diff --git a/pass/Controllers/AdvancedSettingsTableViewController.swift b/pass/Controllers/AdvancedSettingsTableViewController.swift
index a775b79..43e772e 100644
--- a/pass/Controllers/AdvancedSettingsTableViewController.swift
+++ b/pass/Controllers/AdvancedSettingsTableViewController.swift
@@ -35,8 +35,8 @@ class AdvancedSettingsTableViewController: UITableViewController {
     }
 
     private func setGitSignatureText() {
-        let gitSignatureName = passwordStore.gitSignatureForNow.name!
-        let gitSignatureEmail = passwordStore.gitSignatureForNow.email!
+        let gitSignatureName = passwordStore.gitSignatureForNow?.name ?? ""
+        let gitSignatureEmail = passwordStore.gitSignatureForNow?.email ?? ""
         self.gitSignatureTableViewCell.detailTextLabel?.font = UIFont.systemFont(ofSize: 14)
         self.gitSignatureTableViewCell.detailTextLabel?.text = "\(gitSignatureName) <\(gitSignatureEmail)>"
         if SharedDefaults[.gitSignatureName] == nil && SharedDefaults[.gitSignatureEmail] == nil {
diff --git a/pass/Controllers/GitConfigSettingTableViewController.swift b/pass/Controllers/GitConfigSettingTableViewController.swift
index a9713fd..f074e26 100644
--- a/pass/Controllers/GitConfigSettingTableViewController.swift
+++ b/pass/Controllers/GitConfigSettingTableViewController.swift
@@ -21,8 +21,8 @@ class GitConfigSettingTableViewController: UITableViewController {
         tableView.rowHeight = UITableView.automaticDimension
 
         let signature = passwordStore.gitSignatureForNow
-        nameTextField.placeholder = signature.name
-        emailTextField.placeholder = signature.email
+        nameTextField.placeholder = signature?.name ?? ""
+        emailTextField.placeholder = signature?.email ?? ""
         nameTextField.text = SharedDefaults[.gitSignatureName]
         emailTextField.text = SharedDefaults[.gitSignatureEmail]
     }
diff --git a/passKit/Helpers/AppError.swift b/passKit/Helpers/AppError.swift
index 03f2240..0bfd694 100644
--- a/passKit/Helpers/AppError.swift
+++ b/passKit/Helpers/AppError.swift
@@ -13,9 +13,12 @@ public enum AppError: Error {
     case KeyImport
     case PasswordDuplicated
     case GitReset
+    case GitCommit
+    case PasswordEntity
     case PgpPublicKeyNotExist
     case WrongPasswordFilename
     case Decryption
+    case Encryption
     case Unknown
 }
 
diff --git a/passKit/Models/PasswordEntity.swift b/passKit/Models/PasswordEntity.swift
index 8e5f4ce..e1ec0f7 100644
--- a/passKit/Models/PasswordEntity.swift
+++ b/passKit/Models/PasswordEntity.swift
@@ -33,11 +33,11 @@ extension PasswordEntity {
         return passwordCategoryArray
     }
 
-    public func getURL() -> URL? {
-        if let p = getPath().stringByAddingPercentEncodingForRFC3986() {
-            return URL(string: p)
+    public func getURL() throws -> URL {
+        if let p = getPath().stringByAddingPercentEncodingForRFC3986(), let u = URL(string: p) {
+            return u
         }
-        return nil
+        throw AppError.Unknown
     }
 
     // XXX: define some getters to get core data, we need to consider
diff --git a/passKit/Models/PasswordStore.swift b/passKit/Models/PasswordStore.swift
index bcf223f..e027648 100644
--- a/passKit/Models/PasswordStore.swift
+++ b/passKit/Models/PasswordStore.swift
@@ -30,11 +30,7 @@ public class PasswordStore {
     public var pgpKeyID: String?
     public var publicKey: GopenpgpwrapperKey? {
         didSet {
-            if publicKey != nil {
-                pgpKeyID = publicKey!.getID()
-            } else {
-                pgpKeyID = nil
-            }
+            pgpKeyID = publicKey?.getID()
         }
     }
     public var privateKey: GopenpgpwrapperKey?
@@ -42,14 +38,14 @@ public class PasswordStore {
         case PUBLIC, PRIVATE
     }
     
