Merge remote-tracking branch 'OLMKit/olmkit' into olmkit

# Conflicts:
#	.gitignore
#	include/olm/olm.hh
#	javascript/README.md

13 files changed, 756 insertions, 0 deletions

diff --git a/xcode/OLMKit/Info.plist b/xcode/OLMKit/Info.plist
new file mode 100644
index 0000000..d3de8ee
--- /dev/null
+++ b/xcode/OLMKit/Info.plist
@@ -0,0 +1,26 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
+<plist version="1.0">
+<dict>
+	<key>CFBundleDevelopmentRegion</key>
+	<string>en</string>
+	<key>CFBundleExecutable</key>
+	<string>$(EXECUTABLE_NAME)</string>
+	<key>CFBundleIdentifier</key>
+	<string>$(PRODUCT_BUNDLE_IDENTIFIER)</string>
+	<key>CFBundleInfoDictionaryVersion</key>
+	<string>6.0</string>
+	<key>CFBundleName</key>
+	<string>$(PRODUCT_NAME)</string>
+	<key>CFBundlePackageType</key>
+	<string>FMWK</string>
+	<key>CFBundleShortVersionString</key>
+	<string>1.0</string>
+	<key>CFBundleSignature</key>
+	<string>????</string>
+	<key>CFBundleVersion</key>
+	<string>$(CURRENT_PROJECT_VERSION)</string>
+	<key>NSPrincipalClass</key>
+	<string></string>
+</dict>
+</plist>
diff --git a/xcode/OLMKit/OLMAccount.h b/xcode/OLMKit/OLMAccount.h
new file mode 100644
index 0000000..a2923f9
--- /dev/null
+++ b/xcode/OLMKit/OLMAccount.h
@@ -0,0 +1,41 @@
+//
+//  OLMAccount.h
+//  olm
+//
+//  Created by Chris Ballinger on 4/8/16.
+//
+//
+
+#import <Foundation/Foundation.h>
+#import "OLMSerializable.h"
+
+@class OLMSession;
+
+@interface OLMAccount : NSObject <OLMSerializable, NSSecureCoding>
+
+/** Creates new account */
+- (instancetype) initNewAccount;
+
+/** public identity keys. base64 encoded in "curve25519" and "ed25519" keys */
+- (NSDictionary*) identityKeys;
+
+/** signs message with ed25519 key for account */
+- (NSString*) signMessage:(NSData*)messageData;
+
+/** Public parts of the unpublished one time keys for the account */
+- (NSDictionary*) oneTimeKeys;
+
+- (BOOL) removeOneTimeKeysForSession:(OLMSession*)session;
+
+/** Marks the current set of one time keys as being published. */
+- (void) markKeysAsPublished;
+
+/** The largest number of one time keys this account can store. */
+- (NSUInteger) maxOneTimeKeys;
+
+/** Generates a number of new one time keys. If the total number of keys stored
+ * by this account exceeds -maxOneTimeKeys then the old keys are
+ * discarded. */
+- (void) generateOneTimeKeys:(NSUInteger)numberOfKeys;
+
+@end
diff --git a/xcode/OLMKit/OLMAccount.m b/xcode/OLMKit/OLMAccount.m
new file mode 100644
index 0000000..4561a37
--- /dev/null
+++ b/xcode/OLMKit/OLMAccount.m
@@ -0,0 +1,229 @@
+//
+//  OLMAccount.m
+//  olm
+//
+//  Created by Chris Ballinger on 4/8/16.
