* add readme

* add .gitignore

* add keyinfo tool

* fix up makefile to build i2pd git submodule

keyinfo.cpp

@@ -0,0 +1,70 @@
+#include "Identity.h"
+#include <iostream>
+#include <fstream>
+#include <string>
+#include <vector>
+#include <unistd.h>
+
+int main(int argc, char * argv[])
+{
+  if(argc == 1) {
+    std::cout << "usage: " << argv[0] << " [-v] [-d] privatekey.dat" << std::endl;
+    return -1;
+  }
+  int opt;
+  bool print_full = false;
+  bool verbose = false;
+  while((opt = getopt(argc, argv, "vd"))!=-1) {
+    switch(opt){ 
+    case 'v':
+      verbose = true;
+      break;
+    case 'd':
+      print_full = true;
+      break;
+    default:
+      std::cout << "usage: " << argv[0] << " [-v] [-d] privatekey.dat" << std::endl;
+      return -1;
+    }
+  }
+  std::string fname(argv[optind]);
+  i2p::data::PrivateKeys keys;
+  {
+    std::vector<uint8_t> buff;
+    std::ifstream inf;
+    inf.open(fname);
+    if (!inf.is_open()) {
+      std::cout << "cannot open private key file " << fname << std::endl;
+      return 2;
+    }
+    inf.seekg(0, std::ios::end);
+    const std::size_t len = inf.tellg();
+    inf.seekg(0, std::ios::beg);
+    buff.resize(len);
+    inf.read((char*)buff.data(), buff.size());
+    if (!keys.FromBuffer(buff.data(), buff.size())) {
+      std::cout << "bad key file format" << std::endl;
+      return 3;
+    }
+  }
+  auto dest = keys.GetPublic();
+  if(!dest) {
+    std::cout << "failed to extract public key" << std::endl;
+    return 3;
+  }
+  
+  const auto & ident = dest->GetIdentHash();
+  if (verbose) {
+    std::cout << "Destination: " << dest->ToBase64() << std::endl;
+    std::cout << "Destination Hash: " << ident.ToBase64() << std::endl;
+    std::cout << "B32 Address: " << ident.ToBase32() << ".b32.i2p" << std::endl;
+    std::cout << "Signature Type: " << (int) dest->GetSigningKeyType() << std::endl;
+    std::cout << "Encryption Type: " << (int) dest->GetCryptoKeyType() << std::endl;
+  } else {
+    if(print_full) {
+      std::cout << dest->ToBase64() << std::endl;
+    } else {
+      std::cout << ident.ToBase32() << ".b32.i2p" << std::endl;
+    }
+  }
+}