-    public var gitSignatureForNow: GTSignature {
+    public var gitSignatureForNow: GTSignature? {
         get {
             let gitSignatureName = SharedDefaults[.gitSignatureName] ?? Globals.gitSignatureDefaultName
             let gitSignatureEmail = SharedDefaults[.gitSignatureEmail] ?? Globals.gitSignatureDefaultEmail
-            return GTSignature(name: gitSignatureName, email: gitSignatureEmail, time: Date())!
+            return GTSignature(name: gitSignatureName, email: gitSignatureEmail, time: Date())
         }
     }
-    
+
     public var pgpKeyPassphrase: String? {
         set {
             Utils.addPasswordToKeychain(name: "pgpKeyPassphrase", password: newValue)
@@ -557,7 +553,9 @@ public class PasswordStore {
         let commitEnum = try GTEnumerator(repository: storeRepository)
         try commitEnum.pushSHA(headReference.targetOID!.sha)
         let parent = commitEnum.nextObject() as! GTCommit
-        let signature = gitSignatureForNow
+        guard let signature = gitSignatureForNow else {
+            throw AppError.GitCommit
+        }
         let commit = try storeRepository.createCommit(with: newTree, message: message, author: signature, committer: signature, parents: [parent], updatingReferenceNamed: headReference.name)
         return commit
     }
@@ -652,7 +650,7 @@ public class PasswordStore {
     }
     
     public func delete(passwordEntity: PasswordEntity) throws {
-        let deletedFileURL = passwordEntity.getURL()!
+        let deletedFileURL = try passwordEntity.getURL()
         try gitRm(path: deletedFileURL.path)
         try deletePasswordEntities(passwordEntity: passwordEntity)
         try deleteDirectoryTree(at: deletedFileURL)
@@ -662,18 +660,19 @@ public class PasswordStore {
     
     public func edit(passwordEntity: PasswordEntity, password: Password) throws -> PasswordEntity? {
         var newPasswordEntity: PasswordEntity? = passwordEntity
+        let url = try passwordEntity.getURL()
         
         if password.changed&PasswordChange.content.rawValue != 0 {
-            let saveURL = storeURL.appendingPathComponent(passwordEntity.getURL()!.path)
+            let saveURL = storeURL.appendingPathComponent(url.path)
             try self.encrypt(password: password).write(to: saveURL)
-            try gitAdd(path: passwordEntity.getURL()!.path)
-            let _ = try gitCommit(message: "EditPassword.".localize(passwordEntity.getURL()!.deletingPathExtension().path.removingPercentEncoding!))
+            try gitAdd(path: saveURL.path)
+            let _ = try gitCommit(message: "EditPassword.".localize(url.deletingPathExtension().path.removingPercentEncoding!))
             newPasswordEntity = passwordEntity
             newPasswordEntity?.synced = false
         }
         
         if password.changed&PasswordChange.path.rawValue != 0 {
-            let deletedFileURL = passwordEntity.getURL()!
+            let deletedFileURL = url
             // add
             try createDirectoryTree(at: password.url)
             newPasswordEntity = try addPasswordEntities(password: password)
@@ -823,11 +822,11 @@ public class PasswordStore {
         if passphrase == nil {
             passphrase = requestPGPKeyPassphrase()
         }
-        let decryptedData = privateKey?.decrypt(encryptedData, passphrase: passphrase)
-        let plainText = String(data: decryptedData!, encoding: .utf8) ?? ""
-        guard let url = passwordEntity.getURL() else {
+        guard let decryptedData = privateKey?.decrypt(encryptedData, passphrase: passphrase) else {
             throw AppError.Decryption
         }
+        let plainText = String(data: decryptedData, encoding: .utf8) ?? ""
+        let url = try passwordEntity.getURL()
         return Password(name: passwordEntity.getName(), url: url, plainText: plainText)
     }
     
@@ -836,9 +835,11 @@ public class PasswordStore {
             throw AppError.PgpPublicKeyNotExist
         }
         let plainData = password.plainData
-        let encryptedData = publicKey?.encrypt(plainData, armor: SharedDefaults[.encryptInArmored])
+        guard let encryptedData = publicKey?.encrypt(plainData, armor: SharedDefaults[.encryptInArmored]) else {
+            throw AppError.Encryption
+        }
         
-        return encryptedData!
+        return encryptedData
     }
     
     public func removePGPKeys() {