+//
+//
+
+#import "OLMAccount.h"
+#import "OLMAccount_Private.h"
+#import "OLMSession.h"
+#import "OLMSession_Private.h"
+#import "OLMUtility.h"
+
+@import Security;
+
+@implementation OLMAccount
+
+- (void) dealloc {
+    olm_clear_account(_account);
+    free(_account);
+}
+
+- (BOOL) initializeAccountMemory {
+    size_t accountSize = olm_account_size();
+    _account = malloc(accountSize);
+    NSParameterAssert(_account != nil);
+    if (!_account) {
+        return NO;
+    }
+    _account = olm_account(_account);
+    NSParameterAssert(_account != nil);
+    if (!_account) {
+        return NO;
+    }
+    return YES;
+}
+
+- (instancetype) init {
+    self = [super init];
+    if (!self) {
+        return nil;
+    }
+    BOOL success = [self initializeAccountMemory];
+    if (!success) {
+        return nil;
+    }
+    return self;
+}
+
+- (instancetype) initNewAccount {
+    self = [self init];
+    if (!self) {
+        return nil;
+    }
+    size_t randomLength = olm_create_account_random_length(_account);
+    NSMutableData *random = [OLMUtility randomBytesOfLength:randomLength];
+    size_t accountResult = olm_create_account(_account, random.mutableBytes, random.length);
+    if (accountResult == olm_error()) {
+        const char *error = olm_account_last_error(_account);
+        NSLog(@"error creating account: %s", error);
+        return nil;
+    }
+    return self;
+}
+
+- (size_t) maxOneTimeKeys {
+    return olm_account_max_number_of_one_time_keys(_account);
+}
+
+
+/** public identity keys */
+- (NSDictionary*) identityKeys {
+    size_t identityKeysLength = olm_account_identity_keys_length(_account);
+    uint8_t *identityKeysBytes = malloc(identityKeysLength);
+    if (!identityKeysBytes) {
+        return nil;
+    }
+    size_t result = olm_account_identity_keys(_account, identityKeysBytes, identityKeysLength);
+    if (result == olm_error()) {
+        const char *error = olm_account_last_error(_account);
+        NSLog(@"error getting id keys: %s", error);
+        free(identityKeysBytes);
+        return nil;
+    }
+    NSData *idKeyData = [NSData dataWithBytesNoCopy:identityKeysBytes length:identityKeysLength freeWhenDone:YES];
+    NSError *error = nil;
+    NSDictionary *keysDictionary = [NSJSONSerialization JSONObjectWithData:idKeyData options:0 error:&error];
+    if (error) {
+        NSLog(@"Could not decode JSON: %@", error.localizedDescription);
+    }
+    return keysDictionary;
+}
+
+- (NSDictionary*) oneTimeKeys {
+    size_t otkLength = olm_account_one_time_keys_length(_account);
+    uint8_t *otkBytes = malloc(otkLength);
+    if (!otkBytes) {
+        return nil;
+    }
+    size_t result = olm_account_one_time_keys(_account, otkBytes, otkLength);
+    if (result == olm_error()) {
+        const char *error = olm_account_last_error(_account);
+        NSLog(@"error getting id keys: %s", error);
+        free(otkBytes);
+    }
+    NSData *otk = [NSData dataWithBytesNoCopy:otkBytes length:otkLength freeWhenDone:YES];
+    NSError *error = nil;
+    NSDictionary *keysDictionary = [NSJSONSerialization JSONObjectWithData:otk options:0 error:&error];
+    if (error) {
+        NSLog(@"Could not decode JSON: %@", error.localizedDescription);
+    }
+    return keysDictionary;
+}
+
+
+- (void) generateOneTimeKeys:(NSUInteger)numberOfKeys {
+    size_t randomLength = olm_account_generate_one_time_keys_random_length(_account, numberOfKeys);
+    NSMutableData *random = [OLMUtility randomBytesOfLength:randomLength];
+    size_t result = olm_account_generate_one_time_keys(_account, numberOfKeys, random.mutableBytes, random.length);
+    if (result == olm_error()) {
+        const char *error = olm_account_last_error(_account);
+        NSLog(@"error generating keys: %s", error);
+    }
+}
+
+- (BOOL) removeOneTimeKeysForSession:(OLMSession *)session {
+    NSParameterAssert(session != nil);
+    if (!session) {
+        return nil;
+    }
