密，返回BASE64编码的字符串
* @param publicKey
* @param plainText
* @return
*/
public static String encrypt(PublicKey publicKey,String plainText){
try {
cipher.init(Cipher.ENCRYPT_MODE, publicKey);
byte[] enBytes = cipher.doFinal(plainText.getBytes());
return (new BASE64Encoder()).encode(enBytes);
} catch (InvalidKeyException e) {
e.printStackTrace();
} catch (IllegalBlockSizeException e) {
e.printStackTrace();
} catch (BadPaddingException e) {
e.printStackTrace();
}
return null;
}
/**
* 使用keystore对明文进行加密
* @param publicKeystore 公钥文件路径
* @param plainText 明文
* @return
*/
public static String encrypt(String publicKeystore,String plainText){
try {
FileReader fr = new FileReader(publicKeystore);
BufferedReader br = new BufferedReader(fr);
String publicKeyString="";
String str;
while((str=br.readLine())!=null){
publicKeyString+=str;
}
br.close();
fr.close();
cipher.init(Cipher.ENCRYPT_MODE,getPublicKey(publicKeyString));
byte[] enBytes = cipher.doFinal(plainText.getBytes());
return (new BASE64Encoder()).encode(enBytes);
} catch (InvalidKeyException e) {
e.printStackTrace();
} catch (IllegalBlockSizeException e) {
e.printStackTrace();
} catch (BadPaddingException e) {
e.printStackTrace();
} catch (Exception e) {
e.printStackTrace();
}
return null;
}
/**
* 使用私钥对明文密文进行解密
* @param privateKey
* @param enStr
* @return
*/
public static String decrypt(PrivateKey privateKey,String enStr){
try {
cipher.init(Cipher.DECRYPT_MODE, privateKey);
byte[] deBytes = cipher.doFinal((new BASE64Decoder()).decodeBuffer(enStr));
return new String(deBytes);
} catch (InvalidKeyException e) {
e.printStackTrace();
} catch (IllegalBlockSizeException e) {
e.printStackTrace();
} catch (BadPaddingException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
return null;
}
/**
* 使用keystore对密文进行解密
* @param privateKeystore 私钥路径
* @param enStr 密文
* @return
*/
public static String decrypt(String privateKeystore,String enStr){
try {
FileReader fr = new FileReader(privateKeystore);
BufferedReader br = new BufferedReader(fr);
String privateKeyString="";
String str;
while((str=br.readLine())!=null){
privateKeyString+=str;
}
br.close();
fr.close();
cipher.init(Cipher.DECRYPT_MODE, getPrivateKey(privateKeyString));
byte[] deBytes = cipher.doFinal((new BASE64Decoder()).decodeBuffer(enStr));
return new String(deBytes);
} catch (InvalidKeyException e) {
e.printStackTrace();
} catch (IllegalBlockSizeException e) {
e.printStackTrace();
} catch (BadPaddingException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
} catch (Exception e) {
e.printStackTrace();
}
return null;
}
}
public class Hello{
// 将 s 进行 BASE64 编码
public static String getBASE64(String s) {
if (s == null) return null;
return (new sun.misc.BASE64Encoder()).encode( s.getBytes() );
}
// 将 BASE64 编码的字符串 s 进行解码
public static String getFromBASE64(String s) {
