diff --git a/TrustKit/Pinning/TSKSPKIHashCache.h b/TrustKit/Pinning/TSKSPKIHashCache.h
index 5ed19da2..f0395fa1 100644
--- a/TrustKit/Pinning/TSKSPKIHashCache.h
+++ b/TrustKit/Pinning/TSKSPKIHashCache.h
@@ -30,13 +30,12 @@ typedef NSMutableDictionary<NSData *, NSData *> SPKICacheDictionnary;
 
 /**
  Create a new cache of SPKI hashes. The identifier is required to ensure that multiple cache
- instances do not attempt to use the same file on disk for persistence. If nil, persistence
- will be disabled (not recommended).
+ instances do not attempt to use the same file on disk for persistence.
 
  @param uniqueIdentifier A unique identifier that is stable across app launches/instance creation
  @return An initialized hash cache.
  */
-- (instancetype _Nullable)initWithIdentifier:(NSString * _Nullable)uniqueIdentifier NS_DESIGNATED_INITIALIZER;
+- (instancetype _Nullable)initWithIdentifier:(NSString*)uniqueIdentifier NS_DESIGNATED_INITIALIZER;
 
 /**
  Get a pin cache for the provided certificate and public key algorithm. The pins
diff --git a/TrustKit/Pinning/TSKSPKIHashCache.m b/TrustKit/Pinning/TSKSPKIHashCache.m
index 8cf8f2c4..7b267f34 100644
--- a/TrustKit/Pinning/TSKSPKIHashCache.m
+++ b/TrustKit/Pinning/TSKSPKIHashCache.m
@@ -116,7 +116,9 @@ - (instancetype)initWithIdentifier:(NSString *)uniqueIdentifier
         // Initialize our locks
         _lockQueue = dispatch_queue_create("TSKSPKIHashLock", DISPATCH_QUEUE_CONCURRENT);
 
-        _spkiCacheFilename = uniqueIdentifier; // if this value is nil, persistence will always fail.
+        // Ensure a non-nil identifier was provided
+        NSAssert(uniqueIdentifier, @"TSKSPKIHashCache initializer must be passed a unique identifier");
+        _spkiCacheFilename = uniqueIdentifier;
         
         // First try to load a cached version from the filesystem
         _subjectPublicKeyInfoHashesCache = [self loadSPKICacheFromFileSystem];
@@ -278,10 +280,6 @@ - (NSData *)getPublicKeyDataFromCertificate:(SecCertificateRef)certificate
 
 - (NSURL *)SPKICachePath
 {
-    if (!self.spkiCacheFilename)
-    {
-        return nil;
-    }
     NSURL *cachesDirUrl = [NSFileManager.defaultManager URLsForDirectory:NSCachesDirectory
                                                                inDomains:NSUserDomainMask].firstObject;
     return [cachesDirUrl URLByAppendingPathComponent:self.spkiCacheFilename];
diff --git a/TrustKitTests/TSKPublicKeyAlgorithmTests.m b/TrustKitTests/TSKPublicKeyAlgorithmTests.m
index 1a10726a..00891275 100644
--- a/TrustKitTests/TSKPublicKeyAlgorithmTests.m
+++ b/TrustKitTests/TSKPublicKeyAlgorithmTests.m
@@ -32,24 +32,19 @@ @interface TSKPublicKeyAlgorithmTests : XCTestCase
 @implementation TSKPublicKeyAlgorithmTests
 {
     TSKSPKIHashCache *spkiCache;
-    TSKSPKIHashCache *nonPersistentSpkiCache;
 }
 
 - (void)setUp
 {
     [super setUp];
     [spkiCache resetSubjectPublicKeyInfoDiskCache];
-    [nonPersistentSpkiCache resetSubjectPublicKeyInfoDiskCache];
     spkiCache = [[TSKSPKIHashCache alloc] initWithIdentifier:@"test"];
-    nonPersistentSpkiCache = [[TSKSPKIHashCache alloc] initWithIdentifier:nil];
 }
 
 - (void)tearDown
 {
     [spkiCache resetSubjectPublicKeyInfoDiskCache];
-    [nonPersistentSpkiCache resetSubjectPublicKeyInfoDiskCache];
     spkiCache = nil;
-    nonPersistentSpkiCache = nil;
     [super tearDown];
 }