深入理解签名验签

柔情只为你懂 2022-05-30 08:18 309阅读 0赞

数字签名中,包含了两个过程:  
1.对要签名的信息,用指定的hash算法,获取信息的hash值.  
2.用私钥,对hash值进行加密,输出加密串(也就是签名值).  
以上方式也就是裸签名,PKCS\#1

验证签名:  
1.对要签名的信息(也就是签名原文),用指定的hash算法,获取信息的hash值.  
2.用公钥信息,解密签名值,从中获取加密的hash串,和上面获取的hash值进行对比,一致则认为验签通过,不一致则不通过.

需要主要,如果调用远程签名,因为根据要签名的数据格式的不同,所以我们本地验签的时候,也要根据不同的签名方式,来进行验证(也就说,他们那边签名的时候,真正用来签名的字节数组是怎么来的)

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目前常见的几种方式:(P1签名验签)

contentType==CT_MESSAGE时，为待签名的消息；
    contentType==CT_BASE64_DATA时，为待签名的base64编码数据；
    contentType==CT_HASH时为待签名的HASH；
    contentType==CT_FILE_URL时为待签名文件地址URL
    contentType== CT_STORAGE时为待签名内容存储编号

CT\_HASH:告诉签名方,我这个是对签名原文hash过了的hash串,你们直接对这个值进行加密即可,不需要再hash了.  
所以这种方式,我们本地验签的时候,要将原文放入进行验签,而不是hash过后的hash值(因为验签的时候,它又会hash一次)

/** * 测试hash方式的签名验签 * @throws Exception */
        @Test
        public void testSignWithHash() {
            try {
                CertificateFactory cf = CertificateFactory.getInstance("X.509"); 
                Certificate usercert = cf.generateCertificate(new FileInputStream(USER_CERT)); 
                PublicKey publicKey = usercert.getPublicKey();
                //读取pfx证书上的秘钥对信息
                BouncyCastleProvider provider = new BouncyCastleProvider();
                Signature signature = Signature.getInstance("SHA1withRSA"); 
                MessageDigest digest = MessageDigest.getInstance("SHA-1", provider);
    
                List<UserInfo> userInfoList = userInfoService.findAll();
                UserInfo userInfo = userInfoList.get(0);
                Map<String, Object> puserCert = new HashMap<>();
                puserCert.put("userInfo", userInfo);
                List<UserCert> userCertList = userCertService.getListByParam(puserCert);
                UserCert userCert = userCertList.get(0);
                YuanZi_P1SignRequest yuanZiP1SignRequest = new YuanZi_P1SignRequest();
                yuanZiP1SignRequest.setAlias(userInfo.getAlias());
                yuanZiP1SignRequest.setHashAlg("SHA1");
                yuanZiP1SignRequest.setContentType("CT_HASH");
                String content = "我是签名原文";
    
                byte[] dataToSign = digest.digest(content.getBytes(Charset.forName("UTF-8")));
                System.out.println("dataToSign:"+Base64.encodeBytes(dataToSign));
                yuanZiP1SignRequest.setContent(Base64.encodeBytes(dataToSign));
                YuanZi_P1SignResponse yuanZiP1SignResponse = yuanZiService.signP1(yuanZiP1SignRequest);
                System.out.println("原子服务返回的签名值:"+yuanZiP1SignResponse.getSignedData());
                byte[] dataHadSignature = Base64.decode(yuanZiP1SignResponse.getSignedData());
    
                YuanZi_VerifyP1SignRequest yuanZiVerifyP1SignRequest = new YuanZi_VerifyP1SignRequest();
                yuanZiVerifyP1SignRequest.setSignedData(yuanZiP1SignResponse.getSignedData());
                yuanZiVerifyP1SignRequest.setContentType("CT_HASH");
                yuanZiVerifyP1SignRequest.setContent(Base64.encodeBytes(dataToSign));
                yuanZiVerifyP1SignRequest.setHashAlg("SHA1");
                yuanZiVerifyP1SignRequest.setCert(userCert.getCertBuf().getCertsignBuf());
                YuanZi_VerifyP1SignResponse yuanZiVerifyP1SignResponse = yuanZiService.verifyP1Sign(yuanZiVerifyP1SignRequest);
                System.out.println(yuanZiVerifyP1SignResponse.getCode());
    