if (s == null) return null;
BASE64Decoder decoder = new BASE64Decoder();
try {
byte[] b = decoder.decodeBuffer(s);
return new String(b);
} catch (Exception e) {
return null;
}
}
public static void testBASE64()
{
String s = "1234567887654321123456788765432112345678876543211234567887654321123456788765432112345678876543211234567887654321123456788765432112345678876543211234567887654321";
System.out.println("length=" + s.length());
String ans = getBASE64(s);
System.out.println("length=" + ans.length());
System.out.println(ans);
String temp = "MTIzNDU2Nzg4NzY1NDMyMTEyMzQ1Njc4ODc2NTQzMjExMjM0NTY3ODg3NjU0MzIxMTIzNDU2Nzg4NzY1NDMyMTEyMzQ1Njc4ODc2NTQzMjE=";
String res = getFromBASE64(temp);
System.out.println(res);
System.out.println("----------------------------------------");
}
public static void main(String[] args)
{
RSAUtil util = new RSAUtil();
// util.generateKeyPair("key");
String cp = "M04d2l9MyDiUUfAQ32FdphesAQJHZUk0dEsYQcU06IJo/RCF311GtJXBK1FhapITIvjkpsiz9NR25AGEFPdz4bs2o5/F0QIj5yFA+biLxgcFrDpd5gSWI1F8V7wbsl06tNLNOVihFfzl8xWbHMVqPhY3tj8Vu/QHEPPnx7mvHlc="; // cp保存的是由openssl加密后的结果（包括了对密文的base64编码）
String cipher = util.encrypt("key/privateKey.keystore", "hello world");
String recover = util.decrypt("key/publicKey.keystore", cp);
System.out.println("cipher=" + cipher);
System.out.println("recover=" + recover);
}
}
Openssl的rsa算法
采用openssl的rsa算法实现公私钥加解密，这里由于项目需求，公私钥是使用java生成的，因此需要在密钥的首行和最后一行添加标记，两者对比如下：
--------java private key-------(本行不存在) MIICeAIBADANBgkqhkiG9w0BAQEFAASCAmIwggJeAgEAAoGBAKNQ3j+Ov9THQTMbNw+MwLOGRDwR qkiH0QffSLBh1Nv6JHBp7yC07b+Nj0lMiBOjoMpk98W3RTdDuRcJ/ojM0OMPZWNiOdvrtJ7I/Haw DiryMLqWR5gBCC0g+ODs2Cxr1ig5idNaX0bHy9ufSZpFd378OZLBVuOEBtQ7lnFhp/DxAgMBAAEC gYEAiOBLFPvAHUZOh9XEZPzzuMLMR4gKrrVd5PonguTLsP5KMgknCMN7C3NKZwWEeulF5ruOyh/b HAFfjEatFNyMKJnUhHwShvvSqncbZMBy9xmaA/FF0BUD285Vb+PhuPnL678KhEcKD3k99A+ym4qW K9abeiJypAfvnleopBFV+c0CQQDcdUrMdCVCdUIxenIjz67Qp6672iBC2Ni5psow2SZZ9FTC31Z5 7jDowqrvsABbY7XbV8g1LUX/U6JLylXiz7MrAkEAvaU16YtUCdVe4s6saNLnQCfi2ykVdn5ovy3R ZSn1gzQhy+//GFAhtUTjWO46zBicuNbJ1bNcaiF7DF4evU2OUwJBAJC14WqBlu+f3tpxoLjHG95V I4qlrOWUR/bdd/1GnTkQ/A6K4c3Zv3saRXBeXG2g7v/TCFV3qWnncTJE18mxQs8CQQCPVxNDvaK8 eADrD2lzJY3SiRNHsWrekDcd4US24RsHm1y8J185gj+oIjRwoEfiweubLgWKN7JvKXU26OD1Fmyv AkBR63yGMoIMo4AxLnkcr16j9WLBgQ/NXakPHcO2iMtFUsix3SNh96AkxZ+Fs87Ys70RuJOTtA/S llTOdaKm5PVqpc --------openssl private key-------(本行不存在) -----BEGIN RSA PRIVATE KEY-----（存在） MIICdgIBADANBgkqhkiG9w0BAQEFAASCAmAwggJcAgEAAoGBAKIpKYdHzzjEaugD55bBNlV+iJ60 w+C2fecv2ptenw7lUqDRiXTQsMXUiEBPKB5MLtJhLgB9yiph+lIN/lv+7GcPHaEjLwvh0ZnwXiQ2 sbL9sCzvU9r/2otJJ+2NrEf0PA4wEocrSiEv3at7oD3PCVps8nht3fzuPYfCxWhkBXeXAgMBAAEC gYAm/FZrm6wKLc618RpgeBsj+sPFxBfDkpw6VJrt95Wt8xwmZbnyR6n4JdyL+XvfrNkk4xA4NgXA osWXrJ2WaHdU/J0C1NnVzwMSISojR3+w5nsY5xyfdhPCNthlWnlmYTXJNOaQUGVO3oR1q0be+drt