RSA加密解密（無資料大小限制，php、go、java互通實現）
阿新 • • 發佈：2019-01-09
RSA加解密中必須考慮到的金鑰長度、明文長度和密文長度問題。明文長度需要小於金鑰長度，而密文長度則等於金鑰長度。因此當加密內容長度大於金鑰長度時，有效的RSA加解密就需要對內容進行分段。
這是因為，RSA演算法本身要求加密內容也就是明文長度m必須0<m<金鑰長度n。如果小於這個長度就需要進行padding，因為如果沒有padding，就無法確定解密後內容的真實長度，字串之類的內容問題還不大，以0作為結束符，但對二進位制資料就很難，因為不確定後面的0是內容還是內容結束符。而只要用到padding，那麼就要佔用實際的明文長度，於是實際明文長度需要減去padding位元組長度。我們一般使用的padding標準有NoPPadding、OAEPPadding、PKCS1Padding等，其中PKCS#1建議的padding就佔用了11個位元組。
這樣，對於1024長度的金鑰。128位元組（1024bits）-減去11位元組正好是117位元組，但對於RSA加密來講，padding也是參與加密的，所以，依然按照1024bits去理解，但實際的明文只有117位元組了。
Go實現
package xrsa import ( "encoding/pem" "encoding/base64" "crypto/x509" "crypto/rsa" "crypto/rand" "errors" "crypto" "io" "bytes" "encoding/asn1" ) const ( CHAR_SET = "UTF-8" BASE_64_FORMAT = "UrlSafeNoPadding" RSA_ALGORITHM_KEY_TYPE = "PKCS8" RSA_ALGORITHM_SIGN = crypto.SHA256 ) type XRsa struct { publicKey *rsa.PublicKey privateKey *rsa.PrivateKey } // 生成金鑰對 func CreateKeys(publicKeyWriter, privateKeyWriter io.Writer, keyLength int) error { // 生成私鑰檔案 privateKey, err := rsa.GenerateKey(rand.Reader, keyLength) if err != nil { return err } derStream := MarshalPKCS8PrivateKey(privateKey) block := &pem.Block{ Type: "PRIVATE KEY", Bytes: derStream, } err = pem.Encode(privateKeyWriter, block) if err != nil { return err } // 生成公鑰檔案 publicKey := &privateKey.PublicKey derPkix, err := x509.MarshalPKIXPublicKey(publicKey) if err != nil { return err } block = &pem.Block{ Type: "PUBLIC KEY", Bytes: derPkix, } err = pem.Encode(publicKeyWriter, block) if err != nil { return err } return nil } func NewXRsa(publicKey []byte, privateKey []byte) (*XRsa, error) { block, _ := pem.Decode(publicKey) if block == nil { return nil, errors.New("public key error") } pubInterface, err := x509.ParsePKIXPublicKey(block.Bytes) if err != nil { return nil, err } pub := pubInterface.(*rsa.PublicKey) block, _ = pem.Decode(privateKey) if block == nil { return nil, errors.New("private key error!") } priv, err := x509.ParsePKCS8PrivateKey(block.Bytes) if err != nil { return nil, err } pri, ok := priv.(*rsa.PrivateKey) if ok { return &XRsa { publicKey: pub, privateKey: pri, }, nil } else { return nil, errors.New("private key not supported") } } // 公鑰加密 func (r *XRsa) PublicEncrypt(data string) (string, error) { partLen := r.publicKey.N.BitLen() / 8 - 11 chunks := split([]byte(data), partLen) buffer := bytes.NewBufferString("") for _, chunk := range chunks { bytes, err := rsa.EncryptPKCS1v15(rand.Reader, r.publicKey, chunk) if err != nil { return "", err } buffer.Write(bytes) } return base64.RawURLEncoding.EncodeToString(buffer.Bytes()), nil } // 私鑰解密 func (r *XRsa) PrivateDecrypt(encrypted string) (string, error) { partLen := r.publicKey.N.BitLen() / 8 raw, err := base64.RawURLEncoding.DecodeString(encrypted) chunks := split([]byte(raw), partLen) buffer := bytes.NewBufferString("") for _, chunk := range chunks { decrypted, err := rsa.DecryptPKCS1v15(rand.Reader, r.privateKey, chunk) if err != nil { return "", err } buffer.Write(decrypted) } return buffer.String(), err } // 資料加簽 func (r *XRsa) Sign(data string) (string, error) { h := RSA_ALGORITHM_SIGN.New() h.Write([]byte(data)) hashed := h.Sum(nil) sign, err := rsa.SignPKCS1v15(rand.Reader, r.privateKey, RSA_ALGORITHM_SIGN, hashed) if err != nil { return "", err } return base64.RawURLEncoding.EncodeToString(sign), err } // 資料驗籤 func (r *XRsa) Verify(data string, sign string) error { h := RSA_ALGORITHM_SIGN.New() h.Write([]byte(data)) hashed := h.Sum(nil) decodedSign, err := base64.RawURLEncoding.DecodeString(sign) if err != nil { return err } return rsa.VerifyPKCS1v15(r.publicKey, RSA_ALGORITHM_SIGN, hashed, decodedSign) } func MarshalPKCS8PrivateKey(key *rsa.PrivateKey) []byte { info := struct { Version int PrivateKeyAlgorithm []asn1.ObjectIdentifier PrivateKey []byte }{} info.Version = 0 info.PrivateKeyAlgorithm = make([]asn1.ObjectIdentifier, 1) info.PrivateKeyAlgorithm[0] = asn1.ObjectIdentifier{1, 2, 840, 113549, 1, 1, 1} info.PrivateKey = x509.MarshalPKCS1PrivateKey(key) k, _ := asn1.Marshal(info) return k } func split(buf []byte, lim int) [][]byte { var chunk []byte chunks := make([][]byte, 0, len(buf)/lim+1) for len(buf) >= lim { chunk, buf = buf[:lim], buf[lim:] chunks = append(chunks, chunk) } if len(buf) > 0 { chunks = append(chunks, buf[:len(buf)]) } return chunks }
Php實現
if (! function_exists('url_safe_base64_encode')) { function url_safe_base64_encode ($data) { return str_replace(array('+','/', '='),array('-','_', ''), base64_encode($data)); } } if (! function_exists('url_safe_base64_decode')) { function url_safe_base64_decode ($data) { $base_64 = str_replace(array('-','_'),array('+','/'), $data); return base64_decode($base_64); } } class XRsa { const CHAR_SET = "UTF-8"; const BASE_64_FORMAT = "UrlSafeNoPadding"; const RSA_ALGORITHM_KEY_TYPE = OPENSSL_KEYTYPE_RSA; const RSA_ALGORITHM_SIGN = OPENSSL_ALGO_SHA256; protected $public_key; protected $private_key; protected $key_len; public function __construct($pub_key, $pri_key = null) { $this->public_key = $pub_key; $this->private_key = $pri_key; $pub_id = openssl_get_publickey($this->public_key); $this->key_len = openssl_pkey_get_details($pub_id)['bits']; } /* * 建立金鑰對 */ public static function createKeys($key_size = 2048) { $config = array( "private_key_bits" => $key_size, "private_key_type" => self::RSA_ALGORITHM_KEY_TYPE, ); $res = openssl_pkey_new($config); openssl_pkey_export($res, $private_key); $public_key_detail = openssl_pkey_get_details($res); $public_key = $public_key_detail["key"]; return [ "public_key" => $public_key, "private_key" => $private_key, ]; } /* * 公鑰加密 */ public function publicEncrypt($data) { $encrypted = ''; $part_len = $this->key_len / 8 - 11; $parts = str_split($data, $part_len); foreach ($parts as $part) { $encrypted_temp = ''; openssl_public_encrypt($part, $encrypted_temp, $this->public_key); $encrypted .= $encrypted_temp; } return url_safe_base64_encode($encrypted); } /* * 私鑰解密 */ public function privateDecrypt($encrypted) { $decrypted = ""; $part_len = $this->key_len / 8; $base64_decoded = url_safe_base64_decode($encrypted); $parts = str_split($base64_decoded, $part_len); foreach ($parts as $part) { $decrypted_temp = ''; openssl_private_decrypt($part, $decrypted_temp,$this->private_key); $decrypted .