我正在尝试使用bouncy castle在Android apk文件中阅读CERT.RSA的内容。
使用：openssl pkcs7 -inform DER -in CERT.RSA -noout -print_certs -text
我得到以下，这似乎是正确的：
Certificate:
Data:
Version: 3 (0x2)
Serial Number:
93:6e:ac:be:07:f2:01:df
Signature Algorithm: sha1WithRSAEncryption
Issuer: C=US, ST=California, L=Mountain View, O=Android, OU=Android, CN=Android/[email protected]
Validity
Not Before: Feb 29 01:33:46 2008 GMT
Not After : Jul 17 01:33:46 2035 GMT
Subject: C=US, ST=California, L=Mountain View, O=Android, OU=Android, CN=Android/[email protected]
Subject Public Key Info:
Public Key Algorithm: rsaEncryption
Public-Key: (2048 bit)
Modulus:
00:d6:93:19:04:de:c6:0b:24:b1:ed:c7:62:e0:d9:
d8:25:3e:3e:cd:6c:eb:1d:e2:ff:06:8c:a8:e8:bc:
a8:cd:6b:d3:78:6e:a7:0a:a7:6c:e6:0e:bb:0f:99:
35:59:ff:d9:3e:77:a9:43:e7:e8:3d:4b:64:b8:e4:
fe:a2:d3:e6:56:f1:e2:67:a8:1b:bf:b2:30:b5:78:
c2:04:43:be:4c:72:18:b8:46:f5:21:15:86:f0:38:
a1:4e:89:c2:be:38:7f:8e:be:cf:8f:ca:c3:da:1e:
e3:30:c9:ea:93:d0:a7:c3:dc:4a:f3:50:22:0d:50:
08:07:32:e0:80:97:17:ee:6a:05:33:59:e6:a6:94:
ec:2c:b3:f2:84:a0:a4:66:c8:7a:94:d8:3b:31:09:
3a:67:37:2e:2f:64:12:c0:6e:6d:42:f1:58:18:df:
fe:03:81:cc:0c:d4:44:da:6c:dd:c3:b8:24:58:19:
48:01:b3:25:64:13:4f:bf:de:98:c9:28:77:48:db:
f5:67:6a:54:0d:81:54:c8:bb:ca:07:b9:e2:47:55:
33:11:c4:6b:9a:f7:6f:de:ec:cc:8e:69:e7:c8:a2:
d0:8e:78:26:20:94:3f:99:72:7d:3c:04:fe:72:99:
1d:99:df:9b:ae:38:a0:b2:17:7f:a3:1d:5b:6a:fe:
e9:1f
Exponent: 3 (0x3)
X509v3 extensions:
X509v3 Subject Key Identifier:
48:59:00:56:3D:27:2C:46:AE:11:86:05:A4:74:19:AC:09:CA:8C:11
X509v3 Authority Key Identifier:
keyid:48:59:00:56:3D:27:2C:46:AE:11:86:05:A4:74:19:AC:09:CA:8C:11
DirName:/C=US/ST=California/L=Mountain View/O=Android/OU=Android/CN=Android/[email protected]
serial:93:6E:AC:BE:07:F2:01:DF
X509v3 Basic Constraints:
CA:TRUE
Signature Algorithm: sha1WithRSAEncryption
7a:af:96:8c:eb:50:c4:41:05:51:18:d0:da:ab:af:01:5b:8a:
76:5a:27:a7:15:a2:c2:b4:4f:22:14:15:ff:da:ce:03:09:5a:
bf:a4:2d:f7:07:08:72:6c:20:69:e5:c3:6e:dd:ae:04:00:be:
29:45:2c:08:4b:c2:7e:b6:a1:7e:ac:9d:be:18:2c:20:4e:b1:
53:11:f4:55:d8:24:b6:56:db:e4:dc:22:40:91:2d:75:86:fe:
88:95:1d:01:a8:fe:b5:ae:5a:42:60:53:5d:f8:34:31:05:24:
22:46:8c:36:e2:2c:2a:5e:f9:94:d6:1d:d7:30:6a:e4:c9:f6:
95:1b:a3:c1:2f:1d:19:14:dd:c6:1f:1a:62:da:2d:f8:27:f6:
