session-ios/Signal/test/textsecure/CryptographyTests.mm

//
//  CryptographyTests.m
//  TextSecureiOS
//
//  Created by Christine Corbett Moran on 12/19/13.
//  Copyright (c) 2013 Open Whisper Systems. All rights reserved.
//

#import <XCTest/XCTest.h>
#include <stdlib.h>
#import "Cryptography.h"
#import "NSData+Base64.h"

@interface CryptographyTests : XCTestCase

@end


@interface Cryptography (Test)
+(NSData*) truncatedSHA256HMAC:(NSData*)dataToHMAC withHMACKey:(NSData*)HMACKey truncation:(int)bytes;
+(NSData*)encryptCBCMode:(NSData*) dataToEncrypt withKey:(NSData*) key withIV:(NSData*) iv withVersion:(NSData*)version  withHMACKey:(NSData*) hmacKey withHMACType:(TSMACType)hmacType computedHMAC:(NSData**)hmac;

+(NSData*)decryptCBCMode:(NSData*)dataToDecrypt
                     key:(NSData*)key
                      IV:(NSData*)iv
                 version:(NSData*)version
                 HMACKey:(NSData*) hmacKey
                HMACType:(TSMACType)hmacType
            matchingHMAC:(NSData *)hmac;
@end

@implementation CryptographyTests


-(void) testLocalDecryption {
    NSString* originalMessage = @"Hawaii is awesome";
    NSString* signalingKeyString = @"VJuRzZcwuY/6VjGw+QSPy5ROzHo8xE36mKwHNvkfyZ+mSPaDlSDcenUqavIX1Vwn\nRRIdrg==";
    NSData* signalingKey = [NSData dataFromBase64String:signalingKeyString];
    XCTAssertTrue([signalingKey length]==52, @"signaling key is not 52 bytes but %llu", (unsigned long long)[signalingKey length]);
    NSData* signalingKeyAESKeyMaterial = [signalingKey subdataWithRange:NSMakeRange(0, 32)];
    NSData* signalingKeyHMACKeyMaterial = [signalingKey subdataWithRange:NSMakeRange(32, 20)];
    NSData* iv = [Cryptography generateRandomBytes:16];
    NSData* version = [Cryptography generateRandomBytes:1];
    NSData* mac;
    
    NSData* encryption = [Cryptography encryptCBCMode:[originalMessage dataUsingEncoding:NSUTF8StringEncoding] withKey:signalingKeyAESKeyMaterial withIV:iv withVersion:version withHMACKey:signalingKeyHMACKeyMaterial withHMACType:TSHMACSHA1Truncated10Bytes computedHMAC:&mac]; //Encrypt
    
    NSMutableData *dataToHmac = [NSMutableData data ];
    [dataToHmac appendData:version];
    [dataToHmac appendData:iv];
    [dataToHmac appendData:encryption];
    
    
    NSData* expectedHmac = [Cryptography truncatedSHA1HMAC:dataToHmac withHMACKey:signalingKeyHMACKeyMaterial truncation:10];
    
    XCTAssertTrue([mac isEqualToData:expectedHmac], @"Hmac of encrypted data %@,  not equal to expected hmac %@", [mac base64EncodedString], [expectedHmac base64EncodedString]);
    
    NSData* decryption=[Cryptography decryptCBCMode:encryption key:signalingKeyAESKeyMaterial IV:iv version:version HMACKey:signalingKeyHMACKeyMaterial HMACType:TSHMACSHA1Truncated10Bytes matchingHMAC:mac];
                        
    NSString* decryptedMessage = [[NSString alloc] initWithData:decryption encoding:NSUTF8StringEncoding];
    XCTAssertTrue([decryptedMessage isEqualToString:originalMessage],  @"Decrypted message: %@ is not equal to original: %@",decryptedMessage,originalMessage);
    
}

@end