Bcrypt objective-c implementation with a bridging header in swift. This is tested on iOS 9.2.

KKBCrypt.h

//
// KKBCrypt.h
//
// Created by Kadasiddha Kullolli on 11/12/2015.
// Copyright 2015 Kadasiddha Kullolli


#import <Foundation/Foundation.h>

#import "KKGC.h"		// For GC related macros
#import "KKRandom.h"	// For generating random salts


/*
 * The KKBCrypt utility class.
 * This class has been tested to work on iOS 9.2.
 */
@interface KKBCrypt : NSObject {
    
@private
    SInt32 *_p;
    SInt32 *_s;
}

+ (NSString *) hashPassword: (NSString *) password withSalt: (NSString *) salt;
+ (NSString *) generateSaltWithNumberOfRounds: (SInt32) numberOfRounds;

@end

KKBCrypt.m

//
// KKBCrypt.m

//
// Created by Kadasiddha Kullolli on 11/12/2015.
// Copyright 2015 Kadasiddha Kullolli



#import "KKBCrypt.h"


// BCrypt parameters
#define		GENSALT_DEFAULT_LOG2_ROUNDS			10
#define		BCRYPT_SALT_LEN						16

// Blowfish parameters
#define		BLOWFISH_NUM_ROUNDS					16

// Initial contents of key schedule
SInt32 P_orig[] = {
    0x243f6a88, 0x85a308d3, 0x13198a2e, 0x03707344,
    0xa4093822, 0x299f31d0, 0x082efa98, 0xec4e6c89,
    0x452821e6, 0x38d01377, 0xbe5466cf, 0x34e90c6c,
    0xc0ac29b7, 0xc97c50dd, 0x3f84d5b5, 0xb5470917,
    0x9216d5d9, 0x8979fb1b
};