03:fe:a5:60:3b:2c:54:0d:bd:7c:01:9c:36:ba:b2:9a:42:71:
c1:17:df:52:3c:db:c5:f3:81:7a:49:e0:ef:a6:0c:bd:7f:74:
17:7e:7a:4f:19:3d:43:f4:22:07:72:66:6e:4c:4d:83:e1:bd:
5a:86:08:7c:f3:4f:2d:ec:21:e2:45:ca:6c:2b:b0:16:e6:83:
63:80:50:d2:c4:30:ee:a7:c2:6a:1c:49:d3:76:0a:58:ab:7f:
1a:82:cc:93:8b:48:31:38:43:24:bd:04:01:fa:12:16:3a:50:
57:0e:68:4d
但是当我使用Bouncy Castle时，我没有得到公钥模数和其他必要的东西。 pubkey只是null。我想我在代码中犯了一些错误，但除了公钥之外，我得到了我想要的一切，这很奇怪。
X509CertParser certParser = new X509CertParser();
FileInputStream stream;
X509CertificateObject cert= null;
try {
stream = new FileInputStream("CERT.RSA");
certParser.engineInit(stream);
cert = (X509CertificateObject) certParser.engineRead();
stream.close();
if(cert.getPublicKey()==null)System.out.println("NULL");
} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
此代码打印NULL，而openssl调用告诉我模数等。
我该怎么做才能获得Java中的pubkey？ （也许有可能使用android sdk或其他东西来获取数据而不是充气城堡）
编辑：
我忘了提到我已经尝试了David Grants代码，它给出了错误消息，即DerInputStream太大了：
java.security.cert.CertificateException: Unable to initialize, java.io.IOException: DerInputStream.getLength(): lengthTag=127, too big.
at sun.security.x509.X509CertImpl.<init>(X509CertImpl.java:199)
at sun.security.provider.X509Factory.engineGenerateCertificate(X509Factory.java:107)
at java.security.cert.CertificateFactory.generateCertificate(CertificateFactory.java:322)
你不需要BC来从DER流中读取证书，你可以在Java SE中做得很好：
InputStream in = new FileInputStream("CERT.RSA");
CertificateFactory factory = CertificateFactory.getInstance("X.509")
X509Certificate cert = (X509Certificate) factory.generateCertificate(in);
如果你开始使用BouncyCastle，你可以尝试使用PEMReader类。 （显然，您的证书需要采用PEM格式，而不是DER）。
FileReader fileReader = new FileReader("/path/to/cert.pem");
PEMReader pemReader = new PEMReader(fileReader);
Object obj = pemReader.readObject();
pemReader.close(); // sloppy IO handling, be thorough in production code
X509CertificateObject certObj = (X509CertificateObject) obj;
System.out.println(certObj.getPublicKey());
出于某种原因，您发布的代码不会泄露公钥。我不知道为什么。
您可以使用CERT.RSA方法阅读PKCS7文件：
PKCS7 p7 = new PKCS7(new FileInputStream("CERT.RSA"));
p7.getCertificates();
这将返回一个X509Certificate数组。
在Android中，您可以使用digital certificate抽象类来读取包的X509Certificate（META-INF / CERT.RSA）的内容。
final String appPackage = "com.example" // TODO: Add here the package name!!
