Merge branch 'charlesmchen/fileCleanup'

This commit is contained in:
Michael Kirk 2018-07-26 17:20:25 -06:00
commit 31c6f44b48
8 changed files with 194 additions and 115 deletions

View File

@ -107,8 +107,12 @@ NS_ASSUME_NONNULL_BEGIN
NSData *_Nullable avatarData = [Contact avatarDataForCNContact:cnContact];
if (avatarData) {
NSUInteger hashValue = 0;
NSData *hashData = [Cryptography computeSHA256Digest:avatarData truncatedToBytes:sizeof(hashValue)];
[hashData getBytes:&hashValue length:sizeof(hashValue)];
NSData *_Nullable hashData = [Cryptography computeSHA256Digest:avatarData truncatedToBytes:sizeof(hashValue)];
if (hashData) {
[hashData getBytes:&hashValue length:sizeof(hashValue)];
} else {
OWSProdLogAndFail(@"%@ could not compute hash for avatar.", self.logTag);
}
_imageHash = hashValue;
} else {
_imageHash = 0;

View File

@ -42,7 +42,10 @@ class LegacyContactDiscoveryBatchOperation: OWSOperation {
var phoneNumbersByHashes: [String: String] = [:]
for recipientId in recipientIdsToLookup {
let hash = Cryptography.truncatedSHA1Base64EncodedWithoutPadding(recipientId)
guard let hash = Cryptography.truncatedSHA1Base64EncodedWithoutPadding(recipientId) else {
owsFail("\(logTag) could not hash recipient id: \(recipientId)")
continue
}
assert(phoneNumbersByHashes[hash] == nil)
phoneNumbersByHashes[hash] = recipientId
}

View File

@ -455,12 +455,16 @@ NS_ASSUME_NONNULL_BEGIN
{
NSData *contactData = [colorSeed dataUsingEncoding:NSUTF8StringEncoding];
NSUInteger hashingLength = sizeof(unsigned long long);
unsigned long long choose;
NSData *hashData = [Cryptography computeSHA256Digest:contactData truncatedToBytes:hashingLength];
[hashData getBytes:&choose length:hashingLength];
NSUInteger index = (choose % [self.conversationColorNames count]);
unsigned long long hash = 0;
NSUInteger hashingLength = sizeof(hash);
NSData *_Nullable hashData = [Cryptography computeSHA256Digest:contactData truncatedToBytes:hashingLength];
if (hashData) {
[hashData getBytes:&hash length:hashingLength];
} else {
OWSProdLogAndFail(@"%@ could not compute hash for color seed.", self.logTag);
}
NSUInteger index = (hash % [self.conversationColorNames count]);
return [self.conversationColorNames objectAtIndex:index];
}

View File

@ -220,11 +220,11 @@ static const CGFloat kAttachmentDownloadProgressTheta = 0.001f;
failure:(void (^)(NSError *error))failureHandler
{
NSError *decryptError;
NSData *plaintext = [Cryptography decryptAttachment:cipherText
withKey:attachment.encryptionKey
digest:attachment.digest
unpaddedSize:attachment.byteCount
error:&decryptError];
NSData *_Nullable plaintext = [Cryptography decryptAttachment:cipherText
withKey:attachment.encryptionKey
digest:attachment.digest
unpaddedSize:attachment.byteCount
error:&decryptError];
if (decryptError) {
DDLogError(@"%@ failed to decrypt with error: %@", self.logTag, decryptError);

View File

@ -120,9 +120,15 @@ static const CGFloat kAttachmentUploadProgressTheta = 0.001f;
NSData *encryptionKey;
NSData *digest;
NSData *encryptedAttachmentData =
NSData *_Nullable encryptedAttachmentData =
[Cryptography encryptAttachmentData:attachmentData outKey:&encryptionKey outDigest:&digest];
if (!encryptedAttachmentData) {
OWSProdLogAndFail(@"%@ could not encrypt attachment data.", self.logTag);
error = OWSErrorMakeFailedToSendOutgoingMessageError();
error.isRetryable = YES;
[self reportError:error];
return;
}
attachmentStream.encryptionKey = encryptionKey;
attachmentStream.digest = digest;

