diff --git a/api/tests/unit_tests/core/helper/test_encrypter.py b/api/tests/unit_tests/core/helper/test_encrypter.py
new file mode 100644
index 0000000000..61cf8f255d
--- /dev/null
+++ b/api/tests/unit_tests/core/helper/test_encrypter.py
@@ -0,0 +1,280 @@
+import base64
+import binascii
+from unittest.mock import MagicMock, patch
+
+import pytest
+
+from core.helper.encrypter import (
+    batch_decrypt_token,
+    decrypt_token,
+    encrypt_token,
+    get_decrypt_decoding,
+    obfuscated_token,
+)
+from libs.rsa import PrivkeyNotFoundError
+
+
+class TestObfuscatedToken:
+    @pytest.mark.parametrize(
+        ("token", "expected"),
+        [
+            ("", ""),  # Empty token
+            ("1234567", "*" * 20),  # Short token (<8 chars)
+            ("12345678", "*" * 20),  # Boundary case (8 chars)
+            ("123456789abcdef", "123456" + "*" * 12 + "ef"),  # Long token
+            ("abc!@#$%^&*()def", "abc!@#" + "*" * 12 + "ef"),  # Special chars
+        ],
+    )
+    def test_obfuscation_logic(self, token, expected):
+        """Test core obfuscation logic for various token lengths"""
+        assert obfuscated_token(token) == expected
+
+    def test_sensitive_data_protection(self):
+        """Ensure obfuscation never reveals full sensitive data"""
+        token = "api_key_secret_12345"
+        obfuscated = obfuscated_token(token)
+        assert token not in obfuscated
+        assert "*" * 12 in obfuscated
+
+
+class TestEncryptToken:
+    @patch("models.engine.db.session.query")
+    @patch("libs.rsa.encrypt")
+    def test_successful_encryption(self, mock_encrypt, mock_query):
+        """Test successful token encryption"""
+        mock_tenant = MagicMock()
+        mock_tenant.encrypt_public_key = "mock_public_key"
+        mock_query.return_value.filter.return_value.first.return_value = mock_tenant
+        mock_encrypt.return_value = b"encrypted_data"
+
+        result = encrypt_token("tenant-123", "test_token")
+
+        assert result == base64.b64encode(b"encrypted_data").decode()
+        mock_encrypt.assert_called_with("test_token", "mock_public_key")
+
+    @patch("models.engine.db.session.query")
+    def test_tenant_not_found(self, mock_query):
+        """Test error when tenant doesn't exist"""
+        mock_query.return_value.filter.return_value.first.return_value = None
+
+        with pytest.raises(ValueError) as exc_info:
+            encrypt_token("invalid-tenant", "test_token")
+
+        assert "Tenant with id invalid-tenant not found" in str(exc_info.value)
+
+
+class TestDecryptToken:
+    @patch("libs.rsa.decrypt")
+    def test_successful_decryption(self, mock_decrypt):
+        """Test successful token decryption"""
+        mock_decrypt.return_value = "decrypted_token"
+        encrypted_data = base64.b64encode(b"encrypted_data").decode()
+
+        result = decrypt_token("tenant-123", encrypted_data)
+
+        assert result == "decrypted_token"
+        mock_decrypt.assert_called_once_with(b"encrypted_data", "tenant-123")
+
+    def test_invalid_base64(self):
+        """Test handling of invalid base64 input"""
+        with pytest.raises(binascii.Error):
+            decrypt_token("tenant-123", "invalid_base64!!!")
