Signal-iOS/SignalServiceKit/tests/Devices/OWSProvisioningCipherTest.m

//
// Copyright 2017 Signal Messenger, LLC
// SPDX-License-Identifier: AGPL-3.0-only
//

#import "SSKBaseTestObjC.h"
#import <Curve25519Kit/Curve25519.h>
#import <SignalCoreKit/Cryptography.h>
#import <SignalServiceKit/SignalServiceKit-Swift.h>

@interface OWSProvisioningCipher(Testing)

// Expose private method for testing.
- (instancetype)initWithTheirPublicKey:(NSData *)theirPublicKey
                            ourKeyPair:(ECKeyPair *)ourKeyPair
                  initializationVector:(NSData *)initializationVector;

@end

@interface OWSProvisioningCipherTest : SSKBaseTestObjC

@end

@implementation OWSProvisioningCipherTest

- (NSData *)knownInitializationVector
{
    uint8_t initilizationVectorBytes[] = {
        0xec, 0x67, 0x0b, 0xb7,
        0x18, 0xe1, 0xe9, 0x0a,
        0xcc, 0x5e, 0xcb, 0x37,
        0xab, 0x79, 0xe0, 0x09
    };
    return [NSData dataWithBytes:initilizationVectorBytes length:16];
}

- (NSData *)knownPublicKey
{
    uint8_t knownPublicKeyBytes[] = {
        0x5e, 0x23, 0xe8, 0x49,
        0xb2, 0x23, 0x21, 0xdb,
        0x2e, 0x3a, 0x77, 0x74,
        0x6f, 0x3b, 0x44, 0x18,
        0xcc, 0x6c, 0x81, 0xce,
        0xd5, 0xc2, 0x91, 0xaf,
        0xed, 0xfb, 0x21, 0x4e,
        0x59, 0xcc, 0x19, 0xa4
    };
    return [NSData dataWithBytes:knownPublicKeyBytes length: 32];
}

- (ECKeyPair *)knownKeyPair
{
    uint8_t privateKeyBytes[] = {
        0x60, 0xfd, 0xc1, 0xeb,
        0x6a, 0x68, 0x3d, 0x2b,
        0x51, 0x23, 0x1f, 0xea,
        0x1a, 0x5e, 0x80, 0x88,
        0x0c, 0x65, 0x2d, 0x3d,
        0x47, 0x9e, 0x28, 0xc1,
        0x9f, 0x48, 0x2c, 0x66,
        0xde, 0x48, 0x5d, 0x57
    };

    uint8_t publicKeyBytes[] = {
        0x02, 0x62, 0x7b, 0x5c,
        0x21, 0x15, 0x59, 0x1b,
        0x37, 0xd1, 0xfe, 0xeb,
        0x15, 0x5d, 0xd2, 0x95,
        0x0a, 0xce, 0xe8, 0xb2,
        0x1e, 0x8e, 0xc8, 0xd6,
        0x53, 0x4f, 0x1a, 0xcd,
        0xf2, 0x00, 0x98, 0x32
    };

    // Righteous hack to build a deterministic ECKeyPair
    // The publicKey/privateKey ivars are private but it's possible to `initWithCoder:` given the proper keys.
    NSKeyedArchiver *archiver = [NSKeyedArchiver new];
    [archiver encodeBytes:publicKeyBytes length:ECCKeyLength forKey:@"TSECKeyPairPublicKey"];
    [archiver encodeBytes:privateKeyBytes length:ECCKeyLength forKey:@"TSECKeyPairPrivateKey"];

    NSData *serialized = [archiver encodedData];
    NSKeyedUnarchiver *unarchiver = [[NSKeyedUnarchiver alloc] initForReadingWithData:serialized];
    return [[ECKeyPair alloc] initWithCoder:unarchiver];
}

- (NSData *)knownData
{
    uint8_t knownBytes[] = {
        0x19, 0x33, 0x78, 0x64,
        0x96, 0x56, 0xa7, 0xd0,
        0x6e, 0xff, 0x37, 0x1d
    };
    
    return [NSData dataWithBytes:knownBytes length:12];
}

- (void)testEncrypt
{
    NSData *theirPublicKey = [self knownPublicKey];
    ECKeyPair *ourKeyPair = [self knownKeyPair];
    NSData *initializationVector = [self knownInitializationVector];
    
    OWSProvisioningCipher *cipher = [[OWSProvisioningCipher alloc] initWithTheirPublicKey:theirPublicKey
                                                                               ourKeyPair:ourKeyPair
                                                                     initializationVector:initializationVector];
    
    NSData *message = [self knownData];
    NSData *actualOutput = [cipher encrypt:message];
    
    uint8_t expectedBytes[] = {
        0x01, 0xec, 0x67, 0x0b,
        0xb7, 0x18, 0xe1, 0xe9,
        0x0a, 0xcc, 0x5e, 0xcb,
        0x37, 0xab, 0x79, 0xe0,
        0x09, 0xf7, 0x2b, 0xf7,
        0x14, 0x3d, 0x45, 0xd7,
        0x45, 0x79, 0x1e, 0x4f,
        0x9d, 0x34, 0x8a, 0x2d,
        0x43, 0x64, 0xd4, 0x7d,
        0x48, 0x9a, 0xdc, 0x5a,
        0xc3, 0x72, 0xfa, 0x63,
        0x41, 0x7a, 0xa8, 0x45,
        0x36, 0xe9, 0xc5, 0xcb,
        0xee, 0x9b, 0xc1, 0x1f,
        0xec, 0x31, 0x1e, 0xc2,
        0x33, 0x2d, 0x95, 0x54,
        0xcc
    };
    NSData *expectedOutput = [NSData dataWithBytes:expectedBytes length:65];
    
    XCTAssertEqualObjects(expectedOutput, actualOutput);
}

- (void)testPadding
{
    NSUInteger kBlockSize = 16;
    for (int i = 0; i <= kBlockSize; i++) {
        NSData *message = [Cryptography generateRandomBytes:i];


        NSData *theirPublicKey = [self knownPublicKey];
        ECKeyPair *ourKeyPair = [self knownKeyPair];
        NSData *initializationVector = [self knownInitializationVector];

        OWSProvisioningCipher *cipher = [[OWSProvisioningCipher alloc] initWithTheirPublicKey:theirPublicKey
                                                                                   ourKeyPair:ourKeyPair
                                                                         initializationVector:initializationVector];


        NSData *actualOutput = [cipher encrypt:message];
        XCTAssertNotNil(actualOutput, @"failed for message length: %d", i);
    }
}

@end