uQUV6yvsw/JDftskprqToQJBAOvObGbnz36YgdClJCVHZj3vFDlblAOiOFzIPq0hx72FpYcj/Ho3 3o5bAfZnHPMvOhbMaeY1xpm423f78qV2A+MCQQCwDDWM0uxvTA2XbpQGtVupZbqh/iZQ2eMYp8FJ t4aa/brUesXZurqsHWcrM6HrWp7gA6DzYeSSy6cCeVV6dlO9AkBaW7JMSH3JO/Valz1fj5mNGAT+ 6amxLsM8QntJ6ozYgdLpExAXYTtF/3ekDOUaBrnSrKfT0D13AFARDRlw7+UTAkAO7hokhUbT8Yk9 jH01THAnn58CWgF53eCqmJ+F1vCteFM97eOVoYZvTlcPjONwiFDtAqHFwkmWQXs6dHvRVPOpAkEA jalQvMpQM7Ej3s2oK386LVrH/La0hZZ6Fn4bgCJ26YxB3AGN5J8uHLjU5oBUMxDefc0OraDdyStJ pAh2vYzETw== -----END RSA PRIVATE KEY-----
下面是rsa的封装代码：
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <openssl/evp.h>
#include <openssl/aes.h>
#include <openssl/sha.h>
#include <openssl/hmac.h>
#include <openssl/bio.h>
#include <openssl/buffer.h>
#include <openssl/rsa.h>
#include <openssl/pem.h>
#include <openssl/err.h>
const char *RSA_SK = "privateKey.key";
const char *RSA_PK = "publicKey.key";
char *base64(const char *input, size_t length, char *result, size_t size)
{
BIO * bmem = NULL;
BIO * b64 = NULL;
BUF_MEM * bptr = NULL;
b64 = BIO_new(BIO_f_base64());
BIO_set_flags(b64, BIO_FLAGS_BASE64_NO_NL);
bmem = BIO_new(BIO_s_mem());
b64 = BIO_push(b64, bmem);
BIO_write(b64, input, length);
BIO_flush(b64);
BIO_get_mem_ptr(b64, &bptr);
if(bptr->length + 1 > size)
{
BIO_free_all(b64);
return NULL;
}
memcpy(result, bptr->data, bptr->length);
result[bptr->length] = 0;
BIO_free_all(b64);
return result;
}
char *debase64(char *input, size_t length, char *result, size_t size)
{
BIO * b64 = NULL;
BIO * bmem = NULL;
if(length > size)
return NULL;
memset(result, 0, size);
b64 = BIO_new(BIO_f_base64());
BIO_set_flags(b64, BIO_FLAGS_BASE64_NO_NL);
bmem = BIO_new_mem_buf(input, length);
bmem = BIO_push(b64, bmem);
BIO_read(bmem, result, length);
BIO_free_all(bmem);
return result;
}
char *rsa_encrypt(const char *plain_text, char *result, size_t size, const char *pk_filename)
{
unsigned char *cipher;
int len;
RSA *rsa;
FILE *file;
if (NULL == (file = fopen(pk_filename, "rb")))
{
fprintf(stderr, "%s public key file not exist!\n", pk_filename);
return NULL ;
}
if (NULL == (rsa = PEM_read_RSA_PUBKEY(file, NULL, NULL, NULL )))
{
ERR_print_errors_fp(stdout);
return NULL ;
}
fclose(file);
len = RSA_size(rsa);
if (NULL == (cipher = (unsigned char *) malloc(len + 1)))
{
RSA_free(rsa);
return NULL ;
}
memset(cipher, 0, len + 1);
if (0
> RSA_public_encrypt(strlen(plain_text), (unsigned char *) plain_text,
(unsigned char*) cipher, rsa, RSA_PKCS1_PADDING))// 这里设置填充方式，注意java和openssl的统一
{
RSA_free(rsa);
free(cipher);
return NULL ;
}
RSA_free(rsa);
base64((char *) cipher, strlen((char *) cipher), result, size);
free(cipher);
return result;
}
char *rsa_decrypt(char *cipher, char *plain_text, size_t size, const char *sk_filename)
{
FILE *file = NULL;
RSA *rsa;
int len;
if (NULL == (file = fopen(sk_filename, "rb")))
{
fprintf(stderr, "%s private key file not exist!\n", sk_filename);
