我正在开发一个基于客户端服务器的应用程序。
我以字符串形式获取公钥,格式如下图所示: 现在我想在我的Android(Java代码)中使用这个密钥,该怎么做?
我以字符串形式获取公钥,格式如下图所示: 现在我想在我的Android(Java代码)中使用这个密钥,该怎么做?
首先,您需要从提供的pem格式生成公钥。以下是我完成此操作的方法:
/**
*
* @param PEMString -A file/string in .pem format with a generated RSA key (with "des3", using "openssl genrsa".)
* @param isFilePath - If it's a file path or a string
* @return java.security.PublicKey
* @throws IOException -No key found
* @throws NoSuchAlgorithmException
* @throws InvalidKeySpecException
*
* @author hsigmond
*/
private static PublicKey getPublicKeyFromPemFormat(String PEMString,
boolean isFilePath) throws IOException, NoSuchAlgorithmException,
InvalidKeySpecException {
BufferedReader pemReader = null;
if (isFilePath) {
pemReader = new BufferedReader(new InputStreamReader(
new FileInputStream(PEMString)));
} else {
pemReader = new BufferedReader(new InputStreamReader(
new ByteArrayInputStream(PEMString.getBytes("UTF-8"))));
}
StringBuffer content = new StringBuffer();
String line = null;
while ((line = pemReader.readLine()) != null) {
if (line.indexOf("-----BEGIN PUBLIC KEY-----") != -1) {
while ((line = pemReader.readLine()) != null) {
if (line.indexOf("-----END PUBLIC KEY") != -1) {
break;
}
content.append(line.trim());
}
break;
}
}
if (line == null) {
throw new IOException("PUBLIC KEY" + " not found");
}
Log.i("PUBLIC KEY: ", "PEM content = : " + content.toString());
KeyFactory keyFactory = KeyFactory.getInstance("RSA");
return keyFactory.generatePublic(new X509EncodedKeySpec(Base64.decode(content.toString(), Base64.DEFAULT)));
}
以下是我使用它来读取(解码)提供的公钥签名内容的方法。
/**
*
* @param PEMString -A file/string in .pem format with a generated RSA key (with "des3", using "openssl genrsa".)
* @param content
* @return String value of content Decoded
* @throws NoSuchAlgorithmException
* @throws InvalidKeySpecException
* @throws IOException
* @throws NoSuchProviderException
* @throws NoSuchPaddingException
* @throws InvalidKeyException
* @throws IllegalBlockSizeException
* @throws BadPaddingException
*
* @author hsigmond
*/
public static String getContentWithPublicKeyFromPemFormat(String PEMString,
String content,boolean isFilePath) throws NoSuchAlgorithmException,
InvalidKeySpecException, IOException, NoSuchProviderException,
NoSuchPaddingException, InvalidKeyException,
IllegalBlockSizeException, BadPaddingException {
PublicKey publicKey = getPublicKeyFromPemFormat(PEMString,isFilePath);
if (publicKey != null)
Log.i("PUBLIC KEY: ", "FORMAT : " + publicKey.getFormat()
+ " \ntoString : " + publicKey.toString());
byte[] contentBytes = Base64.decode(content, Base64.DEFAULT);
byte[] decoded = null;
Cipher cipher = Cipher.getInstance("RSA/ECB/PKCS1Padding", "BC");//BC=BouncyCastle Provider
cipher.init(Cipher.DECRYPT_MODE, publicKey);
decoded = cipher.doFinal(contentBytes);
return new String(decoded, "UTF-8");
}
有一个名为“bouncycastle”的项目,我们在j2me上使用它,但它也可以在Android上工作。它可以用来处理openssl证书。
Java KeyStore 实现:
import java.security.cert.Certificate import java.security.KeyStore
并且请务必阅读 readme,因为 OpenSSL 密钥不被 Java 直接支持,Java 有自己的机制。
KeyStore 的 Java 示例:
byte[] certData = ...
/* create KeyStore */
KeyStore ks = KeyStore.getInstance("JKS", "SUN");
/* load key store (initialization */
ks.load(null, null);
/* create CertificateFactory */
CertificateFactory cf = CertificateFactory.getInstance("X509");
/* create certificate from input stream */
Certificate cert;
/* provide cert data */
ByteArrayInputStream in = new ByteArrayInputStream(makeCert(certData));
private static byte[] makeCert(byte[] data) {
String headline = "-----BEGIN CERTIFICATE-----";
String footline = "-----END CERTIFICATE-----";
String certStr = headline;
for (int i = 0; i < data.length; i++) {
if (i%64 == 0) {
certStr += "\n";
}
certStr += (char)data[i];
}
if ((data.length-1)%64 != 0) {
certStr += "\n";
}
certStr += footline;
return certStr.getBytes();
}