+    size_t result = olm_remove_one_time_keys(self.account, session.session);
+    if (result == olm_error()) {
+        const char *error = olm_session_last_error(session.session);
+        NSAssert(NO, @"olm_remove_one_time_keys error: %s", error);
+        return NO;
+    }
+    return YES;
+}
+
+#pragma mark OLMSerializable
+
+/** Initializes from encrypted serialized data. Will throw error if invalid key or invalid base64. */
+- (instancetype) initWithSerializedData:(NSString*)serializedData key:(NSData*)key error:(NSError**)error {
+    self = [self init];
+    if (!self) {
+        return nil;
+    }
+    NSParameterAssert(key.length > 0);
+    NSParameterAssert(serializedData.length > 0);
+    if (key.length == 0 || serializedData.length == 0) {
+        if (error) {
+            *error = [NSError errorWithDomain:@"org.matrix.olm" code:0 userInfo:@{NSLocalizedDescriptionKey: @"Bad length."}];
+        }
+        return nil;
+    }
+    NSMutableData *pickle = [serializedData dataUsingEncoding:NSUTF8StringEncoding].mutableCopy;
+    size_t result = olm_unpickle_account(_account, key.bytes, key.length, pickle.mutableBytes, pickle.length);
+    if (result == olm_error()) {
+        const char *olm_error = olm_account_last_error(_account);
+        NSString *errorString = [NSString stringWithUTF8String:olm_error];
+        if (error && errorString) {
+            *error = [NSError errorWithDomain:@"org.matrix.olm" code:0 userInfo:@{NSLocalizedDescriptionKey: errorString}];
+        }
+        return nil;
+    }
+    return self;
+}
+
+/** Serializes and encrypts object data, outputs base64 blob */
+- (NSString*) serializeDataWithKey:(NSData*)key error:(NSError**)error {
+    NSParameterAssert(key.length > 0);
+    size_t length = olm_pickle_account_length(_account);
+    NSMutableData *pickled = [NSMutableData dataWithLength:length];
+    size_t result = olm_pickle_account(_account, key.bytes, key.length, pickled.mutableBytes, pickled.length);
+    if (result == olm_error()) {
+        const char *olm_error = olm_account_last_error(_account);
+        NSString *errorString = [NSString stringWithUTF8String:olm_error];
+        if (error && errorString) {
+            *error = [NSError errorWithDomain:@"org.matrix.olm" code:0 userInfo:@{NSLocalizedDescriptionKey: errorString}];
+        }
+        return nil;
+    }
+    NSString *pickleString = [[NSString alloc] initWithData:pickled encoding:NSUTF8StringEncoding];
+    return pickleString;
+}
+
+#pragma mark NSSecureCoding
+
++ (BOOL) supportsSecureCoding {
+    return YES;
+}
+
+#pragma mark NSCoding
+
+- (id)initWithCoder:(NSCoder *)decoder {
+    NSString *version = [decoder decodeObjectOfClass:[NSString class] forKey:@"version"];
+    
+    NSError *error = nil;
+    
+    if ([version isEqualToString:@"1"]) {
+        NSString *pickle = [decoder decodeObjectOfClass:[NSString class] forKey:@"pickle"];
+        NSData *key = [decoder decodeObjectOfClass:[NSData class] forKey:@"key"];
+
+        self = [self initWithSerializedData:pickle key:key error:&error];
+    }
+    
+    NSParameterAssert(error == nil);
+    NSParameterAssert(self != nil);
+    if (!self) {
+        return nil;
+    }
+    
+    return self;
+}
+
+- (void)encodeWithCoder:(NSCoder *)encoder {
+    NSData *key = [OLMUtility randomBytesOfLength:32];
+    NSError *error = nil;
+    NSString *pickle = [self serializeDataWithKey:key error:&error];
+    NSParameterAssert(pickle.length > 0 && error == nil);
+    
+    [encoder encodeObject:pickle forKey:@"pickle"];
+    [encoder encodeObject:key forKey:@"key"];
+    [encoder encodeObject:@"1" forKey:@"version"];
+}
+
+
+@end
diff --git a/xcode/OLMKit/OLMAccount_Private.h b/xcode/OLMKit/OLMAccount_Private.h
new file mode 100644
index 0000000..4eb3e2b
--- /dev/null
+++ b/xcode/OLMKit/OLMAccount_Private.h
@@ -0,0 +1,15 @@
+//
+//  OLMAccount_Private.h
+//  olm
+//
+//  Created by Chris Ballinger on 4/8/16.