View File

@ -737,8 +737,9 @@ NSString *const kNSNotification_SocketManagerStateDidChange = @"kNSNotification_
dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
@try {
NSData *decryptedPayload = [Cryptography decryptAppleMessagePayload:message.body
withSignalingKey:TSAccountManager.signalingKey];
NSData *_Nullable decryptedPayload =
[Cryptography decryptAppleMessagePayload:message.body
withSignalingKey:TSAccountManager.signalingKey];
if (!decryptedPayload) {
DDLogWarn(@"%@ Failed to decrypt incoming payload or bad HMAC", self.logTag);

View File

@ -26,6 +26,8 @@ extern const NSUInteger kAES256_KeyByteLength;
@end
#pragma mark -
@interface AES25GCMEncryptionResult : NSObject
@property (nonatomic, readonly) NSData *ciphertext;
@ -39,6 +41,8 @@ extern const NSUInteger kAES256_KeyByteLength;
@end
#pragma mark -
@interface Cryptography : NSObject
typedef NS_ENUM(NSInteger, TSMACType) {
@ -52,35 +56,30 @@ typedef NS_ENUM(NSInteger, TSMACType) {
+ (uint32_t)randomUInt32;
+ (uint64_t)randomUInt64;
#pragma mark SHA and HMAC methods
#pragma mark - SHA and HMAC methods
// Full length SHA256 digest for `data`
+ (NSData *)computeSHA256Digest:(NSData *)data;
+ (nullable NSData *)computeSHA256Digest:(NSData *)data;
// Truncated SHA256 digest for `data`
+ (NSData *)computeSHA256Digest:(NSData *)data truncatedToBytes:(NSUInteger)truncatedBytes;
+ (nullable NSData *)computeSHA256Digest:(NSData *)data truncatedToBytes:(NSUInteger)truncatedBytes;
+ (NSString *)truncatedSHA1Base64EncodedWithoutPadding:(NSString *)string;
+ (NSString *)computeSHA1DigestForString:(NSString *)input;
+ (nullable NSString *)truncatedSHA1Base64EncodedWithoutPadding:(NSString *)string;
+ (NSData *)computeSHA256HMAC:(NSData *)dataToHMAC withHMACKey:(NSData *)HMACKey;
+ (NSData *)computeSHA1HMAC:(NSData *)dataToHMAC withHMACKey:(NSData *)HMACKey;
+ (NSData *)truncatedSHA1HMAC:(NSData *)dataToHMAC withHMACKey:(NSData *)HMACKey truncation:(NSUInteger)bytes;
+ (NSData *)decryptAppleMessagePayload:(NSData *)payload withSignalingKey:(NSString *)signalingKeyString;
+ (nullable NSData *)decryptAppleMessagePayload:(NSData *)payload withSignalingKey:(NSString *)signalingKeyString;
#pragma mark encrypt and decrypt attachment data
// Though digest can and will be nil for legacy clients, we now reject attachments lacking a digest.
+ (NSData *)decryptAttachment:(NSData *)dataToDecrypt
withKey:(NSData *)key
digest:(nullable NSData *)digest
unpaddedSize:(UInt32)unpaddedSize
error:(NSError **)error;
+ (nullable NSData *)decryptAttachment:(NSData *)dataToDecrypt
withKey:(NSData *)key
digest:(nullable NSData *)digest
unpaddedSize:(UInt32)unpaddedSize
error:(NSError **)error;
+ (NSData *)encryptAttachmentData:(NSData *)attachmentData
outKey:(NSData *_Nonnull *_Nullable)outKey
outDigest:(NSData *_Nonnull *_Nullable)outDigest;
+ (nullable NSData *)encryptAttachmentData:(NSData *)attachmentData
outKey:(NSData *_Nonnull *_Nullable)outKey
outDigest:(NSData *_Nonnull *_Nullable)outDigest;
+ (nullable AES25GCMEncryptionResult *)encryptAESGCMWithData:(NSData *)plaintext
additionalAuthenticatedData:(nullable NSData *)additionalAuthenticatedData

