如何使用 BouncyCastle 从字符串生成私钥

Question

我有一个字符串存储在一个变量中：

我将 public 密钥生成为：

public static PublicKey getFromString(String keystr) throws Exception
{
  //String S1= asciiToHex(keystr);
   byte[] keyBytes = new sun.misc.BASE64Decoder().decodeBuffer(keystr);
   ASN1InputStream in = new ASN1InputStream(keyBytes);
   DERObject obj = in.readObject();
   RSAPublicKeyStructure pStruct = RSAPublicKeyStructure.getInstance(obj);
   RSAPublicKeySpec spec = new RSAPublicKeySpec(pStrcut.getModulus(), pStruct.getPublicExponent());
   KeyFactory kf = KeyFactory.getInstance("RSA");
   return kf.generatePublic(spec);
}

如何在android中使用充气城堡生成私钥

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在不使用充气城堡的情况下，我生成的私钥是这样的：

public static PrivateKey getKey(String mKey){
        try{
            // Read in the key into a String
            StringBuilder pkcs8Lines = new StringBuilder();
            BufferedReader rdr = new BufferedReader(new StringReader(mKey));
            String line;
            while ((line = rdr.readLine()) != null) {
                pkcs8Lines.append(line);
            }

            // Remove the "BEGIN" and "END" lines, as well as any whitespace

            String pkcs8Pem = pkcs8Lines.toString();
            pkcs8Pem = pkcs8Pem.replace("-----BEGIN RSA PRIVATE KEY-----", "");
            pkcs8Pem = pkcs8Pem.replace("-----END RSA PRIVATE KEY-----", "");
            pkcs8Pem = pkcs8Pem.replaceAll("\s+","");

            // Base64 decode the result

            byte [] pkcs8EncodedBytes = Base64.decode(pkcs8Pem, Base64.DEFAULT);

            // extract the private key

            PKCS8EncodedKeySpec keySpec = new PKCS8EncodedKeySpec(pkcs8EncodedBytes);
            KeyFactory kf = KeyFactory.getInstance("RSA");
            PrivateKey privKey = kf.generatePrivate(keySpec);
            System.out.println(privKey);

            return privKey;
        }catch (Exception ex){
            ex.printStackTrace();
        }
        return null;
    }

我想用 Bouncy Castle 达到同样的效果

Answer 1

我对您为什么坚持使用 bouncycastle 感到有点困惑，但如果您真的想使用 bouncycastle，那么 CMS/PKIX 库有一个很好的助手 class，名为 PEMParser这将缩短所需的代码，例如：

public static PrivateKey getPemPrivateKey(String mKey) throws Exception {
    PEMParser pemParser = new PEMParser(new StringReader(mKey));
    final PEMKeyPair pemKeyPair = (PEMKeyPair) pemParser.readObject();
    final byte[] encoded = pemKeyPair.getPrivateKeyInfo().getEncoded();
    KeyFactory kf = KeyFactory.getInstance("RSA");
    return kf.generatePrivate(new PKCS8EncodedKeySpec(encoded));

}

如何使用 BouncyCastle 从字符串生成私钥

How to generate Private key from string using BouncyCastle

java

android

bouncycastle

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