+//
+//
+
+@import olm;
+
+@interface OLMAccount()
+
+@property (nonatomic) OlmAccount *account;
+
+@end
\ No newline at end of file
diff --git a/xcode/OLMKit/OLMKit.h b/xcode/OLMKit/OLMKit.h
new file mode 100644
index 0000000..745af43
--- /dev/null
+++ b/xcode/OLMKit/OLMKit.h
@@ -0,0 +1,23 @@
+//
+//  OLMKit.h
+//  OLMKit
+//
+//  Created by Chris Ballinger on 4/8/16.
+//
+//
+
+#import <UIKit/UIKit.h>
+
+//! Project version number for OLMKit.
+FOUNDATION_EXPORT double OLMKitVersionNumber;
+
+//! Project version string for OLMKit.
+FOUNDATION_EXPORT const unsigned char OLMKitVersionString[];
+
+// In this header, you should import all the public headers of your framework using statements like #import <OLMKit/PublicHeader.h>
+
+
+#import "OLMAccount.h"
+#import "OLMSession.h"
+#import "OLMMessage.h"
+#import "OLMUtility.h"
\ No newline at end of file
diff --git a/xcode/OLMKit/OLMMessage.h b/xcode/OLMKit/OLMMessage.h
new file mode 100644
index 0000000..97c748f
--- /dev/null
+++ b/xcode/OLMKit/OLMMessage.h
@@ -0,0 +1,28 @@
+//
+//  OLMMessage.h
+//  olm
+//
+//  Created by Chris Ballinger on 4/8/16.
+//
+//
+
+#import <Foundation/Foundation.h>
+
+/*
+ from olm.hh
+ static const size_t OLM_MESSAGE_TYPE_PRE_KEY = 0;
+ static const size_t OLM_MESSAGE_TYPE_MESSAGE = 1;
+ */
+typedef NS_ENUM(NSInteger, OLMMessageType) {
+    OLMMessageTypePreKey = 0,
+    OLMMessageTypeMessage = 1
+};
+
+@interface OLMMessage : NSObject
+
+@property (nonatomic, copy, readonly, nonnull) NSString *ciphertext;
+@property (readonly) OLMMessageType type;
+
+- (nullable instancetype) initWithCiphertext:(nonnull NSString*)ciphertext type:(OLMMessageType)type;
+
+@end
diff --git a/xcode/OLMKit/OLMMessage.m b/xcode/OLMKit/OLMMessage.m
new file mode 100644
index 0000000..d0cfb41
--- /dev/null
+++ b/xcode/OLMKit/OLMMessage.m
@@ -0,0 +1,24 @@
+//
+//  OLMMessage.m
+//  olm
+//
+//  Created by Chris Ballinger on 4/8/16.
+//
+//
+
+#import "OLMMessage.h"
+
+@implementation OLMMessage
+
+- (nullable instancetype) initWithCiphertext:(nonnull NSString*)ciphertext type:(OLMMessageType)type {
+    NSParameterAssert(ciphertext != nil);
+    self = [super init];
+    if (!self) {
+        return nil;
+    }
+    _ciphertext = [ciphertext copy];
+    _type = type;
+    return self;
+}
+
+@end
diff --git a/xcode/OLMKit/OLMSerializable.h b/xcode/OLMKit/OLMSerializable.h
new file mode 100644
index 0000000..b4b115a
--- /dev/null
+++ b/xcode/OLMKit/OLMSerializable.h
@@ -0,0 +1,19 @@
+//
+//  OLMSerializable.h
+//  olm
+//
+//  Created by Chris Ballinger on 4/8/16.
