diff --git a/idutils/__init__.py b/idutils/__init__.py
index 1d753b1..ca41371 100644
--- a/idutils/__init__.py
+++ b/idutils/__init__.py
@@ -384,6 +384,11 @@
 )
 """See https://www.wikidata.org/wiki/Property:P214."""
 
+email_regexp = re.compile(r"\S+@(\S+\.)+\S+")
+
+sha1_regexp = re.compile(r"^[a-fA-F0-9]{40}$")
+"""See https://www.w3.org/TR/annotation-model/#agents."""
+
 
 def _convert_x_to_10(x):
     """Convert char to int with X being converted to 10."""
@@ -698,6 +703,20 @@ def is_viaf(val):
         return False
 
 
+def is_email(val):
+    """Test if argument looks like an email address.
+
+    Note this test is designed to distinguish an email from other identifier
+    schemes only. It does not imply a valid address / domain etc.
+    """
+    return email_regexp.match(val)
+
+
+def is_sha1(val):
+    """Test if argument is a valid SHA-1 (hex) hash."""
+    return sha1_regexp.match(val)
+
+
 PID_SCHEMES = [
     ("doi", is_doi),
     ("ark", is_ark),
@@ -733,6 +752,8 @@ def is_viaf(val):
     ("arrayexpress_experiment", is_arrayexpress_experiment),
     ("swh", is_swh),
     ("viaf", is_viaf),
+    ("email", is_email),
+    ("sha1", is_sha1),
 ]
 """Definition of scheme name and associated test function.
 
@@ -979,11 +1000,14 @@ def normalize_pid(val, scheme):
     "genome": "{scheme}://www.ncbi.nlm.nih.gov/assembly/{pid}",
     "geo": "{scheme}://www.ncbi.nlm.nih.gov/geo/query/acc.cgi?acc={pid}",
     "arrayexpress_array": "{scheme}://www.ebi.ac.uk/arrayexpress/arrays/{pid}",
-    "arrayexpress_experiment": "{scheme}://www.ebi.ac.uk/arrayexpress/experiments/{pid}",
+    "arrayexpress_experiment": (
+        "{scheme}://www.ebi.ac.uk/arrayexpress/experiments/{pid}"
+    ),
     "hal": "{scheme}://hal.archives-ouvertes.fr/{pid}",
     "swh": "{scheme}://archive.softwareheritage.org/{pid}",
     "ror": "{scheme}://ror.org/{pid}",
     "viaf": "{scheme}://viaf.org/viaf/{pid}",
+    "email": "mailto:{pid}",
 }
 """URL generation configuration for the supported PID providers."""
 
diff --git a/tests/test_idutils.py b/tests/test_idutils.py
index 949d5e4..6866198 100644
--- a/tests/test_idutils.py
+++ b/tests/test_idutils.py
@@ -771,6 +771,18 @@
             ";origin=https://github.com/python/cpython"
         ),
     ),
+    (
+        "user1@example.com",
+        ["email"],
+        "user1@example.com",
+        "mailto:user1@example.com",
+    ),
+    (
+        "5b5056cbf89049064b44d5101764aaae42eb1447",
+        ["sha1"],
+        "5b5056cbf89049064b44d5101764aaae42eb1447",
+        "",
+    ),
 ]