SInt32 S_orig[] = {
    0xd1310ba6, 0x98dfb5ac, 0x2ffd72db, 0xd01adfb7,
    0xb8e1afed, 0x6a267e96, 0xba7c9045, 0xf12c7f99,
    0x24a19947, 0xb3916cf7, 0x0801f2e2, 0x858efc16,
    0x636920d8, 0x71574e69, 0xa458fea3, 0xf4933d7e,
    0x0d95748f, 0x728eb658, 0x718bcd58, 0x82154aee,
    0x7b54a41d, 0xc25a59b5, 0x9c30d539, 0x2af26013,
    0xc5d1b023, 0x286085f0, 0xca417918, 0xb8db38ef,
    0x8e79dcb0, 0x603a180e, 0x6c9e0e8b, 0xb01e8a3e,
    0xd71577c1, 0xbd314b27, 0x78af2fda, 0x55605c60,
    0xe65525f3, 0xaa55ab94, 0x57489862, 0x63e81440,
    0x55ca396a, 0x2aab10b6, 0xb4cc5c34, 0x1141e8ce,
    0xa15486af, 0x7c72e993, 0xb3ee1411, 0x636fbc2a,
    0x2ba9c55d, 0x741831f6, 0xce5c3e16, 0x9b87931e,
    0xafd6ba33, 0x6c24cf5c, 0x7a325381, 0x28958677,
    0x3b8f4898, 0x6b4bb9af, 0xc4bfe81b, 0x66282193,
    0x61d809cc, 0xfb21a991, 0x487cac60, 0x5dec8032,
    0xef845d5d, 0xe98575b1, 0xdc262302, 0xeb651b88,
    0x23893e81, 0xd396acc5, 0x0f6d6ff3, 0x83f44239,
    0x2e0b4482, 0xa4842004, 0x69c8f04a, 0x9e1f9b5e,
    0x21c66842, 0xf6e96c9a, 0x670c9c61, 0xabd388f0,
    0x6a51a0d2, 0xd8542f68, 0x960fa728, 0xab5133a3,
    0x6eef0b6c, 0x137a3be4, 0xba3bf050, 0x7efb2a98,
    0xa1f1651d, 0x39af0176, 0x66ca593e, 0x82430e88,
    0x8cee8619, 0x456f9fb4, 0x7d84a5c3, 0x3b8b5ebe,
    0xe06f75d8, 0x85c12073, 0x401a449f, 0x56c16aa6,
    0x4ed3aa62, 0x363f7706, 0x1bfedf72, 0x429b023d,
    0x37d0d724, 0xd00a1248, 0xdb0fead3, 0x49f1c09b,
    0x075372c9, 0x80991b7b, 0x25d479d8, 0xf6e8def7,
    0xe3fe501a, 0xb6794c3b, 0x976ce0bd, 0x04c006ba,
    0xc1a94fb6, 0x409f60c4, 0x5e5c9ec2, 0x196a2463,
    0x68fb6faf, 0x3e6c53b5, 0x1339b2eb, 0x3b52ec6f,
    0x6dfc511f, 0x9b30952c, 0xcc814544, 0xaf5ebd09,
    0xbee3d004, 0xde334afd, 0x660f2807, 0x192e4bb3,
    0xc0cba857, 0x45c8740f, 0xd20b5f39, 0xb9d3fbdb,
    0x5579c0bd, 0x1a60320a, 0xd6a100c6, 0x402c7279,
    0x679f25fe, 0xfb1fa3cc, 0x8ea5e9f8, 0xdb3222f8,
    0x3c7516df, 0xfd616b15, 0x2f501ec8, 0xad0552ab,
    0x323db5fa, 0xfd238760, 0x53317b48, 0x3e00df82,
    0x9e5c57bb, 0xca6f8ca0, 0x1a87562e, 0xdf1769db,
    0xd542a8f6, 0x287effc3, 0xac6732c6, 0x8c4f5573,
    0x695b27b0, 0xbbca58c8, 0xe1ffa35d, 0xb8f011a0,
    0x10fa3d98, 0xfd2183b8, 0x4afcb56c, 0x2dd1d35b,
    0x9a53e479, 0xb6f84565, 0xd28e49bc, 0x4bfb9790,
    0xe1ddf2da, 0xa4cb7e33, 0x62fb1341, 0xcee4c6e8,
    0xef20cada, 0x36774c01, 0xd07e9efe, 0x2bf11fb4,
    0x95dbda4d, 0xae909198, 0xeaad8e71, 0x6b93d5a0,
    0xd08ed1d0, 0xafc725e0, 0x8e3c5b2f, 0x8e7594b7,
    0x8ff6e2fb, 0xf2122b64, 0x8888b812, 0x900df01c,
    0x4fad5ea0, 0x688fc31c, 0xd1cff191, 0xb3a8c1ad,
    0x2f2f2218, 0xbe0e1777, 0xea752dfe, 0x8b021fa1,
    0xe5a0cc0f, 0xb56f74e8, 0x18acf3d6, 0xce89e299,
    0xb4a84fe0, 0xfd13e0b7, 0x7cc43b81, 0xd2ada8d9,
    0x165fa266, 0x80957705, 0x93cc7314, 0x211a1477,
    0xe6ad2065, 0x77b5fa86, 0xc75442f5, 0xfb9d35cf,
    0xebcdaf0c, 0x7b3e89a0, 0xd6411bd3, 0xae1e7e49,
    0x00250e2d, 0x2071b35e, 0x226800bb, 0x57b8e0af,
    0x2464369b, 0xf009b91e, 0x5563911d, 0x59dfa6aa,
    0x78c14389, 0xd95a537f, 0x207d5ba2, 0x02e5b9c5,
    0x83260376, 0x6295cfa9, 0x11c81968, 0x4e734a41,
    0xb3472dca, 0x7b14a94a, 0x1b510052, 0x9a532915,
    0xd60f573f, 0xbc9bc6e4, 0x2b60a476, 0x81e67400,
    0x08ba6fb5, 0x571be91f, 0xf296ec6b, 0x2a0dd915,
    0xb6636521, 0xe7b9f9b6, 0xff34052e, 0xc5855664,
    0x53b02d5d, 0xa99f8fa1, 0x08ba4799, 0x6e85076a,
    0x4b7a70e9, 0xb5b32944, 0xdb75092e, 0xc4192623,
    0xad6ea6b0, 0x49a7df7d, 0x9cee60b8, 0x8fedb266,
    0xecaa8c71, 0x699a17ff, 0x5664526c, 0xc2b19ee1,
    0x193602a5, 0x75094c29, 0xa0591340, 0xe4183a3e,
    0x3f54989a, 0x5b429d65, 0x6b8fe4d6, 0x99f73fd6,
    0xa1d29c07, 0xefe830f5, 0x4d2d38e6, 0xf0255dc1,
    0x4cdd2086, 0x8470eb26, 0x6382e9c6, 0x021ecc5e,
    0x09686b3f, 0x3ebaefc9, 0x3c971814, 0x6b6a70a1,
    0x687f3584, 0x52a0e286, 0xb79c5305, 0xaa500737,
    0x3e07841c, 0x7fdeae5c, 0x8e7d44ec, 0x5716f2b8,
    0xb03ada37, 0xf0500c0d, 0xf01c1f04, 0x0200b3ff,
    0xae0cf51a, 0x3cb574b2, 0x25837a58, 0xdc0921bd,
    0xd19113f9, 0x7ca92ff6, 0x94324773, 0x22f54701,
    0x3ae5e581, 0x37c2dadc, 0xc8b57634, 0x9af3dda7,
    0xa9446146, 0x0fd0030e, 0xecc8c73e, 0xa4751e41,
    0xe238cd99, 0x3bea0e2f, 0x3280bba1, 0x183eb331,
    0x4e548b38, 0x4f6db908, 0x6f420d03, 0xf60a04bf,
    0x2cb81290, 0x24977c79, 0x5679b072, 0xbcaf89af,
    0xde9a771f, 0xd9930810, 0xb38bae12, 0xdccf3f2e,
    0x5512721f, 0x2e6b7124, 0x501adde6, 0x9f84cd87,
    0x7a584718, 0x7408da17, 0xbc9f9abc, 0xe94b7d8c,