+//
+//
+
+#import <Foundation/Foundation.h>
+
+@protocol OLMSerializable <NSObject>
+
+/** Initializes from encrypted serialized data. Will throw error if invalid key or invalid base64. */
+- (instancetype) initWithSerializedData:(NSString*)serializedData key:(NSData*)key error:(NSError**)error;
+
+/** Serializes and encrypts object data, outputs base64 blob */
+- (NSString*) serializeDataWithKey:(NSData*)key error:(NSError**)error;
+
+@end
diff --git a/xcode/OLMKit/OLMSession.h b/xcode/OLMKit/OLMSession.h
new file mode 100644
index 0000000..c209564
--- /dev/null
+++ b/xcode/OLMKit/OLMSession.h
@@ -0,0 +1,34 @@
+//
+//  OLMSession.h
+//  olm
+//
+//  Created by Chris Ballinger on 4/8/16.
+//
+//
+
+#import <Foundation/Foundation.h>
+#import "OLMSerializable.h"
+#import "OLMAccount.h"
+#import "OLMMessage.h"
+
+@interface OLMSession : NSObject <OLMSerializable, NSSecureCoding>
+
+- (instancetype) initOutboundSessionWithAccount:(OLMAccount*)account theirIdentityKey:(NSString*)theirIdentityKey theirOneTimeKey:(NSString*)theirOneTimeKey;
+
+- (instancetype) initInboundSessionWithAccount:(OLMAccount*)account oneTimeKeyMessage:(NSString*)oneTimeKeyMessage;
+
+- (instancetype) initInboundSessionWithAccount:(OLMAccount*)account theirIdentityKey:(NSString*)theirIdentityKey oneTimeKeyMessage:(NSString*)oneTimeKeyMessage;
+
+- (NSString*) sessionIdentifier;
+
+- (BOOL) matchesInboundSession:(NSString*)oneTimeKeyMessage;
+
+- (BOOL) matchesInboundSessionFrom:(NSString*)theirIdentityKey oneTimeKeyMessage:(NSString *)oneTimeKeyMessage;
+
+/** UTF-8 plaintext -> base64 ciphertext */
+- (OLMMessage*) encryptMessage:(NSString*)message;
+
+/** base64 ciphertext -> UTF-8 plaintext */
+- (NSString*) decryptMessage:(OLMMessage*)message;
+
+@end
diff --git a/xcode/OLMKit/OLMSession.m b/xcode/OLMKit/OLMSession.m
new file mode 100644
index 0000000..119079f
--- /dev/null
+++ b/xcode/OLMKit/OLMSession.m
@@ -0,0 +1,261 @@
+//
+//  OLMSession.m
+//  olm
+//
+//  Created by Chris Ballinger on 4/8/16.
+//
+//
+
+#import "OLMSession.h"
+#import "OLMUtility.h"
+#import "OLMAccount_Private.h"
+#import "OLMSession_Private.h"
+@import olm;
+
+@implementation OLMSession
+
+- (void) dealloc {
+    olm_clear_session(_session);
+    free(_session);
+}
+
+- (BOOL) initializeSessionMemory {
+    size_t size = olm_session_size();
+    _session = malloc(size);
+    NSParameterAssert(_session != nil);
+    if (!_session) {
+        return NO;
+    }
+    _session = olm_session(_session);
+    NSParameterAssert(_session != nil);
+    if (!_session) {
+        return NO;
+    }
+    return YES;
+}
+
+- (instancetype) init {
+    self = [super init];
+    if (!self) {
+        return nil;
+    }
+    BOOL success = [self initializeSessionMemory];
+    if (!success) {
+        return nil;
+    }
+    return self;
+}
+
+- (instancetype) initWithAccount:(OLMAccount*)account {
+    self = [self init];
+    if (!self) {
+        return nil;
+    }
+    NSParameterAssert(account != nil &&  account.account != NULL);
+    if (account == nil || account.account == NULL) {
+        return nil;
+    }
+    _account = account;
+    return self;
+}
+
+- (instancetype) initOutboundSessionWithAccount:(OLMAccount*)account theirIdentityKey:(NSString*)theirIdentityKey theirOneTimeKey:(NSString*)theirOneTimeKey {
+    self = [self initWithAccount:account];
+    if (!self) {
+        return nil;
+    }
