Suggestion: detect network version when loading private key from WIF into a BTCKey

[crazyquark]

I made a category for BTCKey that automatically detect the network the wallet is for; use if you find it useful:

#import <CoreBitcoin/BTCKey.h>

#import "BTCAddressBcyTestnet.h"

@interface BTCKey (BcyTestnet)

@property(nonatomic, readonly) BTCPublicKeyAddressBcyTestnet* addressByNetwork;

- (id) initWithWIF:(NSString*)wifString detectNetwork:(BOOL)detect;

@end


#import <CoreBitcoin/BTCData.h>
#import <CoreBitcoin/BTCBase58.h>

#import "BTCKey+BcyTestnet.h"

@implementation BTCKey (BcyTestnet)

uint8_t version;

- (id) initWithWIF:(NSString*)wifString detectNetwork:(BOOL)detect {
    if (!detect) {
        return [self initWithWIF:wifString];
    }
    
    const char* addressString = [wifString cStringUsingEncoding:NSASCIIStringEncoding];
    
    NSMutableData* composedData = BTCDataFromBase58CheckCString(addressString);
    if (!composedData) return nil;
    if (composedData.length < 2) return nil;
    
    // TODO: unsafe
    version = ((unsigned char*)composedData.bytes)[0];
    
    BTCPrivateKeyAddress* addr = [BTCPrivateKeyAddress addressWithString:wifString];
    if (![addr isKindOfClass:[BTCPrivateKeyAddress class]]) {
        return nil;
    }
    return [self initWithPrivateKeyAddress:addr];
}

- (BTCAddress*) addressByNetwork {
    NSData* pubkey = [self publicKey];
    
    // TODO: could cache this value but meh...
    if (version == BTCBcyPrivateKeyAddressVersion) {
        return [BTCPublicKeyAddressBcyTestnet addressWithData:BTCHash160(pubkey)];
    } else if (version == BTCBcyPrivateKeyAddressVersion) {
        return [BTCPrivateKeyAddressTestnet addressWithData:BTCHash160(pubkey)];
    } else {
        return [BTCPrivateKeyAddress addressWithData:BTCHash160(pubkey)];
    }
}

@end

[crazyquark]

Sorry for the bad formatting

[crazyquark]

I also created this class to support the BlockCypher testnet:

#import <CoreBitcoin/BTCAddress.h>

enum {
    BTCBcyAddressVersion = 27,
    BTCBcyPrivateKeyAddressVersion = 73
};

@interface BTCPublicKeyAddressBcyTestnet : BTCPublicKeyAddressTestnet

@end

@interface BTCPrivateKeyAddressBcyTestnet : BTCPrivateKeyAddressTestnet

@end

#import "BTCAddressBcyTestnet.h"

@implementation BTCPublicKeyAddressBcyTestnet

+ (void) load {
    [BTCAddress registerAddressClass:self version:[self BTCVersionPrefix]];
}

+ (uint8_t) BTCVersionPrefix {
    return BTCBcyAddressVersion;
}

@end

@implementation BTCPrivateKeyAddressBcyTestnet

+ (void) load {
    [BTCAddress registerAddressClass:self version:[self BTCVersionPrefix]];
}

+ (uint8_t) BTCVersionPrefix {
    return BTCBcyPrivateKeyAddressVersion;
}

@end