Question

我目前能够使用此代码从cer文件读取密钥模数，也可以在StackOverflow上找到：

X509Certificate cert = null;
String source = "src/testCer.cer";
InputStream fis = null;                 
ByteArrayInputStream bais = null;               


fis = new FileInputStream(source);              
byte value[] = new byte[fis.available()];       
fis.read(value);                                
bais = new ByteArrayInputStream(value);             
java.security.cert.CertificateFactory cf = java.security.cert.CertificateFactory.getInstance("X.509");
cert = (X509Certificate)cf.generateCertificate(bais);    
RSAPublicKey pub = (RSAPublicKey) cert.getPublicKey();

System.out.println(pub.getModulus());

.cer文件如下所示:(证书是在互联网上找到的Alice证书示例）：

一个很好的Base64编码包装文本。

我的问题：

如何将此证书保存到字符串，并使用该证书而不是从文件中读取证书？

到目前为止，我试过了：

String cert_1= "-----BEGIN CERTIFICATE-----"
                + "MIIBuTCCASKgAwIBAgIQNdNhtuV5GbNHYZsf+LvM0zANBgkqhkiG9w0BAQUFADAb"
                + "MRkwFwYDVQQDExBFZGlkZXYgU21va2VUZXN0MB4XDTA4MTExMjE5NTEzNVoXDTM5"
                + "MTIzMTIzNTk1OVowGzEZMBcGA1UEAxMQRWRpZGV2IFNtb2tlVGVzdDCBnzANBgkq"
                + "hkiG9w0BAQEFAAOBjQAwgYkCgYEAm6zGzqxejwswWTNLcSsa7P8xqODspX9VQBuq"
                + "CBpT4S5AaO3/wkYQSKdI108pXH7Aue0e/ZOwgEEX1N6OaPQn7AmAB4uq1h+ffw+r"
                + "5W1RoTgQ0LNR64+7ywLjH8+wrb/lB6QV7s2SFUiWDeduVesvMJkWtZ5zzQyl3iUa"
                + "RKNHqnsCAwEAATANBgkqhkiG9w0BAQUFAAOBgQCZmj+pgRsN6HpoICawK3XXNAmi"
                + "cgfQkailX9akIjD3xSCwEQx4nG6tZjTz30u4NoSffW7pch58SxuZQDqW5NsJcQNq"
                + "Ngo/dMoqqpXdi2/0BYEcJ8pjsngrFm+fM2BnyGpXH7aWuKsWjVFGlWlF+yi8I35Q"
                + "8wFJt2Z/XGA7WWDjvw=="
                + "-----END CERTIFICATE-----";

    fis = new ByteArrayInputStream(cert_1.getBytes());

导致错误： java.io.IOException：数据不完整。

fis.available也与从文件加载的证书不同。（它短2）。我猜这与包裹有关。我怀疑这是因为如果在记事本中看到第一行上没有单独的Header，则.cer文件不起作用，但确实有效。

Answer 1

问题是你的字符串文字没有任何换行符。要忠实地代表原始文本，您需要：

String cert_1= "-----BEGIN CERTIFICATE-----\n"
    + "MIIBuTCCASKgAwIBAgIQNdNhtuV5GbNHYZsf+LvM0zANBgkqhkiG9w0BAQUFADAb\n"
    + "MRkwFwYDVQQDExBFZGlkZXYgU21va2VUZXN0MB4XDTA4MTExMjE5NTEzNVoXDTM5\n"
    + "MTIzMTIzNTk1OVowGzEZMBcGA1UEAxMQRWRpZGV2IFNtb2tlVGVzdDCBnzANBgkq\n"
    + "hkiG9w0BAQEFAAOBjQAwgYkCgYEAm6zGzqxejwswWTNLcSsa7P8xqODspX9VQBuq\n"
    + "CBpT4S5AaO3/wkYQSKdI108pXH7Aue0e/ZOwgEEX1N6OaPQn7AmAB4uq1h+ffw+r\n"
    + "5W1RoTgQ0LNR64+7ywLjH8+wrb/lB6QV7s2SFUiWDeduVesvMJkWtZ5zzQyl3iUa\n"
    + "RKNHqnsCAwEAATANBgkqhkiG9w0BAQUFAAOBgQCZmj+pgRsN6HpoICawK3XXNAmi\n"
    + "cgfQkailX9akIjD3xSCwEQx4nG6tZjTz30u4NoSffW7pch58SxuZQDqW5NsJcQNq\n"
    + "Ngo/dMoqqpXdi2/0BYEcJ8pjsngrFm+fM2BnyGpXH7aWuKsWjVFGlWlF+yi8I35Q\n"
    + "8wFJt2Z/XGA7WWDjvw==\n"
    + "-----END CERTIFICATE-----";

...但你可能只是确保BEGIN CERTIFICATE和END CERTIFICATE标记在他们自己的行上，这样你就可以逃脱：

String cert_1= "-----BEGIN CERTIFICATE-----\n"
    + "MIIBuTCCASKgAwIBAgIQNdNhtuV5GbNHYZsf+LvM0zANBgkqhkiG9w0BAQUFADAb"
    + "MRkwFwYDVQQDExBFZGlkZXYgU21va2VUZXN0MB4XDTA4MTExMjE5NTEzNVoXDTM5"
    + "MTIzMTIzNTk1OVowGzEZMBcGA1UEAxMQRWRpZGV2IFNtb2tlVGVzdDCBnzANBgkq"
    + "hkiG9w0BAQEFAAOBjQAwgYkCgYEAm6zGzqxejwswWTNLcSsa7P8xqODspX9VQBuq"
    + "CBpT4S5AaO3/wkYQSKdI108pXH7Aue0e/ZOwgEEX1N6OaPQn7AmAB4uq1h+ffw+r"
    + "5W1RoTgQ0LNR64+7ywLjH8+wrb/lB6QV7s2SFUiWDeduVesvMJkWtZ5zzQyl3iUa"
    + "RKNHqnsCAwEAATANBgkqhkiG9w0BAQUFAAOBgQCZmj+pgRsN6HpoICawK3XXNAmi"
    + "cgfQkailX9akIjD3xSCwEQx4nG6tZjTz30u4NoSffW7pch58SxuZQDqW5NsJcQNq"
    + "Ngo/dMoqqpXdi2/0BYEcJ8pjsngrFm+fM2BnyGpXH7aWuKsWjVFGlWlF+yi8I35Q"
    + "8wFJt2Z/XGA7WWDjvw==\n"
    + "-----END CERTIFICATE-----";

我还建议您在文本和二进制数据之间进行转换时明确指定字符集：

fis = new ByteArrayInputStream(cert_1.getBytes(StandardCharsets.UTF_8));

将Base64编码的CER文件保存为String

1 个答案: