使用JAVA数字证书做数字签名认证
1.
keytool -genkey -keystore chinajavaworld.keystore -alias chinajavaworld
这个命令用来产生一个密匙库，执行完毕后会在当前操作目录中产生一个chinajavaworld.keystore的文件，在执行命令的时候还有提示你输入密匙库的密码，要记住，后面还要用到。
2.
keytool -export -keystore chinajavaworld.keystore -alias chinajavaworld -file chinajavaworld.cer
这个命令用来产生签名时所要用的证书。
3.在JAVA里操作，将Cer内容改为BASE64编码
//从密钥库中读取CA证书String storepass = "123456";//前面设置的密码FileInputStream in = new FileInputStream("e:\\license\\a\\chinajavaworld.keystore");KeyStore ks = KeyStore.getInstance("JKS");ks.load(in, storepass.toCharArray());//获取证书java.security.cert.Certificate c1 = ks.getCertificate("chinajavaworld");//BASE64编码System.out.println(StringUtils.encodeBase64(c1.getEncoded()));//将chinajavaworld.cer内容改为这里输出的内容 Signature signature; try { InputStream streamCert = new java.io.FileInputStream( "e:\\license\\a\\test.cer"); CertificateFactory factory = CertificateFactory.getInstance("X.509"); Certificate cert = factory.generateCertificate(streamCert); System.out.println(StringUtils.encodeBase64(cert.getEncoded())); signature = Signature.getInstance("SHA1withDSA"); signature.initVerify(cert.getPublicKey()); //要签名的指纹内容 String sss = "Welcome to www.chinajavaworld.com,The java world for you forever."; //获取CA证书私钥 PrivateKey priKey=(PrivateKey)ks.getKey("test",storepass.toCharArray()); System.out.println("priKey:"+StringUtils.encodeHex(priKey.getEncoded())); //用私钥签名 sig = Signature.getInstance("SHA1withDSA"); sig.initSign(priKey); ByteArrayOutputStream streamRaw0 = new ByteArrayOutputStream(); DataOutputStream streamSig0 = new DataOutputStream(streamRaw0); streamSig0.writeUTF(sss); sig.update(streamRaw0.toByteArray()); String signatureS = StringUtils.encodeHex(sig.sign()); System.out.println("signature: "+signatureS); //用公钥做验证测试 System.out.println("pubKey:"+StringUtils.encodeHex(cert.getPublicKey().getEncoded())); ByteArrayOutputStream streamRaw = new ByteArrayOutputStream(); DataOutputStream streamSig = new DataOutputStream(streamRaw); streamSig.writeUTF(sss); signature.update(streamRaw.toByteArray()); System.out.println("verify: "+signature.verify(StringUtils.decodeHex(signatureS))); } catch(Exception e) { System.out.println(e); }public static String encodeBase64(byte data[]) { boolean lineSep = false; int sLen = data == null ? 0 : data.length; if(sLen == 0) return new String(""); int eLen = (sLen / 3) * 3; int cCnt = (sLen - 1) / 3 + 1 << 2; int dLen = cCnt + (lineSep ? (cCnt - 1) / 76 << 1 : 0); char dArr[] = new char[dLen]; int s = 0; int d = 0; int cc = 0; do { if(s >= eLen) break; int i = (data[s++] & 0xff) << 16 | (data[s++] & 0xff) << 8 | data[s++] & 0xff; dArr[d++] = CA[i >>> 18 & 0x3f]; dArr[d++] = CA[i >>> 12 & 0x3f]; dArr[d++] = CA[i >>> 6 & 0x3f]; dArr[d++] = CA[i & 0x3f]; if(lineSep && ++cc == 19 && d < dLen - 2) { dArr[d++] = '\r'; dArr[d++] = '\n'; cc = 0; } } while(true); int left = sLen - eLen; if(left > 0) { int i = (data[eLen] & 0xff) << 10 | (left != 2 ? 0 : (data[sLen - 1] & 0xff) << 2); dArr[dLen - 4] = CA[i >> 12]; dArr[dLen - 3] = CA[i >>> 6 & 0x3f]; dArr[dLen - 2] = left != 2 ? '=' : CA[i & 0x3f]; dArr[dLen - 1] = '='; } return new String(dArr); } public static final String encodeHex(byte bytes[]) { StringBuffer buf = new StringBuffer(bytes.length * 2); for(int i = 0; i < bytes.length; i++) { if((bytes[i] & 0xff) < 16) buf.append("0"); buf.append(Long.toString(bytes[i] & 0xff, 16)); } return buf.toString(); } public static final byte[] decodeHex(String hex) { char chars[] = hex.toCharArray(); byte bytes[] = new byte[chars.length / 2]; int byteCount = 0; for(int i = 0; i < chars.length; i += 2) { int newByte = 0; newByte |= hexCharToByte(chars[i]); newByte <<= 4; newByte |= hexCharToByte(chars[i + 1]); bytes[byteCount] = (byte)newByte; byteCount++; } return bytes; }