Java以编程方式从密钥/证书读取信息

我正在尝试构建一个证书/密钥管理工具，但我不知道如何获取证书/密钥的md5指纹

例如，如果我对密钥库使用keytool命令，我将获得

Keystore type: JKS
Keystore provider: SUN

Your keystore contains 1 entry

Alias name: myname
Creation date: 21-Aug-2011
Entry type: PrivateKeyEntry
Certificate chain length: 1
Certificate[1]:
Owner: CN=bla bla, L=bla, ST=bla
Issuer: CN=bla bla, L=bla, ST=bla
Serial number: 123w3qa
Valid from: Sun Aug 21 00:12:31 CEST 2011 until: Mon Jul 28 00:12:31 CEST 2110
Certificate fingerprints:
         MD5:  1A:DE:60:21:DE:B1:BF:C3:D1:AD:11:F1:21:22:D7:9E
         SHA1: 72:3A:D9:2E:1A:DE:60:21:DE:B1:BF:C3:D1:AD:11:F1:21:22:D7:9E
         Signature algorithm name: SHA256withRSA
         Version: 3

Extensions:

#1: ObjectId: 2.5.29.14 Criticality=false
SubjectKeyIdentifier [
KeyIdentifier [
0000: AA EA FA FE 34 DA 6E C6   FC 8B 6C DE S9 21 S9 S4  ......^...l.I!.D
0010: S3 33 29 SD                                        .S..
]
]

*******************************************
*******************************************

现在我想通过java获得以下信息： 1.MD5指纹 2.键标识符

我使用X500证书对象和X500主体获得了一些信息（例如日期从和到、所有者、颁发者、别名），但我没有找到可以获得其他信息的地方。有人能帮我吗

如果您检查钥匙工具的

keytool

，您可以看到以下内容：

 2830       getCertFingerPrint("MD5", cert),

这要求：

 3167       /**
 3168        * Gets the requested finger print of the certificate.
 3169        */
 3170       private String getCertFingerPrint(String mdAlg, Certificate cert)
 3171           throws Exception
 3172       {
 3173           byte[] encCertInfo = cert.getEncoded();
 3174           MessageDigest md = MessageDigest.getInstance(mdAlg);
 3175           byte[] digest = md.digest(encCertInfo);
 3176           return toHexString(digest);
 3177       }

---

您可以尝试以下代码-

  // Load the JDK's cacerts keystore file
            String filename = System.getProperty("java.home") + "/lib/security/cacerts".replace('/', File.separatorChar);

            FileInputStream is = new FileInputStream(filename);
            KeyStore keystore = KeyStore.getInstance(KeyStore.getDefaultType());
            String password = "changeit";
            keystore.load(is, password.toCharArray());

            // This class retrieves the most-trusted CAs from the keystore
            PKIXParameters params = new PKIXParameters(keystore);

            // Get the set of trust anchors, which contain the most-trusted CA certificates
            Iterator it = params.getTrustAnchors().iterator();
            while( it.hasNext() ) {
                TrustAnchor ta = (TrustAnchor)it.next();
                // Get certificate
                X509Certificate cert = ta.getTrustedCert();
                System.out.println(cert);
            }

---

我通过

keytool

找到了这个（DNA答案的扩展版）：

String filename=“密钥库的路径”；
String keyPassword=“您的密钥密码”；
String keyalis=“您的密钥别名”；
FileInputStream is=新的FileInputStream（文件名）；
KeyStore KeyStore=KeyStore.getInstance（KeyStore.getDefaultType（））；
load（is，keyPassword.toCharArray（））；
/*获取请求的证书指纹*/
X509Certificate cert=keystore.getCertificate（keyAlias）；
字节[]encCertInfo=cert.getEncoded（）；
MessageDigest md=MessageDigest.getInstance（“MD5”）；
字节[]摘要=md.digest（encCertInfo）；
/*将字节数组转换为十六进制字符串*/
StringBuffer buf=新的StringBuffer（）；
int len=摘要长度；
对于（int i=0；i>4）；
int低=（摘要[i]&0x0f）；
buf.append（六角字符[高]）；
buf.append（hexChars[low]）；
如果（i

---

我在安卓系统上测试过，效果很好。

你可以试着看看

keytool

本身的源代码吗？是的，你说得对，昨天我看了源代码，但没看到：(

String filename = "path to your keystore";
String keyPassword = "your key password";
String keyAlias = "your key alias";

FileInputStream is = new FileInputStream(filename);

KeyStore keystore = KeyStore.getInstance(KeyStore.getDefaultType());

keystore.load(is, keyPassword.toCharArray());

/* Gets the requested finger print of the certificate. */
X509Certificate cert = keystore.getCertificate(keyAlias);
byte[] encCertInfo = cert.getEncoded();
MessageDigest md = MessageDigest.getInstance("MD5");
byte[] digest = md.digest(encCertInfo);

/* Converts a byte array to hex string */
StringBuffer buf = new StringBuffer();
int len = digest.length;
for (int i = 0; i < len; i++) {
    /* Converts a byte to hex digit and writes to the supplied buffer */
    char[] hexChars = [ '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F' ];
    int high = ((digest[i] & 0xf0) >> 4);
    int low = (digest[i] & 0x0f);
    buf.append(hexChars[high]);
    buf.append(hexChars[low]);

    if (i < len-1) {
        buf.append(":");
    }
}

String your_md5_fingerprint = buf.toString();