    0xec7aec3a, 0xdb851dfa, 0x63094366, 0xc464c3d2,
    0xef1c1847, 0x3215d908, 0xdd433b37, 0x24c2ba16,
    0x12a14d43, 0x2a65c451, 0x50940002, 0x133ae4dd,
    0x71dff89e, 0x10314e55, 0x81ac77d6, 0x5f11199b,
    0x043556f1, 0xd7a3c76b, 0x3c11183b, 0x5924a509,
    0xf28fe6ed, 0x97f1fbfa, 0x9ebabf2c, 0x1e153c6e,
    0x86e34570, 0xeae96fb1, 0x860e5e0a, 0x5a3e2ab3,
    0x771fe71c, 0x4e3d06fa, 0x2965dcb9, 0x99e71d0f,
    0x803e89d6, 0x5266c825, 0x2e4cc978, 0x9c10b36a,
    0xc6150eba, 0x94e2ea78, 0xa5fc3c53, 0x1e0a2df4,
    0xf2f74ea7, 0x361d2b3d, 0x1939260f, 0x19c27960,
    0x5223a708, 0xf71312b6, 0xebadfe6e, 0xeac31f66,
    0xe3bc4595, 0xa67bc883, 0xb17f37d1, 0x018cff28,
    0xc332ddef, 0xbe6c5aa5, 0x65582185, 0x68ab9802,
    0xeecea50f, 0xdb2f953b, 0x2aef7dad, 0x5b6e2f84,
    0x1521b628, 0x29076170, 0xecdd4775, 0x619f1510,
    0x13cca830, 0xeb61bd96, 0x0334fe1e, 0xaa0363cf,
    0xb5735c90, 0x4c70a239, 0xd59e9e0b, 0xcbaade14,
    0xeecc86bc, 0x60622ca7, 0x9cab5cab, 0xb2f3846e,
    0x648b1eaf, 0x19bdf0ca, 0xa02369b9, 0x655abb50,
    0x40685a32, 0x3c2ab4b3, 0x319ee9d5, 0xc021b8f7,
    0x9b540b19, 0x875fa099, 0x95f7997e, 0x623d7da8,
    0xf837889a, 0x97e32d77, 0x11ed935f, 0x16681281,
    0x0e358829, 0xc7e61fd6, 0x96dedfa1, 0x7858ba99,
    0x57f584a5, 0x1b227263, 0x9b83c3ff, 0x1ac24696,
    0xcdb30aeb, 0x532e3054, 0x8fd948e4, 0x6dbc3128,
    0x58ebf2ef, 0x34c6ffea, 0xfe28ed61, 0xee7c3c73,
    0x5d4a14d9, 0xe864b7e3, 0x42105d14, 0x203e13e0,
    0x45eee2b6, 0xa3aaabea, 0xdb6c4f15, 0xfacb4fd0,
    0xc742f442, 0xef6abbb5, 0x654f3b1d, 0x41cd2105,
    0xd81e799e, 0x86854dc7, 0xe44b476a, 0x3d816250,
    0xcf62a1f2, 0x5b8d2646, 0xfc8883a0, 0xc1c7b6a3,
    0x7f1524c3, 0x69cb7492, 0x47848a0b, 0x5692b285,
    0x095bbf00, 0xad19489d, 0x1462b174, 0x23820e00,
    0x58428d2a, 0x0c55f5ea, 0x1dadf43e, 0x233f7061,
    0x3372f092, 0x8d937e41, 0xd65fecf1, 0x6c223bdb,
    0x7cde3759, 0xcbee7460, 0x4085f2a7, 0xce77326e,
    0xa6078084, 0x19f8509e, 0xe8efd855, 0x61d99735,
    0xa969a7aa, 0xc50c06c2, 0x5a04abfc, 0x800bcadc,
    0x9e447a2e, 0xc3453484, 0xfdd56705, 0x0e1e9ec9,
    0xdb73dbd3, 0x105588cd, 0x675fda79, 0xe3674340,
    0xc5c43465, 0x713e38d8, 0x3d28f89e, 0xf16dff20,
    0x153e21e7, 0x8fb03d4a, 0xe6e39f2b, 0xdb83adf7,
    0xe93d5a68, 0x948140f7, 0xf64c261c, 0x94692934,
    0x411520f7, 0x7602d4f7, 0xbcf46b2e, 0xd4a20068,
    0xd4082471, 0x3320f46a, 0x43b7d4b7, 0x500061af,
    0x1e39f62e, 0x97244546, 0x14214f74, 0xbf8b8840,
    0x4d95fc1d, 0x96b591af, 0x70f4ddd3, 0x66a02f45,
    0xbfbc09ec, 0x03bd9785, 0x7fac6dd0, 0x31cb8504,
    0x96eb27b3, 0x55fd3941, 0xda2547e6, 0xabca0a9a,
    0x28507825, 0x530429f4, 0x0a2c86da, 0xe9b66dfb,
    0x68dc1462, 0xd7486900, 0x680ec0a4, 0x27a18dee,
    0x4f3ffea2, 0xe887ad8c, 0xb58ce006, 0x7af4d6b6,
    0xaace1e7c, 0xd3375fec, 0xce78a399, 0x406b2a42,
    0x20fe9e35, 0xd9f385b9, 0xee39d7ab, 0x3b124e8b,
    0x1dc9faf7, 0x4b6d1856, 0x26a36631, 0xeae397b2,
    0x3a6efa74, 0xdd5b4332, 0x6841e7f7, 0xca7820fb,
    0xfb0af54e, 0xd8feb397, 0x454056ac, 0xba489527,
    0x55533a3a, 0x20838d87, 0xfe6ba9b7, 0xd096954b,
    0x55a867bc, 0xa1159a58, 0xcca92963, 0x99e1db33,
    0xa62a4a56, 0x3f3125f9, 0x5ef47e1c, 0x9029317c,
    0xfdf8e802, 0x04272f70, 0x80bb155c, 0x05282ce3,
    0x95c11548, 0xe4c66d22, 0x48c1133f, 0xc70f86dc,
    0x07f9c9ee, 0x41041f0f, 0x404779a4, 0x5d886e17,
    0x325f51eb, 0xd59bc0d1, 0xf2bcc18f, 0x41113564,
    0x257b7834, 0x602a9c60, 0xdff8e8a3, 0x1f636c1b,
    0x0e12b4c2, 0x02e1329e, 0xaf664fd1, 0xcad18115,
    0x6b2395e0, 0x333e92e1, 0x3b240b62, 0xeebeb922,
    0x85b2a20e, 0xe6ba0d99, 0xde720c8c, 0x2da2f728,
    0xd0127845, 0x95b794fd, 0x647d0862, 0xe7ccf5f0,
    0x5449a36f, 0x877d48fa, 0xc39dfd27, 0xf33e8d1e,
    0x0a476341, 0x992eff74, 0x3a6f6eab, 0xf4f8fd37,
    0xa812dc60, 0xa1ebddf8, 0x991be14c, 0xdb6e6b0d,
    0xc67b5510, 0x6d672c37, 0x2765d43b, 0xdcd0e804,
    0xf1290dc7, 0xcc00ffa3, 0xb5390f92, 0x690fed0b,
    0x667b9ffb, 0xcedb7d9c, 0xa091cf0b, 0xd9155ea3,
    0xbb132f88, 0x515bad24, 0x7b9479bf, 0x763bd6eb,
    0x37392eb3, 0xcc115979, 0x8026e297, 0xf42e312d,
    0x6842ada7, 0xc66a2b3b, 0x12754ccc, 0x782ef11c,
    0x6a124237, 0xb79251e7, 0x06a1bbe6, 0x4bfb6350,
    0x1a6b1018, 0x11caedfa, 0x3d25bdd8, 0xe2e1c3c9,
    0x44421659, 0x0a121386, 0xd90cec6e, 0xd5abea2a,
    0x64af674e, 0xda86a85f, 0xbebfe988, 0x64e4c3fe,
    0x9dbc8057, 0xf0f7c086, 0x60787bf8, 0x6003604d,
    0xd1fd8346, 0xf6381fb0, 0x7745ae04, 0xd736fccc,
    0x83426b33, 0xf01eab71, 0xb0804187, 0x3c005e5f,
