Android 获取签名、公钥方法

private byte[] getSign(Context context) {
PackageManager pm = context.getPackageManager();
List<PackageInfo> apps = pm
.getInstalledPackages(PackageManager.GET_SIGNATURES);
Iterator<PackageInfo> iter = apps.iterator();

while (iter.hasNext()) {
PackageInfo info = iter.next();
String packageName = info.packageName;
//按包名 取签名
if (packageName.equals("com.test.test")) {
return info.signatures[0].toByteArray();

}
}
return null;
}

public static String getPublicKey(byte[] signature) {
try {

CertificateFactory certFactory = CertificateFactory
.getInstance("X.509");
X509Certificate cert = (X509Certificate) certFactory
.generateCertificate(new ByteArrayInputStream(signature));

String publickey = cert.getPublicKey().toString();
publickey = publickey.substring(publickey.indexOf("modulus: ") + 9,
publickey.indexOf("\n", publickey.indexOf("modulus:")));

Log.d("TRACK", publickey);
return publickey;
} catch (CertificateException e) {
e.printStackTrace();
}
return null;
}