                //本地验签
                boolean verify=false; 
                signature.initVerify(usercert); //使用公钥初始化签名对象,用于验证签名 
                signature.update(content.getBytes(Charset.forName("UTF-8")));
                verify= signature.verify(dataHadSignature); //得到验证结果 
                System.out.println("本地的验签结果:"+verify);
            } catch (Exception e) {
                e.printStackTrace();
                // TODO: handle exception
            }
        }

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CT\_MESSAGE:即,告诉签名方,我发过去的内容,就是签名的原文.一般来说,因为签名值都是字节数组,所以签名方会根据约定的编码方式,对这个签名原文按规定的编码方式,取它的字节数组之后,进行签名

我们本地验签的时候,也要对原文做同样的操作

/** * 测试原子服务P1方式的签名和验签通过 * @throws Exception */
            @Test
            public void testSign_P1_CT_MESSAGE() {
                try {
                    CertificateFactory cf = CertificateFactory.getInstance("X.509"); 
                    Certificate usercert = cf.generateCertificate(new FileInputStream(USER_CERT)); 
                    PublicKey publicKey = usercert.getPublicKey();
                    //读取pfx证书上的秘钥对信息
                    BouncyCastleProvider provider = new BouncyCastleProvider();
                    Signature signature = Signature.getInstance("SHA1withRSA"); 
                    MessageDigest digest = MessageDigest.getInstance("SHA-1", provider);
    
                    List<UserInfo> userInfoList = userInfoService.findAll();
                    UserInfo userInfo = userInfoList.get(0);
                    Map<String, Object> puserCert = new HashMap<>();
                    puserCert.put("userInfo", userInfo);
                    List<UserCert> userCertList = userCertService.getListByParam(puserCert);
                    UserCert userCert = userCertList.get(0);
                    YuanZi_P1SignRequest yuanZiP1SignRequest = new YuanZi_P1SignRequest();
                    yuanZiP1SignRequest.setAlias(userInfo.getAlias());
                    yuanZiP1SignRequest.setHashAlg("SHA1");
                    yuanZiP1SignRequest.setContentType("CT_MESSAGE");
                    String content = "我是签名原文";
                    yuanZiP1SignRequest.setContent(content);
                    YuanZi_P1SignResponse yuanZiP1SignResponse = yuanZiService.signP1(yuanZiP1SignRequest);
                    System.out.println("原子服务返回的签名值:"+yuanZiP1SignResponse.getSignedData());
                    byte[] dataHadSignature = Base64.decode(yuanZiP1SignResponse.getSignedData());
    
                    YuanZi_VerifyP1SignRequest yuanZiVerifyP1SignRequest = new YuanZi_VerifyP1SignRequest();
                    yuanZiVerifyP1SignRequest.setSignedData(yuanZiP1SignResponse.getSignedData());
                    yuanZiVerifyP1SignRequest.setContentType("CT_MESSAGE");
                    yuanZiVerifyP1SignRequest.setContent(content);
                    yuanZiVerifyP1SignRequest.setHashAlg("SHA1");
                    yuanZiVerifyP1SignRequest.setCert(userCert.getCertBuf().getCertsignBuf());
                    YuanZi_VerifyP1SignResponse yuanZiVerifyP1SignResponse = yuanZiService.verifyP1Sign(yuanZiVerifyP1SignRequest);
                    System.out.println(yuanZiVerifyP1SignResponse.getCode());
    
                    //本地验签
                    boolean verify=false; 
                    signature.initVerify(usercert); //使用公钥初始化签名对象,用于验证签名 
                    signature.update(content.getBytes(Charset.forName("UTF-8")));
                    verify= signature.verify(dataHadSignature); //得到验证结果 
                    System.out.println("本地的验签结果:"+verify);
    
    
                } catch (Exception e) {
                    e.printStackTrace();
                    // TODO: handle exception
                }
    
            }

--------------------

CT\_BASE64\_DATA:因为有时候,我们要签名的原文,它就是一个byte\[\],但是为了方便传输,一般签名方都要求接受的是一个字符串.所以就有了这种签名方式.即:我们需要对签名原文的byte\[\]做base64编码,签名方收到之后,再做解码,并且把解码后的byte\[\]进行签名.  
所以我们本身验签的时候,只要传入byte\[\]就行.  
第三方返回的签名值,一般也是签名值byte\[\]做base64编码后的字符串,所以我们要做base64解码,才能获取到签名值byte\[\].