    0x77a057be, 0xbde8ae24, 0x55464299, 0xbf582e61,
    0x4e58f48f, 0xf2ddfda2, 0xf474ef38, 0x8789bdc2,
    0x5366f9c3, 0xc8b38e74, 0xb475f255, 0x46fcd9b9,
    0x7aeb2661, 0x8b1ddf84, 0x846a0e79, 0x915f95e2,
    0x466e598e, 0x20b45770, 0x8cd55591, 0xc902de4c,
    0xb90bace1, 0xbb8205d0, 0x11a86248, 0x7574a99e,
    0xb77f19b6, 0xe0a9dc09, 0x662d09a1, 0xc4324633,
    0xe85a1f02, 0x09f0be8c, 0x4a99a025, 0x1d6efe10,
    0x1ab93d1d, 0x0ba5a4df, 0xa186f20f, 0x2868f169,
    0xdcb7da83, 0x573906fe, 0xa1e2ce9b, 0x4fcd7f52,
    0x50115e01, 0xa70683fa, 0xa002b5c4, 0x0de6d027,
    0x9af88c27, 0x773f8641, 0xc3604c06, 0x61a806b5,
    0xf0177a28, 0xc0f586e0, 0x006058aa, 0x30dc7d62,
    0x11e69ed7, 0x2338ea63, 0x53c2dd94, 0xc2c21634,
    0xbbcbee56, 0x90bcb6de, 0xebfc7da1, 0xce591d76,
    0x6f05e409, 0x4b7c0188, 0x39720a3d, 0x7c927c24,
    0x86e3725f, 0x724d9db9, 0x1ac15bb4, 0xd39eb8fc,
    0xed545578, 0x08fca5b5, 0xd83d7cd3, 0x4dad0fc4,
    0x1e50ef5e, 0xb161e6f8, 0xa28514d9, 0x6c51133c,
    0x6fd5c7e7, 0x56e14ec4, 0x362abfce, 0xddc6c837,
    0xd79a3234, 0x92638212, 0x670efa8e, 0x406000e0,
    0x3a39ce37, 0xd3faf5cf, 0xabc27737, 0x5ac52d1b,
    0x5cb0679e, 0x4fa33742, 0xd3822740, 0x99bc9bbe,
    0xd5118e9d, 0xbf0f7315, 0xd62d1c7e, 0xc700c47b,
    0xb78c1b6b, 0x21a19045, 0xb26eb1be, 0x6a366eb4,
    0x5748ab2f, 0xbc946e79, 0xc6a376d2, 0x6549c2c8,
    0x530ff8ee, 0x468dde7d, 0xd5730a1d, 0x4cd04dc6,
    0x2939bbdb, 0xa9ba4650, 0xac9526e8, 0xbe5ee304,
    0xa1fad5f0, 0x6a2d519a, 0x63ef8ce2, 0x9a86ee22,
    0xc089c2b8, 0x43242ef6, 0xa51e03aa, 0x9cf2d0a4,
    0x83c061ba, 0x9be96a4d, 0x8fe51550, 0xba645bd6,
    0x2826a2f9, 0xa73a3ae1, 0x4ba99586, 0xef5562e9,
    0xc72fefd3, 0xf752f7da, 0x3f046f69, 0x77fa0a59,
    0x80e4a915, 0x87b08601, 0x9b09e6ad, 0x3b3ee593,
    0xe990fd5a, 0x9e34d797, 0x2cf0b7d9, 0x022b8b51,
    0x96d5ac3a, 0x017da67d, 0xd1cf3ed6, 0x7c7d2d28,
    0x1f9f25cf, 0xadf2b89b, 0x5ad6b472, 0x5a88f54c,
    0xe029ac71, 0xe019a5e6, 0x47b0acfd, 0xed93fa9b,
    0xe8d3c48d, 0x283b57cc, 0xf8d56629, 0x79132e28,
    0x785f0191, 0xed756055, 0xf7960e44, 0xe3d35e8c,
    0x15056dd4, 0x88f46dba, 0x03a16125, 0x0564f0bd,
    0xc3eb9e15, 0x3c9057a2, 0x97271aec, 0xa93a072a,
    0x1b3f6d9b, 0x1e6321f5, 0xf59c66fb, 0x26dcf319,
    0x7533d928, 0xb155fdf5, 0x03563482, 0x8aba3cbb,
    0x28517711, 0xc20ad9f8, 0xabcc5167, 0xccad925f,
    0x4de81751, 0x3830dc8e, 0x379d5862, 0x9320f991,
    0xea7a90c2, 0xfb3e7bce, 0x5121ce64, 0x774fbe32,
    0xa8b6e37e, 0xc3293d46, 0x48de5369, 0x6413e680,
    0xa2ae0810, 0xdd6db224, 0x69852dfd, 0x09072166,
    0xb39a460a, 0x6445c0dd, 0x586cdecf, 0x1c20c8ae,
    0x5bbef7dd, 0x1b588d40, 0xccd2017f, 0x6bb4e3bb,
    0xdda26a7e, 0x3a59ff45, 0x3e350a44, 0xbcb4cdd5,
    0x72eacea8, 0xfa6484bb, 0x8d6612ae, 0xbf3c6f47,
    0xd29be463, 0x542f5d9e, 0xaec2771b, 0xf64e6370,
    0x740e0d8d, 0xe75b1357, 0xf8721671, 0xaf537d5d,
    0x4040cb08, 0x4eb4e2cc, 0x34d2466a, 0x0115af84,
    0xe1b00428, 0x95983a1d, 0x06b89fb4, 0xce6ea048,
    0x6f3f3b82, 0x3520ab82, 0x011a1d4b, 0x277227f8,
    0x611560b1, 0xe7933fdc, 0xbb3a792b, 0x344525bd,
    0xa08839e1, 0x51ce794b, 0x2f32c9b7, 0xa01fbac9,
    0xe01cc87e, 0xbcc7d1f6, 0xcf0111c3, 0xa1e8aac7,
    0x1a908749, 0xd44fbd9a, 0xd0dadecb, 0xd50ada38,
    0x0339c32a, 0xc6913667, 0x8df9317c, 0xe0b12b4f,
    0xf79e59b7, 0x43f5bb3a, 0xf2d519ff, 0x27d9459c,
    0xbf97222c, 0x15e6fc2a, 0x0f91fc71, 0x9b941525,
    0xfae59361, 0xceb69ceb, 0xc2a86459, 0x12baa8d1,
    0xb6c1075e, 0xe3056a0c, 0x10d25065, 0xcb03a442,
    0xe0ec6e0e, 0x1698db3b, 0x4c98a0be, 0x3278e964,
    0x9f1f9532, 0xe0d392df, 0xd3a0342b, 0x8971f21e,
    0x1b0a7441, 0x4ba3348c, 0xc5be7120, 0xc37632d8,
    0xdf359f8d, 0x9b992f2e, 0xe60b6f47, 0x0fe3f11d,
    0xe54cda54, 0x1edad891, 0xce6279cf, 0xcd3e7e6f,
    0x1618b166, 0xfd2c1d05, 0x848fd2c5, 0xf6fb2299,
    0xf523f357, 0xa6327623, 0x93a83531, 0x56cccd02,
    0xacf08162, 0x5a75ebb5, 0x6e163697, 0x88d273cc,
    0xde966292, 0x81b949d0, 0x4c50901b, 0x71c65614,
    0xe6c6c7bd, 0x327a140a, 0x45e1d006, 0xc3f27b9a,
    0xc9aa53fd, 0x62a80f00, 0xbb25bfe2, 0x35bdd2f6,
    0x71126905, 0xb2040222, 0xb6cbcf7c, 0xcd769c2b,
    0x53113ec0, 0x1640e3d3, 0x38abbd60, 0x2547adf0,
    0xba38209c, 0xf746ce76, 0x77afa1c5, 0x20756060,
    0x85cbfe4e, 0x8ae88dd8, 0x7aaaf9b0, 0x4cf9aa7e,
    0x1948c25c, 0x02fb8a8c, 0x01c36ae4, 0xd6ebe1f9,
    0x90d4f869, 0xa65cdea0, 0x3f09252d, 0xc208e69f,
    0xb74e6132, 0xce77e25b, 0x578fdfe3, 0x3ac372e6
};

