diff --git a/src/lib.rs b/src/lib.rs
index dde929a486ffaa11a28c48b7d04e6053db78c508..3d0c220065c01c9f3ee4e9d3c17337de7e3dd1e3 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -1254,12 +1254,7 @@ ffi!(fn _pgp_generate_keypair(session: *mut Session,
     let session = Session::as_mut(session)?;
     let mm = session.mm();
 
-    let identity = if let Some(i) = PepIdentity::as_mut(identity) {
-        i
-    } else {
-        return Err(Error::IllegalValue(
-            "identity must not be NULL".into()));
-    };
+    let identity = PepIdentity::as_mut(identity)?;
     t!("identity: {:?}", identity);
 
     let is_group_identity
diff --git a/src/pep/identity.rs b/src/pep/identity.rs
index bbc7a42b3e8fda1591761aebaa914b89dca6c4d9..522846740e3ca1ebc8c4dddb0f3d35733657e822 100644
--- a/src/pep/identity.rs
+++ b/src/pep/identity.rs
@@ -34,6 +34,8 @@ use std::ptr;
 use sequoia_openpgp as openpgp;
 use openpgp::Fingerprint;
 
+use crate::Error;
+use crate::Result;
 use crate::buffer::{
     malloc_cleared,
     rust_str_to_c_str,
@@ -118,8 +120,13 @@ impl PepIdentity {
     /// Converts the raw pointer to a Rust reference.
     ///
     /// This does not take ownership of the object.
-    pub fn as_mut(ptr: *mut Self) -> Option<&'static mut Self> {
-        unsafe { ptr.as_mut() }
+    pub fn as_mut(ptr: *mut Self) -> Result<&'static mut Self> {
+        if let Some(identity) = unsafe { ptr.as_mut() } {
+            Ok(identity)
+        } else {
+            Err(Error::IllegalValue(
+                "PepIdentity may not be NULL".into()))
+        }
     }
 
     /// Returns the address.