/** * 测试原子服务P1方式的CT_BASE64_DATA签名和验签通过 * @throws Exception * * 注意多种签名方式,你传给它要签名的数据,和它最后执行签名的时候,真正要签的那个原文可能跟你传的不是同一个(比如需要做String 转为byte,base64编码要解码) */
            @Test
            public void testSign_P1_CT_BASE64_DATA() {
                try {
                    CertificateFactory cf = CertificateFactory.getInstance("X.509"); 
                    Certificate usercert = cf.generateCertificate(new FileInputStream(USER_CERT)); 
                    PublicKey publicKey = usercert.getPublicKey();
                    //读取pfx证书上的秘钥对信息
                    BouncyCastleProvider provider = new BouncyCastleProvider();
                    Signature signature = Signature.getInstance("SHA1withRSA"); 
                    MessageDigest digest = MessageDigest.getInstance("SHA-1", provider);
    
                    List<UserInfo> userInfoList = userInfoService.findAll();
                    UserInfo userInfo = userInfoList.get(0);
                    Map<String, Object> puserCert = new HashMap<>();
                    puserCert.put("userInfo", userInfo);
                    List<UserCert> userCertList = userCertService.getListByParam(puserCert);
                    UserCert userCert = userCertList.get(0);
                    YuanZi_P1SignRequest yuanZiP1SignRequest = new YuanZi_P1SignRequest();
                    yuanZiP1SignRequest.setAlias(userInfo.getAlias());
                    yuanZiP1SignRequest.setHashAlg("SHA1");
                    yuanZiP1SignRequest.setContentType("CT_BASE64_DATA");
                    byte[] dataToSign = new byte[10];
                    String base64ToSign = Base64.encodeBytes(dataToSign);
    
                    yuanZiP1SignRequest.setContent(base64ToSign);
                    YuanZi_P1SignResponse yuanZiP1SignResponse = yuanZiService.signP1(yuanZiP1SignRequest);
                    System.out.println("原子服务返回的签名状态:"+yuanZiP1SignResponse.getCode());
                    System.out.println("原子服务返回的签名值:"+yuanZiP1SignResponse.getSignedData());
                    //签名后的
                    byte[] dataHadSignature = Base64.decode(yuanZiP1SignResponse.getSignedData());
    
                    YuanZi_VerifyP1SignRequest yuanZiVerifyP1SignRequest = new YuanZi_VerifyP1SignRequest();
                    yuanZiVerifyP1SignRequest.setSignedData(yuanZiP1SignResponse.getSignedData());
                    yuanZiVerifyP1SignRequest.setContentType("CT_BASE64_DATA");
                    yuanZiVerifyP1SignRequest.setContent(base64ToSign);
                    yuanZiVerifyP1SignRequest.setHashAlg("SHA1");
                    yuanZiVerifyP1SignRequest.setCert(userCert.getCertBuf().getCertsignBuf());
                    YuanZi_VerifyP1SignResponse yuanZiVerifyP1SignResponse = yuanZiService.verifyP1Sign(yuanZiVerifyP1SignRequest);
                    System.out.println(yuanZiVerifyP1SignResponse.getCode());
                    System.out.println(yuanZiVerifyP1SignResponse.getMessage());
                    //本地验签
                    boolean verify=false; 
                    signature.initVerify(publicKey); //使用公钥初始化签名对象,用于验证签名 
                    //原子
                    signature.update(dataToSign);
                    verify= signature.verify(dataHadSignature); //得到验证结果 
                    System.out.println("本地的验签结果:"+verify);
    
    
                } catch (Exception e) {
                    e.printStackTrace();
                    // TODO: handle exception
                }
    
            }

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P7签名:  
P7签名其实也就是P1签名的基础上,附加一些其他的信息(因为P1是裸签名,只有加密串,除了本人自己,根本不知道签名证书,公钥,签名算法,签名用的hash算法,时间戳,签名原文等等信息是什么,不便于验证签名,所以就需要有P7签名作为补充,其实也就是在P1之后,在加密串的基础上,附加这些信息上去)

所以我们在itextpdf的源码上能看到,其实它做签名的时候,也就是先构建出一个要签名的字符串,然后丢给某个私钥进行签名,获得签名值,它再对这个签名值附加:证书链,时间戳等等信息,然后构建出一个P7签名,然后放入PDF文件中.

PKCS\#1：定义RSA公开密钥算法加密和签名机制，主要用于组织PKCS\#7中所描述的数字签名和数字信封\[22\]。  
PKCS\#7：定义一种通用的消息语法，包括数字签名和加密等用于增强的加密机制，PKCS\#7与PEM兼容，所以不需其他密码操作，就可以将加密的消息转换成PEM消息\[26\]。