// bcrypt IV: "OrpheanBeholderScryDoubt"
SInt32 bf_crypt_ciphertext[] = {
    0x4f727068, 0x65616e42, 0x65686f6c,
    0x64657253, 0x63727944, 0x6f756274
};

// Table for Base64 encoding
NSString *base64_code[] = {
    @".", @"/", @"A", @"B", @"C", @"D", @"E", @"F", @"G", @"H", @"I", @"J",
    @"K", @"L", @"M", @"N", @"O", @"P", @"Q", @"R", @"S", @"T", @"U", @"V",
    @"W", @"X", @"Y", @"Z", @"a", @"b", @"c", @"d", @"e", @"f", @"g", @"h",
    @"i", @"j", @"k", @"l", @"m", @"n", @"o", @"p", @"q", @"r", @"s", @"t",
    @"u", @"v", @"w", @"x", @"y", @"z", @"0", @"1", @"2", @"3", @"4", @"5",
    @"6", @"7", @"8", @"9"
};

// Table for Base64 decoding
signed char index_64[] = {
    -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
    -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
    -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
    -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
    -1, -1, -1, -1, -1, -1, 0, 1, 54, 55,
    56, 57, 58, 59, 60, 61, 62, 63, -1, -1,
    -1, -1, -1, -1, -1, 2, 3, 4, 5, 6,
    7, 8, 9, 10, 11, 12, 13, 14, 15, 16,
    17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27,
    -1, -1, -1, -1, -1, -1, 28, 29, 30,
    31, 32, 33, 34, 35, 36, 37, 38, 39, 40,
    41, 42, 43, 44, 45, 46, 47, 48, 49, 50,
    51, 52, 53, -1, -1, -1, -1, -1
};


@interface KKBCrypt (PrivateMethods)

+ (SInt32 *) integerArrayWithOriginal: (SInt32 *) original ofLength: (SInt32) length;

@end




@implementation KKBCrypt

/*
 * Initializes and returns an autoreleased KKBCrypt instance.
 */
+ (id) bCrypt {
    
    id bCrypt = [[KKBCrypt alloc] init];
    //[bCrypt autorelease];
    
    return bCrypt;
}

/*
 * Releases the receiver's members.
 */
- (void) dealloc {
    
    KKFree(_p);
    KKFree(_s);
    
   //  [super dealloc];
}

/*
 * Encodes an NSData composed of signed chararacters and returns slightly modified Base64 encoded string.
 *
 * Params
 *		data		The data to be encoded.
 *					Passing nil will result in nil being returned.
 *		len			The length.
 *					Must be greater than 0 and no longer than the length of data.
 *
 * Returns
 *		A Base64 encoded string or nil.
 */
+ (NSString *) encodeData: (NSData *) data ofLength: (SInt32) len {
    
    if (data == nil) {
        // Invalid data so return nil.
        return nil;
    }
    
    SInt32 off = 0;
    NSMutableString *rs = [NSMutableString stringWithCapacity: 100];
    SInt32 c1, c2;
    
    if (len <= 0 || len > [data length]) {
        // Invalid length
        return nil;
    }
    
    signed char *d = (signed char *) [data bytes];
    
    while (off < len) {
        c1 = d[off++] & 0xff;
        [rs appendString: base64_code[(c1 >> 2) & 0x3f]];
        c1 = (c1 & 0x03) << 4;
        if (off >= len) {
            [rs appendString: base64_code[c1 & 0x3f]];
            break;
        }
        c2 = d[off++] & 0xff;
        c1 |= (c2 >> 4) & 0x0f;
        [rs appendString: base64_code[c1 & 0x3f]];
        c1 = (c2 & 0x0f) << 2;
        if (off >= len) {
            [rs appendString: base64_code[c1 & 0x3f]];
            break;
        }
        c2 = d[off++] & 0xff;
        c1 |= (c2 >> 6) & 0x03;
        [rs appendString: base64_code[c1 & 0x3f]];
        [rs appendString: base64_code[c2 & 0x3f]];
    }
    
    return rs;
}

/*
 * Returns the Base64 encoded signed character of the provided unicode character.
 *
 * Params
 *		x		The 16-bit unicode character whose Base64 counterpart, if any, will be returned.
 *
 * Returns
 *		The Base64 encoded signed character or -1 if none exists.
 */
+ (signed char) char64of: (unichar) x {
    
    SInt32 xAsInt = (SInt32) x;
    if (xAsInt < 0 || xAsInt > 128 - 1) {
        // The character would go out of bounds of the pre-calculated array so return -1.
        return -1;
    }
    