View File

@ -18,7 +18,6 @@
NS_ASSUME_NONNULL_BEGIN
// Returned by many OpenSSL functions - indicating success
const int kOpenSSLSuccess = 1;
@ -96,6 +95,8 @@ const NSUInteger kAES256_KeyByteLength = 32;
@end
#pragma mark -
@implementation AES25GCMEncryptionResult
- (nullable instancetype)initWithCipherText:(NSData *)cipherText
@ -121,9 +122,11 @@ const NSUInteger kAES256_KeyByteLength = 32;
@end
#pragma mark -
@implementation Cryptography
#pragma mark random bytes methods
#pragma mark - random bytes methods
+ (NSData *)generateRandomBytes:(NSUInteger)numberBytes
{
@ -148,93 +151,119 @@ const NSUInteger kAES256_KeyByteLength = 32;
return result;
}
#pragma mark SHA1
#pragma mark - SHA1
// Used by TSContactManager to send hashed/truncated contact list to server.
+ (nullable NSString *)truncatedSHA1Base64EncodedWithoutPadding:(NSString *)string
{
NSData *_Nullable stringData = [string dataUsingEncoding:NSUTF8StringEncoding];
if (!stringData) {
OWSFail(@"%@ could not convert string to utf-8.", self.logTag);
return nil;
}
if (stringData.length >= UINT32_MAX) {
OWSFail(@"%@ string data is too long.", self.logTag);
return nil;
}
uint32_t dataLength = (uint32_t)stringData.length;
+ (NSString *)truncatedSHA1Base64EncodedWithoutPadding:(NSString *)string {
/* used by TSContactManager to send hashed/truncated contact list to server */
NSMutableData *hashData = [NSMutableData dataWithLength:20];
CC_SHA1([string dataUsingEncoding:NSUTF8StringEncoding].bytes,
(unsigned int)[string dataUsingEncoding:NSUTF8StringEncoding].length,
hashData.mutableBytes);
CC_SHA1(stringData.bytes, dataLength, hashData.mutableBytes);
NSData *truncatedData = [hashData subdataWithRange:NSMakeRange(0, 10)];
return [[truncatedData base64EncodedString] stringByReplacingOccurrencesOfString:@"=" withString:@""];
}
+ (NSString *)computeSHA1DigestForString:(NSString *)input {
// Here we are taking in our string hash, placing that inside of a C Char Array, then parsing it through the SHA1
// encryption method.
const char *cstr = [input cStringUsingEncoding:NSUTF8StringEncoding];
NSData *data = [NSData dataWithBytes:cstr length:input.length];
uint8_t digest[CC_SHA1_DIGEST_LENGTH];
#pragma mark - SHA256 Digest
CC_SHA1(data.bytes, (unsigned int)data.length, digest);
+ (nullable NSData *)computeSHA256Digest:(NSData *)data
{
return [self computeSHA256Digest:data truncatedToBytes:CC_SHA256_DIGEST_LENGTH];
}
NSMutableString *output = [NSMutableString stringWithCapacity:CC_SHA1_DIGEST_LENGTH * 2];
for (int i = 0; i < CC_SHA1_DIGEST_LENGTH; i++) {
[output appendFormat:@"%02x", digest[i]];
+ (nullable NSData *)computeSHA256Digest:(NSData *)data truncatedToBytes:(NSUInteger)truncatedBytes
{
if (data.length >= UINT32_MAX) {
OWSFail(@"%@ data is too long.", self.logTag);
return nil;
}
uint32_t dataLength = (uint32_t)data.length;
return output;
}
#pragma mark SHA256 Digest
+ (NSData *)computeSHA256Digest:(NSData *)data
{
return [self computeSHA256Digest:(NSData *)data truncatedToBytes:CC_SHA256_DIGEST_LENGTH];
}
+ (NSData *)computeSHA256Digest:(NSData *)data truncatedToBytes:(NSUInteger)truncatedBytes
{
uint8_t digest[CC_SHA256_DIGEST_LENGTH];
CC_SHA256(data.bytes, (unsigned int)data.length, digest);
CC_SHA256(data.bytes, dataLength, digest);
return
[[NSData dataWithBytes:digest length:CC_SHA256_DIGEST_LENGTH] subdataWithRange:NSMakeRange(0, truncatedBytes)];