try {
final PackageManager pm = getPackageManager();
final ApplicationInfo ai = pm.getApplicationInfo(appPackage, PackageManager.GET_META_DATA);
if ( ai != null ) {
final PackageInfo pi = pm.getPackageInfo(this.packageName, PackageManager.GET_PERMISSIONS);
if ( pi != null ) {
final Signature[] signatures = pi.signatures;
if ( (pi.signatures != null) && (pi.signatures.length > 0) ) {
for ( final Signature signature : signatures ) {
if ( signature != null ) {
final InputStream certInputStream = new ByteArrayInputStream(signature.toByteArray());
final CertificateFactory certFactory;
final X509Certificate x509Cert;
try {
certFactory = CertificateFactory.getInstance("X509");
if ( certFactory != null ) {
x509Cert = (X509Certificate) certFactory.generateCertificate(certInputStream);
if ( x509Cert != null ) {
SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
Log.d(TAG, "Certificate Owner: " + x509Cert.getSubjectDN().toString());
Log.d(TAG, "Certificate Issuer: " + x509Cert.getIssuerDN().toString());
Log.d(TAG, "Certificate Serial Number: " + x509Cert.getSerialNumber().toString());
Log.d(TAG, "Certificate Algorithm: " + x509Cert.getSigAlgName());
Log.d(TAG, "Certificate Version: " + x509Cert.getVersion());
Log.d(TAG, "Certificate OID: " + x509Cert.getSigAlgOID());
Log.d(TAG, "Certificate Valid From: " + dateFormat.format( x509Cert.getNotBefore() ));
Log.d(TAG, "Certificate Valid To: " + dateFormat.format( x509Cert.getNotAfter() ));
try {
final MessageDigest md = MessageDigest.getInstance("SHA-256");
md.update( x509Cert.getEncoded() );
Log.d(TAG, "Certificate SHA-256: " + getHex(md.digest()));
}
catch ( NoSuchAlgorithmException e ) {
//Debug:
Log.e(TAG, "MessageDigest ERROR: " + e.getMessage() + "\n");
//e.printStackTrace();
}
}
}
}
catch ( final CertificateException e ) {
//Debug:
Log.e(TAG, "CertificateFactory ERROR: " + e.getMessage() + "\n");
//e.printStackTrace();
}
}
}
}
}
}
}
catch ( final PackageManager.NameNotFoundException e ) {
//Debug:
Log.e(TAG, "ApplicationInfo ERROR: " + e.getMessage() + "\n");
//e.printStackTrace();
}
用于提取数字证书的SHA-256哈希的getHex（）方法如下：
/**
* Get the hex value of a raw byte array.
*
* @param raw the raw byte array.
* @return the hex value.
*/
public static String getHex( byte[] raw ) {
final String HEXES = "0123456789abcdef";
if ( (raw == null) || (raw.length == 0) ) {
return null;
}
final StringBuilder hex = new StringBuilder( 2 * raw.length );
for ( final byte b : raw ) {
hex.append(HEXES.charAt((b & 0xF0) >> 4)).append(HEXES.charAt((b & 0x0F)));
}
return hex.toString();
}
此外，您可以提取所有者和发行者字段的所有条目（分别使用getSubjectDN()和getIssuerDN()的X509Certificate方法检索），当它们为非null时，例如，使用以下代码：
for ( final String field : (x509Cert.getSubjectDN().toString()).split(", ") ) {
if ( field.startsWith("CN=") ) {
Log.d(TAG, "Common Name: " + field.substring(3));
}
if ( field.startsWith("OU=") ) {
Log.d(TAG, "Organization Unit: " + field.substring(3));
}
if ( field.startsWith("O=") ) {
Log.d(TAG, "Organization name: " + field.substring(2));
}
if ( field.startsWith("L=") ) {
Log.d(TAG, "Locality name: " + field.substring(2));
}
if ( field.startsWith("ST=") ) {
Log.d(TAG, "State or province Name: " + field.substring(3));
}
if ( field.startsWith("C=") ) {
Log.d(TAG, "Country: " + field.substring(2));
}
if ( field.startsWith("DC=") ) {
Log.d(TAG, "Domain Component: " + field.substring(3));
}
}