    // Return the matching Base64 encoded chaacter.
    return index_64[xAsInt];
}


/*
 * Decodes the provided Base64 encoded string to an NSData composed of signed characters.
 *
 * Params
 *		s			The Base64 encoded string.
 *					If this is nil, nil will be returned.
 *		maxolen		The maximum number of characters to decode.
 *					If this is not greater than 0 nil will be returned.
 *
 * Returns
 *		An NSData or nil if the arguments are invalid.
 */
+ (NSData *) decode_base64: (NSString *) s ofMaxLength: (SInt32) maxolen {
    
    if (s == nil) {
        // Invalid string so return nil.
        return nil;
    }
    
    NSMutableString *rs = [NSMutableString stringWithCapacity: 100];
    SInt32 off = 0;
    SInt32 slen = (SInt32) [s length];
    SInt32 olen = 0;
    NSData *ret = nil;
    signed char c1, c2, c3, c4, o;
    
    if (maxolen <= 0) {
        // Invalid number of characters.
        return nil;
    }
    
    while (off < slen - 1 && olen < maxolen) {
        c1 = [KKBCrypt char64of: [s characterAtIndex: off++]];
        c2 = [KKBCrypt char64of: [s characterAtIndex: off++]];
        if (c1 == -1 || c2 == -1) {
            break;
        }
        
        o = (signed char) (c1 << 2);
        o |= (c2 & 0x30) >> 4;
        [rs appendFormat: @"%C", (unichar) o];
        if (++olen >= maxolen || off >= slen) {
            break;
        }
        
        c3 = [KKBCrypt char64of: [s characterAtIndex: off++]];
        if (c3 == -1) {
            break;
        }
        
        o = (signed char) ((c2 & 0x0f) << 4);
        o |= (c3 & 0x3c) >> 2;
        [rs appendFormat: @"%C", (unichar) o];
        if (++olen >= maxolen || off >= slen) {
            break;
        }
        c4 = [KKBCrypt char64of: [s characterAtIndex: off++]];
        o = (signed char) ((c3 & 0x03) << 6);
        o |= c4;
        [rs appendFormat: @"%C", (unichar) o];
        ++olen;
    }
    
    signed char *ret2 = malloc(olen);
    for (off = 0; off < olen; off++) {
        ret2[off] = (signed char) [rs characterAtIndex: off];
    }
    
    ret = [NSData dataWithBytes: ret2 length: olen];
    KKFree(ret2);
    
    return ret;
}


/*
 * Enciphers the provided array using the Blowfish algorithm.
 *
 * Params
 *		lr		The left-right array continaing two 32-bit half blocks.
 *		off		The offset into the array.
 */
- (void) encipher: (SInt32 []) lr off: (SInt32) off {
    
    if (off < 0) {
        // Invalid offset.
        return;
    }
    
    SInt32 i, n, l = lr[off], r = lr[off + 1];
    
    l ^= _p[0];
    for (i = 0; i <= BLOWFISH_NUM_ROUNDS - 2;) {
        // Feistel substitution on left word
        n = _s[(l >> 24) & 0xff];
        n += _s[0x100 | ((l >> 16) & 0xff)];
        n ^= _s[0x200 | ((l >> 8) & 0xff)];
        n += _s[0x300 | (l & 0xff)];
        r ^= n ^ _p[++i];
        
        // Feistel substitution on right word
        n = _s[(r >> 24) & 0xff];
        n += _s[0x100 | ((r >> 16) & 0xff)];
        n ^= _s[0x200 | ((r >> 8) & 0xff)];
        n += _s[0x300 | (r & 0xff)];
        l ^= n ^ _p[++i];
    }
    lr[off] = r ^ _p[BLOWFISH_NUM_ROUNDS + 1];
    lr[off + 1] = l;
}


/*
 * Cycically extracts a word of key material from the provided NSData.
 *
 * Params
 *		d		The NSData from which the word will be extracted.
 *		offp	The "pointer" (as a one-entry array) to the current offset into data.
 *
 * Returns
 *		The next word of material from the data.
 */
+ (SInt32) streamToWord: (NSData *) d off: (SInt32 *) offp {
    
    signed char *data = (signed char *) [d bytes];
    SInt32 dataLength = [d length];
    SInt32 i;
    SInt32 word = 0;
    SInt32 off = offp[0];
    
    for (i = 0; i < 4; i++) {
        word = (word << 8) | (data[off] & 0xff);
        off = (off + 1) % dataLength;
    }
    
    offp[0] = off;
    return word;
}


/*
 * Initializes the blowfish key schedule.
 */
- (void) initKey {
    
    if (_p == nil) {
        _p = [KKBCrypt integerArrayWithOriginal: P_orig
                                       ofLength: 18];
    }
    
    if (_s == nil) {
        _s = [KKBCrypt integerArrayWithOriginal: S_orig
                                       ofLength: 1024];
    }
}


/*
 * Returns an integer array copied from the provided one.
 * NOTE: It is the caller's responsibility to free the array.
 *
 * Params
 *		original		The original integer array.
 *		length			The length to copy.
 *
 * Returns
 *		The copied array.
 */
+ (SInt32 *) integerArrayWithOriginal: (SInt32 *) original ofLength: (SInt32) length {
    
    SInt32 *copied = malloc(sizeof(SInt32) * length);
    
    for (SInt32 loop = 0; loop < length; loop++) {
        copied[loop] = original[loop];
    }
    
    return copied;
}


/*
 * Keys the receiver's blowfish cipher using the provided key.
 *
 * Params
 *		key		The array containing the key.
 */
- (void) key: (NSData *) key {
    
    SInt32 i;
    SInt32 koffp[] = {0};
    SInt32 lr[] = {0, 0};
    SInt32 plen = 18;
    SInt32 slen = 1024;
    
    for (i = 0; i < plen; i++) {
        _p[i] = _p[i] ^ [KKBCrypt streamToWord: key off: koffp];
    }
    
    for (i = 0; i < plen; i += 2) {
        [self encipher: lr off: 0];
        _p[i] = lr[0];
        _p[i + 1] = lr[1];
    }
    
    for (i = 0; i < slen; i += 2) {
        [self encipher: lr off: 0];
        _s[i] = lr[0];
        _s[i + 1] = lr[1];
    }
}