}
#pragma mark - HMAC/SHA256
+ (nullable NSData *)computeSHA256HMAC:(NSData *)data withHMACKey:(NSData *)HMACKey
{
if (data.length >= SIZE_MAX) {
OWSFail(@"%@ data is too long.", self.logTag);
return nil;
}
size_t dataLength = (size_t)data.length;
if (HMACKey.length >= SIZE_MAX) {
OWSFail(@"%@ HMAC key is too long.", self.logTag);
return nil;
}
size_t hmacKeyLength = (size_t)HMACKey.length;
#pragma mark HMAC/SHA256
+ (NSData *)computeSHA256HMAC:(NSData *)dataToHMAC withHMACKey:(NSData *)HMACKey {
uint8_t ourHmac[CC_SHA256_DIGEST_LENGTH] = {0};
CCHmac(kCCHmacAlgSHA256, [HMACKey bytes], [HMACKey length], [dataToHMAC bytes], [dataToHMAC length], ourHmac);
CCHmac(kCCHmacAlgSHA256, [HMACKey bytes], hmacKeyLength, [data bytes], dataLength, ourHmac);
return [NSData dataWithBytes:ourHmac length:CC_SHA256_DIGEST_LENGTH];
}
+ (NSData *)computeSHA1HMAC:(NSData *)dataToHMAC withHMACKey:(NSData *)HMACKey {
+ (nullable NSData *)computeSHA1HMAC:(NSData *)data withHMACKey:(NSData *)HMACKey
{
if (data.length >= SIZE_MAX) {
OWSFail(@"%@ data is too long.", self.logTag);
return nil;
}
size_t dataLength = (size_t)data.length;
if (HMACKey.length >= SIZE_MAX) {
OWSFail(@"%@ HMAC key is too long.", self.logTag);
return nil;
}
size_t hmacKeyLength = (size_t)HMACKey.length;
uint8_t ourHmac[CC_SHA256_DIGEST_LENGTH] = {0};
CCHmac(kCCHmacAlgSHA1, [HMACKey bytes], [HMACKey length], [dataToHMAC bytes], [dataToHMAC length], ourHmac);
CCHmac(kCCHmacAlgSHA1, [HMACKey bytes], hmacKeyLength, [data bytes], dataLength, ourHmac);
return [NSData dataWithBytes:ourHmac length:CC_SHA256_DIGEST_LENGTH];
}
+ (NSData *)truncatedSHA1HMAC:(NSData *)dataToHMAC withHMACKey:(NSData *)HMACKey truncation:(NSUInteger)bytes {
+ (nullable NSData *)truncatedSHA1HMAC:(NSData *)dataToHMAC withHMACKey:(NSData *)HMACKey truncation:(NSUInteger)bytes
{
return [[Cryptography computeSHA1HMAC:dataToHMAC withHMACKey:HMACKey] subdataWithRange:NSMakeRange(0, bytes)];
}
+ (NSData *)truncatedSHA256HMAC:(NSData *)dataToHMAC withHMACKey:(NSData *)HMACKey truncation:(NSUInteger)bytes {
+ (nullable NSData *)truncatedSHA256HMAC:(NSData *)dataToHMAC withHMACKey:(NSData *)HMACKey truncation:(NSUInteger)bytes
{
return [[Cryptography computeSHA256HMAC:dataToHMAC withHMACKey:HMACKey] subdataWithRange:NSMakeRange(0, bytes)];
}
#pragma mark AES CBC Mode
#pragma mark - AES CBC Mode
/**
* AES256 CBC encrypt then mac. Used to decrypt both signal messages and attachment blobs
*
* @return decrypted data or nil if hmac invalid/decryption fails
*/
+ (NSData *)decryptCBCMode:(NSData *)dataToDecrypt
key:(NSData *)key
IV:(NSData *)iv
version:(nullable NSData *)version
HMACKey:(NSData *)hmacKey
HMACType:(TSMACType)hmacType
matchingHMAC:(NSData *)hmac
digest:(nullable NSData *)digest
+ (nullable NSData *)decryptCBCMode:(NSData *)dataToDecrypt
key:(NSData *)key
IV:(NSData *)iv
version:(nullable NSData *)version
HMACKey:(NSData *)hmacKey
HMACType:(TSMACType)hmacType
matchingHMAC:(NSData *)hmac
digest:(nullable NSData *)digest
{
if (dataToDecrypt.length >= (SIZE_MAX - kCCBlockSizeAES128)) {
OWSFail(@"%@ data is too long.", self.logTag);
return nil;
}
// Verify hmac of: version? || iv || encrypted data
NSMutableData *dataToAuth = [NSMutableData data];
if (version != nil) {
@ -244,7 +273,7 @@ const NSUInteger kAES256_KeyByteLength = 32;