+
+
+class TestBatchDecryptToken:
+    @patch("libs.rsa.get_decrypt_decoding")
+    @patch("libs.rsa.decrypt_token_with_decoding")
+    def test_batch_decryption(self, mock_decrypt_with_decoding, mock_get_decoding):
+        """Test batch decryption functionality"""
+        mock_rsa_key = MagicMock()
+        mock_cipher_rsa = MagicMock()
+        mock_get_decoding.return_value = (mock_rsa_key, mock_cipher_rsa)
+
+        # Test multiple tokens
+        mock_decrypt_with_decoding.side_effect = ["token1", "token2", "token3"]
+        tokens = [
+            base64.b64encode(b"encrypted1").decode(),
+            base64.b64encode(b"encrypted2").decode(),
+            base64.b64encode(b"encrypted3").decode(),
+        ]
+        result = batch_decrypt_token("tenant-123", tokens)
+
+        assert result == ["token1", "token2", "token3"]
+        # Key should only be loaded once
+        mock_get_decoding.assert_called_once_with("tenant-123")
+
+
+class TestGetDecryptDecoding:
+    @patch("extensions.ext_redis.redis_client.get")
+    @patch("extensions.ext_storage.storage.load")
+    def test_private_key_not_found(self, mock_storage_load, mock_redis_get):
+        """Test error when private key file doesn't exist"""
+        mock_redis_get.return_value = None
+        mock_storage_load.side_effect = FileNotFoundError()
+
+        with pytest.raises(PrivkeyNotFoundError) as exc_info:
+            get_decrypt_decoding("tenant-123")
+
+        assert "Private key not found, tenant_id: tenant-123" in str(exc_info.value)
+
+
+class TestEncryptDecryptIntegration:
+    @patch("models.engine.db.session.query")
+    @patch("libs.rsa.encrypt")
+    @patch("libs.rsa.decrypt")
+    def test_should_encrypt_and_decrypt_consistently(self, mock_decrypt, mock_encrypt, mock_query):
+        """Test that encryption and decryption are consistent"""
+        # Setup mock tenant
+        mock_tenant = MagicMock()
+        mock_tenant.encrypt_public_key = "mock_public_key"
+        mock_query.return_value.filter.return_value.first.return_value = mock_tenant
+
+        # Setup mock encryption/decryption
+        original_token = "test_token_123"
+        mock_encrypt.return_value = b"encrypted_data"
+        mock_decrypt.return_value = original_token
+
+        # Test encryption
+        encrypted = encrypt_token("tenant-123", original_token)
+
+        # Test decryption
+        decrypted = decrypt_token("tenant-123", encrypted)
+
+        assert decrypted == original_token
+
+
+class TestSecurity:
+    """Critical security tests for encryption system"""
+
+    @patch("models.engine.db.session.query")
+    @patch("libs.rsa.encrypt")
+    def test_cross_tenant_isolation(self, mock_encrypt, mock_query):
+        """Ensure tokens encrypted for one tenant cannot be used by another"""
+        # Setup mock tenant
+        mock_tenant = MagicMock()
+        mock_tenant.encrypt_public_key = "tenant1_public_key"
+        mock_query.return_value.filter.return_value.first.return_value = mock_tenant
+        mock_encrypt.return_value = b"encrypted_for_tenant1"
+
+        # Encrypt token for tenant1
+        encrypted = encrypt_token("tenant-123", "sensitive_data")
+
+        # Attempt to decrypt with different tenant should fail
+        with patch("libs.rsa.decrypt") as mock_decrypt:
+            mock_decrypt.side_effect = Exception("Invalid tenant key")
+
+            with pytest.raises(Exception, match="Invalid tenant key"):
+                decrypt_token("different-tenant", encrypted)
+
+    @patch("libs.rsa.decrypt")
+    def test_tampered_ciphertext_rejection(self, mock_decrypt):
+        """Detect and reject tampered ciphertext"""
+        valid_encrypted = base64.b64encode(b"valid_data").decode()
+
+        # Tamper with ciphertext
+        tampered_bytes = bytearray(base64.b64decode(valid_encrypted))
+        tampered_bytes[0] ^= 0xFF
+        tampered = base64.b64encode(bytes(tampered_bytes)).decode()
+
+        mock_decrypt.side_effect = Exception("Decryption error")
+
+        with pytest.raises(Exception, match="Decryption error"):
+            decrypt_token("tenant-123", tampered)
+
+    @patch("models.engine.db.session.query")
+    @patch("libs.rsa.encrypt")
+    def test_encryption_randomness(self, mock_encrypt, mock_query):