/*
 * Params
 *		data		The salt data.
 *		key			The password data.
 */
- (void) enhanceKeyScheduleWithData: (NSData *) data key: (NSData *) key {
    
    SInt32 i;
    SInt32 koffp[] = {0}, doffp[] = {0};
    SInt32 lr[] = {0, 0};
    SInt32 plen = 18;
    SInt32 slen = 1024;
    
    for (i = 0; i < plen; i++) {
        _p[i] = _p[i] ^ [KKBCrypt streamToWord: key off: koffp];
    }
    
    for (i = 0; i < plen; i += 2) {
        lr[0] ^= [KKBCrypt streamToWord: data off: doffp];
        lr[1] ^= [KKBCrypt streamToWord: data off: doffp];
        [self encipher: lr off: 0];
        _p[i] = lr[0];
        _p[i + 1] = lr[1];
    }
    
    for (i = 0; i < slen; i += 2) {
        lr[0] ^= [KKBCrypt streamToWord: data off: doffp];
        lr[1] ^= [KKBCrypt streamToWord: data off: doffp];
        [self encipher: lr off: 0];
        _s[i] = lr[0];
        _s[i + 1] = lr[1];
    }
}


/*
 * Hashes the provided password with the salt for the number of rounds.
 *
 * Params
 *		password		The password to hash.
 *		salt			The salt to use in the hash.
 *						Must be 16 characters in length.
 *		numberOfRounds	The number of rounds to apply.
 *						Must be between 4 and 31.
 *
 * Returns
 *		The hashed password.
 */
- (NSData *) hashPassword: (NSData *) password withSalt: (NSData *) salt rounds: (SInt32) numberOfRounds {
    
    SInt32 rounds, i, j;
    SInt32 *cdata = [KKBCrypt integerArrayWithOriginal: bf_crypt_ciphertext
                                              ofLength: 6];
    
    SInt32 clen = 6;
    signed char *ret;
    
    if (numberOfRounds < 4 || numberOfRounds > 31) {
        // Invalid number of rounds
        KKFree(cdata);
        return nil;
    }
    
    rounds = 1 << numberOfRounds;
    if ([salt length] != BCRYPT_SALT_LEN) {
        // Invalid salt length
        KKFree(cdata);
        return nil;
    }
    
    [self initKey];
    [self enhanceKeyScheduleWithData: salt
                                 key: password];
    
    for (i = 0; i < rounds; i++) {
        [self key: password];
        [self key: salt];
    }
    
    for (i = 0; i < 64; i++) {
        for (j = 0; j < (clen >> 1); j++) {
            [self encipher: cdata off: j << 1];
        }
    }
    
    ret = malloc(clen * 4);
    for (i = 0, j = 0; i < clen; i++) {
        ret[j++] = (signed char) ((cdata[i] >> 24) & 0xff);
        ret[j++] = (signed char) ((cdata[i] >> 16) & 0xff);
        ret[j++] = (signed char) ((cdata[i] >> 8) & 0xff);
        ret[j++] = (signed char) (cdata[i] & 0xff);
    }
    
    NSData *val = [NSData dataWithBytes: ret
                                 length: clen * 4];
    KKFree(ret);
    KKFree(cdata);
    
    return val;
}


/*
 * Hashes the provided password with the salt.
 *
 * Params
 *		password		The password to hash.
 *		salt			The salt to use in the hash.
 *						Must be 16 characters in length.
 *
 * Returns
 *		The hashed password.
 */
+ (NSString *) hashPassword: (NSString *) password withSalt: (NSString *) salt {
    
    KKBCrypt *bCrypt = nil;
    NSString *realSalt;
    NSData *passwordData;
    NSData *saltData;
    NSData *hashedData;
    unichar minor = (unichar) 0;
    SInt32 rounds, off = 0;
    NSMutableString *hashedPassword = [NSMutableString stringWithCapacity: 100];
    
    if ([salt characterAtIndex: 0] != '$' || [salt characterAtIndex: 1] != '2') {
        // Invalid salt version.
        return nil;
    }
    
    if ([salt characterAtIndex: 2] == '$') {
        off = 3;
    } else {
        minor = [salt characterAtIndex: 2];
        if (minor != 'a' || [salt characterAtIndex: 3] != '$') {
            // Invalid salt revision.
            return nil;
        }
        off = 4;
    }
    
    // Extract number of rounds
    if ([salt characterAtIndex: off + 2] > '$') {
        // Missing salt rounds
        return nil;
    }
    
    NSRange range = NSMakeRange(off, 2);
    rounds = [[salt substringWithRange: range] integerValue];
    
    range = NSMakeRange(off + 3, (off + 25) - (off + 3));
    realSalt = [salt substringWithRange: range];
    
    NSString *passwordPreEncodingToData = [password stringByAppendingString: (minor >= 'a' ? @"\000" : @"")];
    passwordData = [passwordPreEncodingToData dataUsingEncoding: NSUTF8StringEncoding];
    
    saltData = [KKBCrypt decode_base64: realSalt
                           ofMaxLength: BCRYPT_SALT_LEN];
    
    bCrypt = [KKBCrypt bCrypt];
    hashedData = [bCrypt hashPassword: passwordData
                             withSalt: saltData
                               rounds: rounds];
    
    [hashedPassword appendString: @"$2"];
    if (minor >= 'a') {
        [hashedPassword appendFormat: @"%C", minor];
    }
    
    [hashedPassword appendString: @"$"];
    if (rounds < 10) {
        [hashedPassword appendString: @"0"];
    }
    
    [hashedPassword appendFormat: @"%d", (int)rounds];
    [hashedPassword appendString: @"$"];
    [hashedPassword appendString: [KKBCrypt encodeData: saltData
                                              ofLength: [saltData length]]];
    [hashedPassword appendString: [KKBCrypt encodeData: hashedData
                                              ofLength: 23]];
    
    return hashedPassword;
}


/*
 * Generates a salt with the provided number of rounds.
 *
 * Params
 *		numberOfRounds		The number of rounds to apply.
 *							The work factor increases exponentially.
 *
 * Returns
 *		The generated salt.
 */
+ (NSString *) generateSaltWithNumberOfRounds: (SInt32) numberOfRounds {
    