[dataToAuth appendData:iv];
[dataToAuth appendData:dataToDecrypt];
NSData *ourHmacData;
NSData *_Nullable ourHmacData;
if (hmacType == TSHMACSHA1Truncated10Bytes) {
ourHmacData = [Cryptography truncatedSHA1HMAC:dataToAuth withHMACKey:hmacKey truncation:10];
@ -270,7 +299,7 @@ const NSUInteger kAES256_KeyByteLength = 32;
if (digest) {
DDLogDebug(@"%@ verifying their digest", self.logTag);
[dataToAuth appendData:ourHmacData];
NSData *ourDigest = [Cryptography computeSHA256Digest:dataToAuth];
NSData *_Nullable ourDigest = [Cryptography computeSHA256Digest:dataToAuth];
if (!ourDigest || ![ourDigest ows_constantTimeIsEqualToData:digest]) {
DDLogWarn(@"%@ Bad digest on decrypting payload", self.logTag);
// Don't log digest in prod
@ -313,8 +342,10 @@ const NSUInteger kAES256_KeyByteLength = 32;
return nil;
}
#pragma mark methods which use AES CBC
+ (NSData *)decryptAppleMessagePayload:(NSData *)payload withSignalingKey:(NSString *)signalingKeyString {
#pragma mark - methods which use AES CBC
+ (nullable NSData *)decryptAppleMessagePayload:(NSData *)payload withSignalingKey:(NSString *)signalingKeyString
{
OWSAssert(payload);
OWSAssert(signalingKeyString);
@ -342,11 +373,11 @@ const NSUInteger kAES256_KeyByteLength = 32;
digest:nil];
}
+ (NSData *)decryptAttachment:(NSData *)dataToDecrypt
withKey:(NSData *)key
digest:(nullable NSData *)digest
unpaddedSize:(UInt32)unpaddedSize
error:(NSError **)error
+ (nullable NSData *)decryptAttachment:(NSData *)dataToDecrypt
withKey:(NSData *)key
digest:(nullable NSData *)digest
unpaddedSize:(UInt32)unpaddedSize
error:(NSError **)error
{
if (digest.length <= 0) {
// This *could* happen with sufficiently outdated clients.
@ -377,15 +408,20 @@ const NSUInteger kAES256_KeyByteLength = 32;
NSData *hmac = [dataToDecrypt
subdataWithRange:NSMakeRange([dataToDecrypt length] - HMAC256_OUTPUT_LENGTH, HMAC256_OUTPUT_LENGTH)];
NSData *paddedPlainText = [Cryptography decryptCBCMode:encryptedAttachment
key:encryptionKey
IV:iv
version:nil
HMACKey:hmacKey
HMACType:TSHMACSHA256AttachementType
matchingHMAC:hmac
digest:digest];
if (unpaddedSize == 0) {
NSData *_Nullable paddedPlainText = [Cryptography decryptCBCMode:encryptedAttachment
key:encryptionKey
IV:iv
version:nil
HMACKey:hmacKey
HMACType:TSHMACSHA256AttachementType
matchingHMAC:hmac
digest:digest];
if (!paddedPlainText) {
OWSFail(@"%@ couldn't decrypt attachment.", self.logTag);
*error = OWSErrorWithCodeDescription(
OWSErrorCodeFailedToDecryptMessage, NSLocalizedString(@"ERROR_MESSAGE_INVALID_MESSAGE", @""));
return nil;
} else if (unpaddedSize == 0) {
// Work around for legacy iOS client's which weren't setting padding size.
// Since we know those clients pre-date attachment padding we return the entire data.
DDLogWarn(@"%@ Decrypted attachment with unspecified size.", self.logTag);
@ -424,10 +460,16 @@ const NSUInteger kAES256_KeyByteLength = 32;
}
}
+ (NSData *)encryptAttachmentData:(NSData *)attachmentData
outKey:(NSData *_Nonnull *_Nullable)outKey
outDigest:(NSData *_Nonnull *_Nullable)outDigest
+ (nullable NSData *)encryptAttachmentData:(NSData *)attachmentData
outKey:(NSData *_Nonnull *_Nullable)outKey
outDigest:(NSData *_Nonnull *_Nullable)outDigest
{
// Due to paddedSize, we need to divide by two.
if (attachmentData.length >= SIZE_MAX / 2) {
DDLogError(@"%@ data is too long.", self.logTag);
