如何从java中的公钥生成一个tor服务洋葱地址？

Question

我正在尝试生成从公钥生成的洋葱地址。

如果在previous post 中的代码中添加以下行，就在 privateKeyEncoded

之后

String publicKeyEncoded = encoder.encodeToString(publicKey.getEncoded());

当我将 privateKeyEncoded 放入 /var/lib/tor/hidden_​​service/private_key 时，保存 publicKeyEncoded 并启动 tor 服务，创建一个新的洋葱地址。我正在尝试获取与 tor 服务相同的洋葱地址，以及从 publicKeyEncoded 创建的地址。使用此代码

import org.apache.commons.codec.binary.Base32;
import org.apache.commons.codec.binary.Base64;

//base64 string from the public key created
String publicKeyTest = "MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQCMnFkJTMZ2ZxnqLwCiB/EWHjsHbnC+sKEIrGbyOTYiTl3LygsekAX6LhgcllscLUFqSKlMRB3jRB0GAPrIc73E/hTnmWBtF8NT8DhZzl06LZ1BtNjfON1pHm87STMAayiSaXPmSOwIqOA89aJPcA9m4v4IhtjYSFXmCAsE4RqoAwIDAQAB";
//the onion address the tor service gives when the private key is used
String onionAddressTest = "qqkhrc4men3fiqyl";

byte[] publicKeyDecoded = Base64.decodeBase64(publicKeyTest);
MessageDigest messageDigest = MessageDigest.getInstance("SHA-1");
byte[] sha1hash = messageDigest.digest(publicKeyDecoded);
int numberOfCharacters = 10;
byte[] reducedHash = new byte[numberOfCharacters];
for(int i = 0; i < numberOfCharacters; i++) {
    reducedHash[i] = sha1hash[i];
}
Base32 base32encoder = new Base32();
String onionAddress = base32encoder.encodeAsString(reducedHash).toLowerCase();
System.out.println(onionAddress);  // but this gives "7j3iz4of464hje2e"

我尝试使用spongycastle 复制我的转换，但得到了相同的答案。这让我觉得我生成公钥的方式有问题，或者我从 base64 进行的初始转换有问题。

给定公钥 (publicKeyTest) 如何使用 java 获取洋葱地址 (onionAddressTest)？

Answer 1

根据this 和this，您需要仅对 Java 使用的 X.509 SubjectPublicKeyInfo 编码的偏移量 22 开始的部分进行散列处理，该编码称为“X.509”，并通过OpenSSL 将其称为“PUBKEY”。我在这方面找不到任何实际的 Tor 文档，但我不认为这正是 RSA-1024 密钥的 SPKI 格式的算法相关数据的开始：

$ openssl asn1parse -i <49833260.b64
    0:d=0  hl=3 l= 159 cons: SEQUENCE
    3:d=1  hl=2 l=  13 cons:  SEQUENCE
    5:d=2  hl=2 l=   9 prim:   OBJECT            :rsaEncryption
   16:d=2  hl=2 l=   0 prim:   NULL
   18:d=1  hl=3 l= 141 prim:  BIT STRING
# 18 +3 for DER tag+len +1 for unusedbitcount in BITSTRING = 22
# and the content beginning at 22 is:
$ openssl asn1parse -i -strparse 22 <49833260.b64
    0:d=0  hl=3 l= 137 cons: SEQUENCE
    3:d=1  hl=3 l= 129 prim:  INTEGER           :8C9C59094CC6766719EA2F00A207F11
61E3B076E70BEB0A108AC66F23936224E5DCBCA0B1E9005FA2E181C965B1C2D416A48A94C441DE34
41D0600FAC873BDC4FE14E799606D17C353F03859CE5D3A2D9D41B4D8DF38DD691E6F3B4933006B2
8926973E648EC08A8E03CF5A24F700F66E2FE0886D8D84855E6080B04E11AA803
  135:d=1  hl=2 l=   3 prim:  INTEGER           :010001
# which is (exactly) the RSAPublicKey structure from PKCS1

因此，要在 Java 中执行此操作，您可以假设 RSA-1024，或者使用 BouncyCastle（我假设，但尚未测试，海绵堡），您实际上可以正确解析 ASN.1：

byte[] pubkeyder = Base64.decode("MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQCMnFkJTMZ2ZxnqLwCiB/EWHjsHbnC+sKEIrGbyOTYiTl3LygsekAX6LhgcllscLUFqSKlMRB3jRB0GAPrIc73E/hTnmWBtF8NT8DhZzl06LZ1BtNjfON1pHm87STMAayiSaXPmSOwIqOA89aJPcA9m4v4IhtjYSFXmCAsE4RqoAwIDAQAB");
MessageDigest sha1 = MessageDigest.getInstance("SHA1");
// method 1
byte[] x1 = sha1.digest (Arrays.copyOfRange(pubkeyder, 22, pubkeyder.length));
System.out.println (new String(b32enc(Arrays.copyOf(x1,10))).toLowerCase());
// method 2
byte[] x2 = sha1.digest (SubjectPublicKeyInfo.getInstance(pubkeyder).getPublicKeyData().getOctets());
System.out.println (new String(b32enc(Arrays.copyOf(x2,10))).toLowerCase());
-> 
qqkhrc4men3fiqyl
qqkhrc4men3fiqyl