= $decrypted_temp; } return $decrypted; } /* * 私鑰加密 */ public function privateEncrypt($data) { $encrypted = ''; $part_len = $this->key_len / 8 - 11; $parts = str_split($data, $part_len); foreach ($parts as $part) { $encrypted_temp = ''; openssl_private_encrypt($part, $encrypted_temp, $this->private_key); $encrypted .= $encrypted_temp; } return url_safe_base64_encode($encrypted); } /* * 公鑰解密 */ public function publicDecrypt($encrypted) { $decrypted = ""; $part_len = $this->key_len / 8; $base64_decoded = url_safe_base64_decode($encrypted); $parts = str_split($base64_decoded, $part_len); foreach ($parts as $part) { $decrypted_temp = ''; openssl_public_decrypt($part, $decrypted_temp,$this->public_key); $decrypted .= $decrypted_temp; } return $decrypted; } /* * 資料加簽 */ public function sign($data) { openssl_sign($data, $sign, $this->private_key, self::RSA_ALGORITHM_SIGN); return url_safe_base64_encode($sign); } /* * 資料簽名驗證 */ public function verify($data, $sign) { $pub_id = openssl_get_publickey($this->public_key); $res = openssl_verify($data, url_safe_base64_decode($sign), $pub_id, self::RSA_ALGORITHM_SIGN); return $res; } }
Java實現
package com.inspii;
import org.apache.commons.codec.binary.Base64;
import org.apache.commons.io.IOUtils;
import javax.crypto.Cipher;
import java.io.ByteArrayOutputStream;
import java.security.*;
import java.security.interfaces.RSAPublicKey;
import java.security.interfaces.RSAPrivateKey;
import java.security.spec.PKCS8EncodedKeySpec;
import java.security.spec.X509EncodedKeySpec;
import java.util.HashMap;
import java.util.Map;
public class XRsa {
public static final String CHARSET = "UTF-8";
public static final String RSA_ALGORITHM = "RSA";
public static final String RSA_ALGORITHM_SIGN = "SHA256WithRSA";
private RSAPublicKey publicKey;
private RSAPrivateKey privateKey;
public XRsa(String publicKey, String privateKey)
{
try {
KeyFactory keyFactory = KeyFactory.getInstance(RSA_ALGORITHM);
//通過X509編碼的Key指令獲得公鑰物件
X509EncodedKeySpec x509KeySpec = new X509EncodedKeySpec(Base64.decodeBase64(publicKey));
this.publicKey = (RSAPublicKey) keyFactory.generatePublic(x509KeySpec);
//通過PKCS#8編碼的Key指令獲得私鑰物件
PKCS8EncodedKeySpec pkcs8KeySpec = new PKCS8EncodedKeySpec(Base64.decodeBase64(privateKey));
this.privateKey = (RSAPrivateKey) keyFactory.generatePrivate(pkcs8KeySpec);
} catch (Exception e) {
throw new RuntimeException("不支援的金鑰", e);
}
}
public static Map<String, String> createKeys(int keySize){
//為RSA演算法建立一個KeyPairGenerator物件
KeyPairGenerator kpg;
try{
kpg = KeyPairGenerator.getInstance(RSA_ALGORITHM);
}catch(NoSuchAlgorithmException e){
throw new IllegalArgumentException("No such algorithm-->[" + RSA_ALGORITHM + "]");
}
//初始化KeyPairGenerator物件,不要被initialize()源碼錶面上欺騙,其實這裡宣告的size是生效的
kpg.initialize(keySize);
//生成密匙對
KeyPair keyPair = kpg.generateKeyPair();
//得到公鑰
Key publicKey = keyPair.getPublic();
String publicKeyStr = Base64.encodeBase64URLSafeString(publicKey.getEncoded());
//得到私鑰
Key privateKey = keyPair.getPrivate();
String privateKeyStr = Base64.encodeBase64URLSafeString(privateKey.getEncoded());
