Merge pull request #167 from skalenetwork/enhancement/SKALE-4723-add-…

…MAGIC_STRING Enhancement/skale 4723 add magic string
skalenetwork · Nov 11, 2021 · ff286fc · ff286fc
2 parents 385f1f3 + f1b9bc3
commit ff286fc
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Showing 5 changed files with 61 additions and 8 deletions.
diff --git a/node/encryptTransaction.js b/node/encryptTransaction.js
@@ -50,4 +50,6 @@ async function encryptAndSend(eth, to, data) {
 }
 
 
-module.exports.encryptAndSend = encryptAndSend
+module.exports.encryptAndSend = encryptAndSend
+module.exports.encrypt_data = encrypt_data
+module.exports.get_common_bls_public_key = get_common_bls_public_key
diff --git a/test/unit_tests_te.cpp b/test/unit_tests_te.cpp
@@ -195,6 +195,48 @@ BOOST_AUTO_TEST_CASE( ConvertionToStringAndBack ) {
     BOOST_REQUIRE( ciphertext_with_aes == ciphertext_from_string );
 }
 
+BOOST_AUTO_TEST_CASE( ConvertionToStringAndBackWrongMagicString ) {
+    libBLS::ThresholdUtils::initCurve();
+
+    std::string message =
+        "Hello, SKALE users and fans, gl!Hello, SKALE users and fans, gl!";  // message should be 64
+                                                                             // length
+
+    libff::alt_bn128_Fr secret_key = libff::alt_bn128_Fr::random_element();
+
+    libff::alt_bn128_G2 public_key = secret_key * libff::alt_bn128_G2::one();
+
+    auto ciphertext_with_aes = libBLS::TE::encryptWithAES( message, public_key );
+
+    auto str =
+        libBLS::TE::aesCiphertextToString( ciphertext_with_aes.first, ciphertext_with_aes.second );
+
+    auto ciphertext_from_string = libBLS::TE::aesCiphertextFromString( str );
+
+    std::string random_bytes = "ff7e0d516baae0301df502d886ed08bb";
+
+    str = random_bytes + str.substr( 32, std::string::npos );
+
+    // auto V_old = std::get< 1 >( ciphertext_with_aes.first );
+    // auto V_new = std::get< 1 >( ciphertext_from_string.first );
+
+    // auto W_old = std::get< 2 >( ciphertext_with_aes.first );
+    // auto W_new = std::get< 2 >( ciphertext_from_string.first );
+
+    // auto U_old = std::get< 0 >( ciphertext_with_aes.first );
+    // auto U_new = std::get< 0 >( ciphertext_from_string.first );
+
+    // BOOST_REQUIRE( U_old == U_new );
+    // BOOST_REQUIRE( W_old == W_new );
+    // BOOST_REQUIRE( V_old == V_new );
+    // BOOST_REQUIRE( ciphertext_with_aes.first == ciphertext_from_string.first );
+    // BOOST_REQUIRE( ciphertext_with_aes.second.size() == ciphertext_from_string.second.size() );
+    // BOOST_REQUIRE( ciphertext_with_aes == ciphertext_from_string );
+
+    BOOST_REQUIRE_THROW(
+        libBLS::TE::aesCiphertextFromString( str ), libBLS::ThresholdUtils::IncorrectInput );
+}
+
 BOOST_AUTO_TEST_CASE( ConvertionToStringAndBackTooShort ) {
     libBLS::ThresholdUtils::initCurve();
 

diff --git a/threshold_encryption/threshold_encryption.cpp b/threshold_encryption/threshold_encryption.cpp
@@ -33,6 +33,8 @@
 
 namespace libBLS {
 
+const std::string TE::MAGIC_STRING = "8b1ba8JdPjeWd4G0bFRB0KBohPCULTHN";
+
 TE::TE( const size_t t, const size_t n ) : t_( t ), n_( n ) {
     libff::init_alt_bn128_params();
     libff::inhibit_profiling_info = true;
@@ -309,15 +311,21 @@ std::string TE::aesCiphertextToString(
 
     std::string w_str = x + y;
 
-    return u_str + v_str + w_str + encrypted_data;
+    return MAGIC_STRING + u_str + v_str + w_str + encrypted_data;
 }
 
 std::pair< Ciphertext, std::vector< uint8_t > > TE::aesCiphertextFromString(
     const std::string& str ) {
     ThresholdUtils::initCurve();
     ThresholdUtils::initAES();
 
-    if ( !ThresholdUtils::checkHex( str ) ) {
+    if ( str.substr( 0, 32 ) != MAGIC_STRING ) {
+        throw ThresholdUtils::IncorrectInput(
+            "Provided input was not encrypted properly: MAGIC_STRING doesn't match" );
+    }
+
+    std::string ciphertext = str.substr( 32, std::string::npos );
+    if ( !ThresholdUtils::checkHex( ciphertext ) ) {
         throw ThresholdUtils::IncorrectInput( "Provided string contains non-hex symbols" );
     }
 
@@ -326,11 +334,11 @@ std::pair< Ciphertext, std::vector< uint8_t > > TE::aesCiphertextFromString(
             "Incoming string is too short to convert to aes ciphertext" );
     }
 
-    std::string u_str = str.substr( 0, 256 );
-    std::string v_str = str.substr( 256, 128 );
-    std::string w_str = str.substr( 256 + 128, 128 );
+    std::string u_str = ciphertext.substr( 0, 256 );
+    std::string v_str = ciphertext.substr( 256, 128 );
+    std::string w_str = ciphertext.substr( 256 + 128, 128 );
 
-    std::string encrypted_data = str.substr( 256 + 128 + 128, std::string::npos );
+    std::string encrypted_data = ciphertext.substr( 256 + 128 + 128, std::string::npos );
 
     uint64_t bin_len;
     std::vector< uint8_t > aes_cipher( encrypted_data.size() / 2 );

diff --git a/threshold_encryption/threshold_encryption.h b/threshold_encryption/threshold_encryption.h
@@ -74,6 +74,8 @@ class TE {
     static std::pair< Ciphertext, std::vector< uint8_t > > aesCiphertextFromString(
         const std::string& str );
 
+    static const std::string MAGIC_STRING;
+
 private:
     const size_t t_ = 0;
 

diff --git a/tools/utils.cpp b/tools/utils.cpp
@@ -365,7 +365,6 @@ std::vector< uint8_t > ThresholdUtils::aesEncrypt(
 
     int actual_size = 0, final_size = 0;
     EVP_CIPHER_CTX* e_ctx = EVP_CIPHER_CTX_new();
-    // EVP_CIPHER_CTX_ctrl(e_ctx, EVP_CTRL_GCM_SET_IVLEN, 16, NULL);
     EVP_EncryptInit( e_ctx, EVP_aes_256_gcm(), ( const unsigned char* ) key.c_str(), iv );
     EVP_EncryptUpdate( e_ctx, &output[64], &actual_size, ( const unsigned char* ) plaintext.data(),
         plaintext.length() );