push source

1 files changed, 82 insertions, 0 deletions

diff --git a/backend/chat-reader.cjs b/backend/chat-reader.cjs
new file mode 100644
index 0000000..e30e7c9
--- /dev/null
+++ b/backend/chat-reader.cjs
@@ -0,0 +1,82 @@
+const fs = require('fs');
+const crypto = require('crypto');
+
+function jwt_secret() {
+  let file = fs.readFileSync( '../data/jwt_secret.txt', 'utf8' );
+  if( file.endsWith( '\n' ) ) {
+    file = file.slice( 0, -1 );
+  }
+
+  return file;
+}
+
+function write( content, filename ) {
+  const chatJson = content;
+
+  const salt = crypto.randomBytes( 16 );
+  const key = crypto.pbkdf2Sync( jwt_secret(), salt, 100000, 32, 'sha512' );
+  const iv = crypto.randomBytes( 12 );
+
+  const cipher = crypto.createCipheriv( 'aes-256-gcm', key, iv );
+  let encrypted = cipher.update( chatJson, 'utf8', 'hex' );
+  encrypted += cipher.final( 'hex' );
+  const authTag = cipher.getAuthTag().toString( 'hex' );
+
+  let fullStr = salt.toString( 'hex' ) + iv.toString( 'hex' ) + authTag + encrypted;
+
+  fs.writeFileSync( filename, fullStr );
+}
+
+function read( filename ) {
+  let contents = '';
+  try {
+    contents = fs.readFileSync( filename, 'utf8' );
+  } catch( e ) {
+    console.log( '0' );
+    return;
+  }
+  const salt = Buffer.from( contents.slice( 0, 32 ), 'hex' );
+  const iv = Buffer.from( contents.slice( 32, 56 ), 'hex' );
+  const authTag = Buffer.from( contents.slice( 56, 88 ), 'hex' );
+  const data = contents.slice( 88 );
+
+  const key = crypto.pbkdf2Sync( jwt_secret(), salt, 100000, 32, 'sha512' );
+  const decipher = crypto.createDecipheriv( 'aes-256-gcm', key, iv );
+  decipher.setAuthTag( authTag );
+
+  let decrypted = decipher.update( data, 'hex', 'utf8' );
+  decrypted += decipher.final( 'utf8' );
+
+  return decrypted;
+}
+
+function main() {
+  const args = process.argv.slice(2);
+  const operation = args[0];
+
+  switch( operation ) {
+    case 'read': {
+      try {
+        const data = read( args[1] );
+        console.log( JSON.parse( JSON.stringify( data ) ) );
+      } catch( e ) {
+        console.log( "0" );
+        console.log( e.message );
+      }
+      break;
+    }
+    case 'write': {
+      try {
+        const data = args[2];
+        write( data, args[1] );
+        console.log( "1" );
+      } catch( e ) {
+        console.log( "0" );
+        console.log( e.message );
+      }
+      break;
+    }
+  }
+}
+
+main();