diff --git a/src/domain.rs b/src/domain.rs
index 6e6c7ca..77ff766 100644
--- a/src/domain.rs
+++ b/src/domain.rs
@@ -4,6 +4,8 @@ use thiserror::Error;
 pub enum DomainError {
     #[error("database error: {0}")]
     Database(String),
+    #[error("password error: {0}")]
+    Password(String),
     #[error("record not found")]
     NotFound,
     #[error("record already exists")]
diff --git a/src/ports.rs b/src/ports.rs
index 48395ec..549815e 100644
--- a/src/ports.rs
+++ b/src/ports.rs
@@ -128,8 +128,8 @@ pub trait InvitationRepository: Send + Sync {
 
 #[async_trait]
 pub trait PasswordHasher: Send + Sync {
-    fn hash(&self, password: &str) -> Result<String, String>;
-    fn verify(&self, password: &str, encoded_hash: &str) -> Result<bool, String>;
+    fn hash(&self, password: &str) -> DomainResult<String>;
+    fn verify(&self, password: &str, encoded_hash: &str) -> DomainResult<bool>;
 }
 
 #[async_trait]
diff --git a/src/security.rs b/src/security.rs
index 30bff36..422871a 100644
--- a/src/security.rs
+++ b/src/security.rs
@@ -8,22 +8,24 @@ use argon2::{
 use async_trait::async_trait;
 use rand::RngCore;
 
+use crate::domain::{DomainError, DomainResult};
 use crate::ports::{PasswordHasher, TokenGenerator};
 
 pub struct Argon2PasswordHasher;
 
 #[async_trait]
 impl PasswordHasher for Argon2PasswordHasher {
-    fn hash(&self, password: &str) -> Result<String, String> {
+    fn hash(&self, password: &str) -> DomainResult<String> {
         let salt = SaltString::generate(&mut OsRng);
         Argon2::default()
             .hash_password(password.as_bytes(), &salt)
             .map(|hash| hash.to_string())
-            .map_err(|error| error.to_string())
+            .map_err(|error| DomainError::Password(error.to_string()))
     }
 
-    fn verify(&self, password: &str, encoded_hash: &str) -> Result<bool, String> {
-        let hash = PasswordHash::new(encoded_hash).map_err(|error| error.to_string())?;
+    fn verify(&self, password: &str, encoded_hash: &str) -> DomainResult<bool> {
+        let hash = PasswordHash::new(encoded_hash)
+            .map_err(|error| DomainError::Password(error.to_string()))?;
         Ok(Argon2::default()
             .verify_password(password.as_bytes(), &hash)
             .is_ok())
diff --git a/src/services.rs b/src/services.rs
index 09db85a..d801efe 100644
--- a/src/services.rs
+++ b/src/services.rs
@@ -73,7 +73,7 @@ impl AuthService {
         if !self.can_register(invite).await? {
             return Err(DomainError::Conflict);
         }
-        let password_hash = self.hasher.hash(&password).map_err(DomainError::Database)?;
+        let password_hash = self.hasher.hash(&password)?;
         let users = Arc::clone(&self.users);
         let sessions = Arc::clone(&self.sessions);
         self.db
@@ -104,9 +104,7 @@ impl AuthService {
                     else {
                         return Ok(None);
                     };
-                    let valid = hasher
-                        .verify(&password, &password_hash)
-                        .map_err(DomainError::Database)?;
+                    let valid = hasher.verify(&password, &password_hash)?;
                     if !valid {
                         return Ok(None);
                     }