return NULL ;
}
if ((rsa = PEM_read_RSAPrivateKey(file, NULL, NULL, NULL )) == NULL )
{
ERR_print_errors_fp(stdout);
return NULL ;
}
fclose(file);
len = RSA_size(rsa);
memset(plain_text, 0, size);
char temp[250];
if(NULL == debase64(cipher, strlen(cipher), temp, 250))
{
RSA_free(rsa);
fprintf(stderr, "decrypt error\n");
return NULL;
}
if (0
> RSA_private_decrypt(len, (unsigned char *) temp,
(unsigned char*) plain_text, rsa, RSA_PKCS1_PADDING))
{
RSA_free(rsa);
return NULL ;
}
RSA_free(rsa);
return plain_text;
}
char *rsa_sign(const char *text, char *signature, size_t size, const char *sk_filename)
{
RSA *rsa;
FILE *file;
unsigned char *sig;
unsigned int sig_len;
if (NULL == (file = fopen(sk_filename, "rb")))
{
printf("error:open key file error\n");
return NULL ;
}
if ((rsa = PEM_read_RSAPrivateKey(file, NULL, NULL, NULL )) == NULL )
{
ERR_print_errors_fp(stdout);
return NULL ;
}
fclose(file);
if (NULL == (sig = (unsigned char*) malloc(RSA_size(rsa))))
{
RSA_free(rsa);
return NULL ;
}
unsigned char temp[20];
SHA((const unsigned char *) text, strlen(text), temp);
if (1 != RSA_sign(NID_sha1, temp, 20, sig, &sig_len, rsa))
{
printf("error:fail to sign the message!\n");
free(sig);
RSA_free(rsa);
return NULL ;
}
RSA_free(rsa);
base64((char *) sig, strlen((char *) sig), signature, size);
free(sig);
return signature;
}
int rsa_verify(const char *text, char *sig, const char *pk_filename)
{
RSA *rsa;
FILE *file;
if (NULL == (file = fopen(pk_filename, "rb")))
{
printf("error:open key file error\n");
return -1;
}
if ((rsa = PEM_read_RSA_PUBKEY(file, NULL, NULL, NULL )) == NULL )
{
ERR_print_errors_fp(stdout);
return -1;
}
fclose(file);
unsigned char sig_temp[250];
if(NULL == debase64(sig, strlen((char *) sig), sig_temp, 250))
{
fprintf(stderr, "verify debase error\n");
return -1;
}
unsigned char temp[20];
SHA((const unsigned char *) text, strlen(text), temp);
int ret = RSA_verify(NID_sha1, temp, 20, (unsigned char *)sig_temp, 128, rsa);
RSA_free(rsa);
return (ret == 1) ? 0 : -1;
}
int main()
{
char *temp = ",./qer/0qwertyui";
char ans[500];
rsa_encrypt(temp, ans, 500, RSA_PK);
printf("cipher = %s\n", ans);
char result[1024];
rsa_decrypt(ans, result, 1024, RSA_SK);
printf("recover = %s\n", result);
char sig[1024];
rsa_sign(temp, sig, 1024, RSA_SK);
int v = rsa_verify(temp, sig, RSA_PK);
printf("The v = %d\n", v);
char *c = "SLaUQRk9rAkkoqve3cyo3DwX4Rd8IPYKCLb01tpW/i9444WptaDviD6J+NN03xlGF8MO0STdZ1wf3ZimBKcPwRz0ecHdNtWQ8ol4f3ZUo74x4oyDmtsLPI2yMDgsL0C5+GBnxWtUFPr4bJw+Uk4F78upnNx93dV8PNS+Q7MfArk="; // java加密后的结果
char r[1024];
rsa_decrypt(c, r, 1024, RSA_SK);
printf("The r = %s--\n", r);
char db[100];
debase64(r, strlen(r), db, 100);
int i = 0;
while(i < strlen(db))
printf("-%x", (unsigned char)db[i++]);
printf("---%d--\n", strlen(db));
return 0;
}