+    NSMutableData *random = [OLMUtility randomBytesOfLength:olm_create_outbound_session_random_length(_session)];
+    NSData *idKey = [theirIdentityKey dataUsingEncoding:NSUTF8StringEncoding];
+    NSData *otKey = [theirOneTimeKey dataUsingEncoding:NSUTF8StringEncoding];
+    size_t result = olm_create_outbound_session(_session, account.account, idKey.bytes, idKey.length, otKey.bytes, otKey.length, random.mutableBytes, random.length);
+    if (result == olm_error()) {
+        const char *error = olm_session_last_error(_session);
+        NSAssert(NO, @"olm_create_outbound_session error: %s", error);
+        return nil;
+    }
+    return self;
+}
+
+- (instancetype) initInboundSessionWithAccount:(OLMAccount*)account oneTimeKeyMessage:(NSString*)oneTimeKeyMessage {
+    self = [self initWithAccount:account];
+    if (!self) {
+        return nil;
+    }
+    NSMutableData *otk = [NSMutableData dataWithData:[oneTimeKeyMessage dataUsingEncoding:NSUTF8StringEncoding]];
+    size_t result = olm_create_inbound_session(_session, account.account, otk.mutableBytes, oneTimeKeyMessage.length);
+    if (result == olm_error()) {
+        const char *error = olm_session_last_error(_session);
+        NSAssert(NO, @"olm_create_inbound_session error: %s", error);
+        return nil;
+    }
+    return self;
+}
+
+- (instancetype) initInboundSessionWithAccount:(OLMAccount*)account theirIdentityKey:(NSString*)theirIdentityKey oneTimeKeyMessage:(NSString*)oneTimeKeyMessage {
+    self = [self initWithAccount:account];
+    if (!self) {
+        return nil;
+    }
+    NSData *idKey = [theirIdentityKey dataUsingEncoding:NSUTF8StringEncoding];
+    NSMutableData *otk = [NSMutableData dataWithData:[oneTimeKeyMessage dataUsingEncoding:NSUTF8StringEncoding]];
+    size_t result = olm_create_inbound_session_from(_session, account.account, idKey.bytes, idKey.length, otk.mutableBytes, otk.length);
+    if (result == olm_error()) {
+        const char *error = olm_session_last_error(_session);
+        NSAssert(NO, @"olm_create_inbound_session_from error: %s", error);
+        return nil;
+    }
+    return self;
+}
+
+- (NSString*) sessionIdentifier {
+    size_t length = olm_session_id_length(_session);
+    NSMutableData *idData = [NSMutableData dataWithLength:length];
+    if (!idData) {
+        return nil;
+    }
+    size_t result = olm_session_id(_session, idData.mutableBytes, idData.length);
+    if (result == olm_error()) {
+        const char *error = olm_session_last_error(_session);
+        NSAssert(NO, @"olm_session_id error: %s", error);
+        return nil;
+    }
+    NSString *idString = [[NSString alloc] initWithData:idData encoding:NSUTF8StringEncoding];
+    return idString;
+}
+
+- (OLMMessage*) encryptMessage:(NSString*)message {
+    size_t messageType = olm_encrypt_message_type(_session);
+    size_t randomLength = olm_encrypt_random_length(_session);
+    NSMutableData *random = [OLMUtility randomBytesOfLength:randomLength];
+    NSData *plaintextData = [message dataUsingEncoding:NSUTF8StringEncoding];
+    size_t ciphertextLength = olm_encrypt_message_length(_session, plaintextData.length);
+    NSMutableData *ciphertext = [NSMutableData dataWithLength:ciphertextLength];
+    if (!ciphertext) {
+        return nil;
+    }
+    size_t result = olm_encrypt(_session, plaintextData.bytes, plaintextData.length, random.mutableBytes, random.length, ciphertext.mutableBytes, ciphertext.length);