+        """Ensure same plaintext produces different ciphertext"""
+        mock_tenant = MagicMock(encrypt_public_key="key")
+        mock_query.return_value.filter.return_value.first.return_value = mock_tenant
+
+        # Different outputs for same input
+        mock_encrypt.side_effect = [b"enc1", b"enc2", b"enc3"]
+
+        results = [encrypt_token("tenant-123", "token") for _ in range(3)]
+
+        # All results should be different
+        assert len(set(results)) == 3
+
+
+class TestEdgeCases:
+    """Additional security-focused edge case tests"""
+
+    def test_should_handle_empty_string_in_obfuscation(self):
+        """Test handling of empty string in obfuscation"""
+        # Test empty string (which is a valid str type)
+        assert obfuscated_token("") == ""
+
+    @patch("models.engine.db.session.query")
+    @patch("libs.rsa.encrypt")
+    def test_should_handle_empty_token_encryption(self, mock_encrypt, mock_query):
+        """Test encryption of empty token"""
+        mock_tenant = MagicMock()
+        mock_tenant.encrypt_public_key = "mock_public_key"
+        mock_query.return_value.filter.return_value.first.return_value = mock_tenant
+        mock_encrypt.return_value = b"encrypted_empty"
+
+        result = encrypt_token("tenant-123", "")
+
+        assert result == base64.b64encode(b"encrypted_empty").decode()
+        mock_encrypt.assert_called_with("", "mock_public_key")
+
+    @patch("models.engine.db.session.query")
+    @patch("libs.rsa.encrypt")
+    def test_should_handle_special_characters_in_token(self, mock_encrypt, mock_query):
+        """Test tokens containing special/unicode characters"""
+        mock_tenant = MagicMock()
+        mock_tenant.encrypt_public_key = "mock_public_key"
+        mock_query.return_value.filter.return_value.first.return_value = mock_tenant
+        mock_encrypt.return_value = b"encrypted_special"
+
+        # Test various special characters
+        special_tokens = [
+            "token\x00with\x00null",  # Null bytes
+            "token_with_emoji_😀🎉",  # Unicode emoji
+            "token\nwith\nnewlines",  # Newlines
+            "token\twith\ttabs",  # Tabs
+            "token_with_中文字符",  # Chinese characters
+        ]
+
+        for token in special_tokens:
+            result = encrypt_token("tenant-123", token)
+            assert result == base64.b64encode(b"encrypted_special").decode()
+            mock_encrypt.assert_called_with(token, "mock_public_key")
+
+    @patch("models.engine.db.session.query")
+    @patch("libs.rsa.encrypt")
+    def test_should_handle_rsa_size_limits(self, mock_encrypt, mock_query):
+        """Test behavior when token exceeds RSA encryption limits"""
+        mock_tenant = MagicMock()
+        mock_tenant.encrypt_public_key = "mock_public_key"
+        mock_query.return_value.filter.return_value.first.return_value = mock_tenant
+
+        # RSA 2048-bit can only encrypt ~245 bytes
+        # The actual limit depends on padding scheme
+        mock_encrypt.side_effect = ValueError("Message too long for RSA key size")
+
+        # Create a token that would exceed RSA limits
+        long_token = "x" * 300
+
+        with pytest.raises(ValueError, match="Message too long for RSA key size"):
+            encrypt_token("tenant-123", long_token)
+
+    @patch("libs.rsa.get_decrypt_decoding")
+    @patch("libs.rsa.decrypt_token_with_decoding")
+    def test_batch_decrypt_loads_key_only_once(self, mock_decrypt_with_decoding, mock_get_decoding):
+        """Verify batch decryption optimization - loads key only once"""
+        mock_rsa_key = MagicMock()
+        mock_cipher_rsa = MagicMock()
+        mock_get_decoding.return_value = (mock_rsa_key, mock_cipher_rsa)
+
+        # Test with multiple tokens
+        mock_decrypt_with_decoding.side_effect = ["token1", "token2", "token3", "token4", "token5"]
+        tokens = [base64.b64encode(f"encrypted{i}".encode()).decode() for i in range(5)]
+
+        result = batch_decrypt_token("tenant-123", tokens)
+
+        assert result == ["token1", "token2", "token3", "token4", "token5"]
+        # Key should only be loaded once regardless of token count
+        mock_get_decoding.assert_called_once_with("tenant-123")
+        assert mock_decrypt_with_decoding.call_count == 5