Map<String, String> keyPairMap = new HashMap<String, String>();
keyPairMap.put("publicKey", publicKeyStr);
keyPairMap.put("privateKey", privateKeyStr);
return keyPairMap;
}
public String publicEncrypt(String data){
try{
Cipher cipher = Cipher.getInstance(RSA_ALGORITHM);
cipher.init(Cipher.ENCRYPT_MODE, publicKey);
return Base64.encodeBase64URLSafeString(rsaSplitCodec(cipher, Cipher.ENCRYPT_MODE, data.getBytes(CHARSET), publicKey.getModulus().bitLength()));
}catch(Exception e){
throw new RuntimeException("加密字串[" + data + "]時遇到異常", e);
}
}
public String privateDecrypt(String data){
try{
Cipher cipher = Cipher.getInstance(RSA_ALGORITHM);
cipher.init(Cipher.DECRYPT_MODE, privateKey);
return new String(rsaSplitCodec(cipher, Cipher.DECRYPT_MODE, Base64.decodeBase64(data), publicKey.getModulus().bitLength()), CHARSET);
}catch(Exception e){
throw new RuntimeException("解密字串[" + data + "]時遇到異常", e);
}
}
public String privateEncrypt(String data){
try{
Cipher cipher = Cipher.getInstance(RSA_ALGORITHM);
cipher.init(Cipher.ENCRYPT_MODE, privateKey);
return Base64.encodeBase64URLSafeString(rsaSplitCodec(cipher, Cipher.ENCRYPT_MODE, data.getBytes(CHARSET), publicKey.getModulus().bitLength()));
}catch(Exception e){
throw new RuntimeException("加密字串[" + data + "]時遇到異常", e);
}
}
public String publicDecrypt(String data){
try{
Cipher cipher = Cipher.getInstance(RSA_ALGORITHM);
cipher.init(Cipher.DECRYPT_MODE, publicKey);
return new String(rsaSplitCodec(cipher, Cipher.DECRYPT_MODE, Base64.decodeBase64(data), publicKey.getModulus().bitLength()), CHARSET);
}catch(Exception e){
throw new RuntimeException("解密字串[" + data + "]時遇到異常", e);
}
}
public String sign(String data){
try{
//sign
Signature signature = Signature.getInstance(RSA_ALGORITHM_SIGN);
signature.initSign(privateKey);
signature.update(data.getBytes(CHARSET));
return Base64.encodeBase64URLSafeString(signature.sign());
}catch(Exception e){
throw new RuntimeException("簽名字串[" + data + "]時遇到異常", e);
}
}
public boolean verify(String data, String sign){
try{
Signature signature = Signature.getInstance(RSA_ALGORITHM_SIGN);
signature.initVerify(publicKey);
signature.update(data.getBytes(CHARSET));
return signature.verify(Base64.decodeBase64(sign));
}catch(Exception e){
throw new RuntimeException("驗簽字符串[" + data + "]時遇到異常", e);
}
}
private static byte[] rsaSplitCodec(Cipher cipher, int opmode, byte[] datas, int keySize){
int maxBlock = 0;
if(opmode == Cipher.DECRYPT_MODE){
maxBlock = keySize / 8;
}else{
maxBlock = keySize / 8 - 11;
}
ByteArrayOutputStream out = new ByteArrayOutputStream();
int offSet = 0;
byte[] buff;
int i = 0;
try{
while(datas.length > offSet){
if(datas.length-offSet > maxBlock){
buff = cipher.doFinal(datas, offSet, maxBlock);
}else{
buff = cipher.doFinal(datas, offSet, datas.length-offSet);
}
out.write(buff, 0, buff.length);
i++;
offSet = i * maxBlock;
}
}catch(Exception e){
throw new RuntimeException("加解密閥值為["+maxBlock+"]的資料時發生異常", e);
}
byte[] resultDatas = out.toByteArray();
IOUtils.closeQuietly(out);
return resultDatas;
}
}參考
https://segmentfault.com/a/1190000011263680
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