+    if (result == olm_error()) {
+        const char *error = olm_session_last_error(_session);
+        NSAssert(NO, @"olm_encrypt error: %s", error);
+        return nil;
+    }
+    NSString *ciphertextString = [[NSString alloc] initWithData:ciphertext encoding:NSUTF8StringEncoding];
+    OLMMessage *encryptedMessage = [[OLMMessage alloc] initWithCiphertext:ciphertextString type:messageType];
+    return encryptedMessage;
+}
+
+- (NSString*) decryptMessage:(OLMMessage*)message {
+    NSParameterAssert(message != nil);
+    NSData *messageData = [message.ciphertext dataUsingEncoding:NSUTF8StringEncoding];
+    if (!messageData) {
+        return nil;
+    }
+    NSMutableData *mutMessage = messageData.mutableCopy;
+    size_t maxPlaintextLength = olm_decrypt_max_plaintext_length(_session, message.type, mutMessage.mutableBytes, mutMessage.length);
+    if (maxPlaintextLength == olm_error()) {
+        const char *error = olm_session_last_error(_session);
+        NSAssert(NO, @"olm_decrypt_max_plaintext_length error: %s", error);
+        return nil;
+    }
+    // message buffer is destroyed by olm_decrypt_max_plaintext_length
+    mutMessage = messageData.mutableCopy;
+    NSMutableData *plaintextData = [NSMutableData dataWithLength:maxPlaintextLength];
+    size_t plaintextLength = olm_decrypt(_session, message.type, mutMessage.mutableBytes, mutMessage.length, plaintextData.mutableBytes, plaintextData.length);
+    if (plaintextLength == olm_error()) {
+        const char *error = olm_session_last_error(_session);
+        NSAssert(NO, @"olm_decrypt error: %s", error);
+        return nil;
+    }
+    plaintextData.length = plaintextLength;
+    NSString *plaintext = [[NSString alloc] initWithData:plaintextData encoding:NSUTF8StringEncoding];
+    return plaintext;
+}
+
+#pragma mark OLMSerializable
+
+/** Initializes from encrypted serialized data. Will throw error if invalid key or invalid base64. */
+- (instancetype) initWithSerializedData:(NSString*)serializedData key:(NSData*)key error:(NSError**)error {
+    self = [self init];
+    if (!self) {
+        return nil;
+    }
+    NSParameterAssert(key.length > 0);
+    NSParameterAssert(serializedData.length > 0);
+    if (key.length == 0 || serializedData.length == 0) {
+        if (error) {
+            *error = [NSError errorWithDomain:@"org.matrix.olm" code:0 userInfo:@{NSLocalizedDescriptionKey: @"Bad length."}];
+        }
+        return nil;
+    }
+    NSMutableData *pickle = [serializedData dataUsingEncoding:NSUTF8StringEncoding].mutableCopy;
+    size_t result = olm_unpickle_session(_session, key.bytes, key.length, pickle.mutableBytes, pickle.length);
+    if (result == olm_error()) {
+        const char *olm_error = olm_session_last_error(_session);
+        NSString *errorString = [NSString stringWithUTF8String:olm_error];
+        if (error && errorString) {
+            *error = [NSError errorWithDomain:@"org.matrix.olm" code:0 userInfo:@{NSLocalizedDescriptionKey: errorString}];
+        }
+        return nil;
+    }
+    return self;
+}
+
+/** Serializes and encrypts object data, outputs base64 blob */
+- (NSString*) serializeDataWithKey:(NSData*)key error:(NSError**)error {
+    NSParameterAssert(key.length > 0);
+    size_t length = olm_pickle_session_length(_session);