return nil;
}
NSData *iv = [Cryptography generateRandomBytes:AES_CBC_IV_LENGTH];
NSData *encryptionKey = [Cryptography generateRandomBytes:AES_KEY_SIZE];
NSData *hmacKey = [Cryptography generateRandomBytes:HMAC256_KEY_LENGTH];
@ -478,13 +520,22 @@ const NSUInteger kAES256_KeyByteLength = 32;
[encryptedPaddedData appendData:cipherText];
// compute hmac of: iv || encrypted data
NSData *hmac =
NSData *_Nullable hmac =
[Cryptography truncatedSHA256HMAC:encryptedPaddedData withHMACKey:hmacKey truncation:HMAC256_OUTPUT_LENGTH];
if (!hmac) {
OWSFail(@"%@ could not compute SHA 256 HMAC.", self.logTag);
return nil;
}
[encryptedPaddedData appendData:hmac];
// compute digest of: iv || encrypted data || hmac
*outDigest = [self computeSHA256Digest:encryptedPaddedData];
NSData *_Nullable digest = [self computeSHA256Digest:encryptedPaddedData];
if (!digest) {
OWSFail(@"%@ data is too long.", self.logTag);
return nil;
}
*outDigest = digest;
return [encryptedPaddedData copy];
}
@ -526,7 +577,7 @@ const NSUInteger kAES256_KeyByteLength = 32;
// Provide any AAD data. This can be called zero or more times as
// required
if (additionalAuthenticatedData != nil) {
if (additionalAuthenticatedData.length >= INT32_MAX) {
if (additionalAuthenticatedData.length >= INT_MAX) {
OWSFail(@"%@ additionalAuthenticatedData too large", self.logTag);
return nil;
}
@ -538,7 +589,7 @@ const NSUInteger kAES256_KeyByteLength = 32;
}
}
if (plaintext.length >= UINT32_MAX) {
if (plaintext.length >= INT_MAX) {
OWSFail(@"%@ plaintext too large", self.logTag);
return nil;
}
@ -631,12 +682,15 @@ const NSUInteger kAES256_KeyByteLength = 32;
// Provide any AAD data. This can be called zero or more times as
// required
if (additionalAuthenticatedData) {
if (additionalAuthenticatedData.length >= INT32_MAX) {
if (additionalAuthenticatedData.length >= INT_MAX) {
OWSFail(@"%@ additionalAuthenticatedData too large", self.logTag);
return nil;
}
if (!EVP_DecryptUpdate(
ctx, NULL, &decryptedBytes, additionalAuthenticatedData.bytes, additionalAuthenticatedData.length)) {
if (!EVP_DecryptUpdate(ctx,
NULL,
&decryptedBytes,
additionalAuthenticatedData.bytes,
(int)additionalAuthenticatedData.length)) {
OWSFail(@"%@ failed during additionalAuthenticatedData", self.logTag);
return nil;
}
@ -647,6 +701,10 @@ const NSUInteger kAES256_KeyByteLength = 32;
// If we wanted to save memory, we could decrypt piece-wise from an iostream -
// feeding each chunk to EVP_DecryptUpdate, which can be called multiple times.
// For simplicity, we currently decrypt the entire ciphertext in one shot.
if (ciphertext.length >= INT_MAX) {
OWSFail(@"%@ ciphertext too large", self.logTag);
return nil;
}
if (EVP_DecryptUpdate(ctx, plaintext.mutableBytes, &decryptedBytes, ciphertext.bytes, (int)ciphertext.length)
!= kOpenSSLSuccess) {
OWSFail(@"%@ decryptUpdate failed", self.logTag);
@ -659,6 +717,10 @@ const NSUInteger kAES256_KeyByteLength = 32;
}
// Set expected tag value. Works in OpenSSL 1.0.1d and later
if (authTagFromEncrypt.length >= INT_MAX) {
OWSFail(@"%@ authTagFromEncrypt too large", self.logTag);
return nil;
}
if (EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_GCM_SET_TAG, (int)authTagFromEncrypt.length, (void *)authTagFromEncrypt.bytes)
!= kOpenSSLSuccess) {
OWSFail(@"%@ Failed to set auth tag in decrypt.", self.logTag);