diff --git a/earthsnake/identity.py b/earthsnake/identity.py
index a1cbef3..eff8a09 100644
--- a/earthsnake/identity.py
+++ b/earthsnake/identity.py
@@ -4,7 +4,7 @@ import re
 from typing import Optional
 
 import bip39
-from ed25519 import SigningKey, VerifyingKey, create_keypair
+from ed25519 import BadSignatureError, SigningKey, VerifyingKey, create_keypair
 
 from .base32 import base32_bytes_to_string, base32_string_to_bytes
 from .exc import ValidationError
@@ -23,8 +23,8 @@ class Identity:
 
     _KEY_PATTERN = f'b[{B32_CHAR}]{{52}}'
     _NAME_PATTERN = f'[{ALPHA_LOWER}][{ALPHA_LOWER_OR_DIGIT}]{{3}}'
-    _PATTERN = f'^@{_NAME_PATTERN}\\.{_KEY_PATTERN}$'
     _SECRET_PATTERN = f'^{_KEY_PATTERN}$'
+    PATTERN = f'^@{_NAME_PATTERN}\\.{_KEY_PATTERN}$'
 
     def __init__(
         self,
@@ -143,3 +143,23 @@ class Identity:
         mnemonic = bip39.encode_bytes(seed)
 
         return f'{self.name} {mnemonic}'
+
+    def sign(self, data: str) -> str:
+        """Sign data"""
+
+        if not self.sign_key:
+            raise TypeError('This identity doesn’t have a signing key')
+
+        return base32_bytes_to_string(self.sign_key.sign(data.encode('utf-8')))
+
+    def verify(self, data: str, signature: str) -> bool:
+        """Verify if data is signed by us"""
+
+        signature_bytes = base32_string_to_bytes(signature)
+
+        try:
+            self.verify_key.verify(signature_bytes, data.encode('utf-8'))
+        except BadSignatureError:
+            return False
+
+        return True
diff --git a/tests/test_identity.py b/tests/test_identity.py
index 3e51953..e6dfd64 100644
--- a/tests/test_identity.py
+++ b/tests/test_identity.py
@@ -199,3 +199,56 @@ def test_eq_other(identity: Identity) -> None:
 
     with pytest.raises(TypeError):
         assert identity == 1
+
+
+def test_sign_nokey() -> None:
+    """Test if Identity.sign() fails if the identity doesn’t have a signing key available"""
+
+    identity_str = '@test.bcz76z52y5dlpohtkmpuj3jsdcvfmebzpcgfmtmhu4u7hlexzreya'
+    identity = Identity.from_address(identity_str)
+
+    with pytest.raises(TypeError):
+        identity.sign('test data')
+
+
+@pytest.mark.id_key_seed(TEST_SEED)
+@pytest.mark.id_name('test')
+def test_sign(identity: Identity) -> None:
+    """Test if Identity.sign() works as expected"""
+
+    assert (
+        identity.sign('test data')
+        == 'b6gyis42cvdfhsp7xx3jb4773ebbqoq4zhdo4pyeitskefrfkkzxwdkwjkjpq2oyglpngx4tpzzezeedp7eb'
+        'x4i3vkpq7wj6odjinacy'
+    )
+
+
+@pytest.mark.id_key_seed(TEST_SEED)
+@pytest.mark.id_name('test')
+def test_verify(identity: Identity) -> None:
+    """Test if Identity.verify works as expected"""
+
+    assert (
+        identity.verify(
+            'test data',
+            'b6gyis42cvdfhsp7xx3jb4773ebbqoq4zhdo4pyeitskefrfkkzxwdkwjkjpq2oyglpngx4tpzzezeedp7eb'
+            'x4i3vkpq7wj6odjinacy',
+        )
+        is True
+    )
+    assert (
+        identity.verify(
+            'test date',
+            'b6gyis42cvdfhsp7xx3jb4773ebbqoq4zhdo4pyeitskefrfkkzxwdkwjkjpq2oyglpngx4tpzzezeedp7eb'
+            'x4i3vkpq7wj6odjinacy',
+        )
+        is False
+    )
+    assert (
+        identity.verify(
+            'test data',
+            'b6gyis42cvdfhsp7xx3jb4773ebbqoq4zhdo4pyeitskefrfkkzxwdkwjkjpq2oyglpngx4tpzzezeedp7eb'
+            'x4i3vkpq7wj6odjinacq',
+        )
+        is False
+    )