+    NSMutableData *pickled = [NSMutableData dataWithLength:length];
+    size_t result = olm_pickle_session(_session, key.bytes, key.length, pickled.mutableBytes, pickled.length);
+    if (result == olm_error()) {
+        const char *olm_error = olm_session_last_error(_session);
+        NSString *errorString = [NSString stringWithUTF8String:olm_error];
+        if (error && errorString) {
+            *error = [NSError errorWithDomain:@"org.matrix.olm" code:0 userInfo:@{NSLocalizedDescriptionKey: errorString}];
+        }
+        return nil;
+    }
+    NSString *pickleString = [[NSString alloc] initWithData:pickled encoding:NSUTF8StringEncoding];
+    return pickleString;
+}
+
+#pragma mark NSSecureCoding
+
++ (BOOL) supportsSecureCoding {
+    return YES;
+}
+
+#pragma mark NSCoding
+
+- (id)initWithCoder:(NSCoder *)decoder {
+    NSString *version = [decoder decodeObjectOfClass:[NSString class] forKey:@"version"];
+    
+    NSError *error = nil;
+    
+    if ([version isEqualToString:@"1"]) {
+        NSString *pickle = [decoder decodeObjectOfClass:[NSString class] forKey:@"pickle"];
+        NSData *key = [decoder decodeObjectOfClass:[NSData class] forKey:@"key"];
+        
+        self = [self initWithSerializedData:pickle key:key error:&error];
+    }
+    
+    NSParameterAssert(error == nil);
+    NSParameterAssert(self != nil);
+    if (!self) {
+        return nil;
+    }
+    
+    return self;
+}
+
+- (void)encodeWithCoder:(NSCoder *)encoder {
+    NSData *key = [OLMUtility randomBytesOfLength:32];
+    NSError *error = nil;
+    NSString *pickle = [self serializeDataWithKey:key error:&error];
+    NSParameterAssert(pickle.length > 0 && error == nil);
+    
+    [encoder encodeObject:pickle forKey:@"pickle"];
+    [encoder encodeObject:key forKey:@"key"];
+    [encoder encodeObject:@"1" forKey:@"version"];
+}
+
+@end
diff --git a/xcode/OLMKit/OLMSession_Private.h b/xcode/OLMKit/OLMSession_Private.h
new file mode 100644
index 0000000..d906b14
--- /dev/null
+++ b/xcode/OLMKit/OLMSession_Private.h
@@ -0,0 +1,16 @@
+//
+//  OLMSession_Private.h
+//  olm
+//
+//  Created by Chris Ballinger on 4/13/16.
+//
+//
+
+@import olm;
+
+@interface OLMSession()
+
+@property (nonatomic) OlmSession *session;
+@property (nonatomic, strong) OLMAccount *account;
+
+@end
\ No newline at end of file
diff --git a/xcode/OLMKit/OLMUtility.h b/xcode/OLMKit/OLMUtility.h
new file mode 100644
index 0000000..8acbf40
--- /dev/null
+++ b/xcode/OLMKit/OLMUtility.h
@@ -0,0 +1,15 @@
+//
+//  OLMUtility.h
+//  olm
+//
+//  Created by Chris Ballinger on 4/8/16.
+//
+//
+
+#import <Foundation/Foundation.h>
+
+@interface OLMUtility : NSObject
+
++ (NSMutableData*) randomBytesOfLength:(NSUInteger)length;
+
+@end
diff --git a/xcode/OLMKit/OLMUtility.m b/xcode/OLMKit/OLMUtility.m
new file mode 100644
index 0000000..5dbe644
--- /dev/null
+++ b/xcode/OLMKit/OLMUtility.m
@@ -0,0 +1,25 @@
+//
+//  OLMUtility.m
+//  olm
+//
+//  Created by Chris Ballinger on 4/8/16.
+//
+//
+
+#import "OLMUtility.h"
+
+@implementation OLMUtility
+
++ (NSMutableData*) randomBytesOfLength:(NSUInteger)length {
+    NSMutableData *randomData = [NSMutableData dataWithLength:length];
+    if (!randomData) {
+        return nil;
+    }
+    int result = SecRandomCopyBytes(kSecRandomDefault, randomData.length, randomData.mutableBytes);
+    if (result != 0) {
+        return nil;
+    }
+    return randomData;
+}
+
+@end