    NSMutableString *salt = [NSMutableString stringWithCapacity: BCRYPT_SALT_LEN];
    NSData *randomData = [KKRandom generateRandomSignedDataOfLength: BCRYPT_SALT_LEN];
    
    [salt appendString: @"$2a$"];
    if (numberOfRounds < 10) {
        [salt appendString: @"0"];
    }
    
    [salt appendFormat: @"%d", (int)numberOfRounds];
    [salt appendString: @"$"];
    [salt appendString: [KKBCrypt encodeData: randomData
                                    ofLength: [randomData length]]];
    
    return salt;
}

@end

KKGC.h

//
// KKGC.h
//
// Created by Kadasiddha Kullolli on 11/12/2015.
// Copyright 2015 Kadasiddha Kullolli

#if __has_feature(objc_arc)

#define KKAssign(to, from) { to = from; }
#define KKRelease(a) { a = nil; }
#define KKFree(a) { free(a); a = NULL; }

#else

/*
 * The KKAssign macro assigns the value of one object reference to another.
 */
#define KKAssign(to, from) { id __temp__ = from; KKRelease(to); to = [__temp__ retain]; }

/*
 * The KKRelease macro releases an objective C object using the release method.
 * If the object reference is nil nothing will be released.
 * The object reference is then assigned to nil.
 */
#define KKRelease(a) { id __temp__ = a; [__temp__ release]; a = nil; }

/*
 * The KKFree macro releases a non-objective C memory buffer using the free function.
 * If the pointer is nil nothing will be freed.
 * The pointer is then assigned to nil.
 */
#define KKFree(a) { free(a); a = NULL; }

#endif

KKRandom.h

//
// KKRandom.h
//
// Created by Kadasiddha Kullolli on 11/12/2015.
// Copyright 2015 Kadasiddha Kullolli


#import <Foundation/Foundation.h>


/*
 * Utility class for generating random data.
 */
@interface KKRandom : NSObject

+ (BOOL) generateNumberBetweenLow: (NSInteger) low andHigh: (NSInteger) high intoReceiver: (NSInteger *) receiver;
+ (BOOL) generateNumberSequenceOfLength: (NSUInteger) length into: (NSInteger[]) sequence betweenLow: (NSInteger) low andHigh: (NSInteger) high withOnlyUniqueValues: (BOOL) onlyUniqueValues;
+ (BOOL) chooseNumberFromSequence: (NSInteger[]) sequence ofLength: (NSUInteger) length intoReceiver: (NSInteger *) receiver;
+ (BOOL) isNumber: (NSInteger) number inSequence: (NSInteger[]) sequence ofLength: (NSUInteger) length;
+ (NSData *) generateRandomSignedDataOfLength: (NSUInteger) length;
+ (NSData *) generateRandomDataOfLength: (NSUInteger) length;
+ (NSString *) generateRandomStringOfLength: (NSUInteger) length;
+ (NSString *) generateRandomStringOfLength: (NSUInteger) length withOnlyCharacters: (NSString *) characters;

+ (NSDate *) generateRandomDateBetweenDaysAgo: (NSInteger)daysAgo andDaysFromNow: (NSInteger)daysFromNow;

@end

KKRandom.m

//
// KKRandom.m
//
// Created by Kadasiddha Kullolli on 11/12/2015.
// Copyright 2015 Kadasiddha Kullolli

#import "KKRandom.h"


@implementation KKRandom

/*
 * Generates a random number between low and high and places it into the receiver.
 *
 * Params
 *		low			The low number.
 *					Must be lower or equal to high.
 *		high		The high number.
 *					Must be equal or higher than low.
 *		receiver	The receiver for the random number.
 *					Must not be nil.
 *
 * Return
 *		YES if successful, NO otherwise.
 */
+ (BOOL) generateNumberBetweenLow: (NSInteger) low andHigh: (NSInteger) high intoReceiver: (NSInteger *) receiver {
    
    if (low > high) {
        return NO;
    }
    
    if (receiver == nil) {
        return NO;
    }
    
    *receiver = (arc4random() % ((high + 1) - low)) + low;
    return YES;
}

/*
 * Generates an optionally unique sequence of random numbers between low and high and places them into the sequence.
 *
 * Params
 *		length				The length of the sequence.
 *							Must be at least 1.
 *		sequence			The receiving sequence.
 *							Must not be nil and must accomodate at least 'length' numbers.
 *		low					The low number.
 *							Must be lower or equal to high.
 *		high				The high number.
 *							Must be equal or higher than low.
 *		onlyUniqueValues	YES if only unique values are to be generated, NO otherwise.
 *
 * Return
 *		YES if successful, NO otherwise.
 */
+ (BOOL) generateNumberSequenceOfLength: (NSUInteger) length into: (NSInteger[]) sequence betweenLow: (NSInteger) low andHigh: (NSInteger) high withOnlyUniqueValues: (BOOL) onlyUniqueValues {
    
    if (length < 1) {
        return NO;
    }
    
    if (sequence == nil) {
        return NO;
    }
    
    if (low > high) {
        return NO;
    }
    
    if (onlyUniqueValues && length > (high - low) + 1) {
        return NO;
    }
    
    NSInteger number;
    
    if (onlyUniqueValues) {
        for (NSUInteger loop = 0; loop < length; loop++) {
            // Only unique values are allowed.
            if (![KKRandom generateNumberBetweenLow: low
                                            andHigh: high
                                       intoReceiver: &number]) {
                return NO;
            }
            
            if ([KKRandom isNumber: number
                        inSequence: sequence
                          ofLength: loop]) {
                // This is not a unique number so skip adding it to the sequence.
                loop--;
                continue;
            } else {
                // This is a unique number so add it to the sequence.
                sequence[loop] = number;
            }
        }
    } else {
        // Repetitive values are allowed.
        for (NSUInteger loop = 0; loop < length; loop++) {
            // Only unique values are allowed.
            if (![KKRandom generateNumberBetweenLow: low
                                            andHigh: high
                                       intoReceiver: &number]) {
                return NO;
            }
            
            sequence[loop] = number;
        }
    }
    
    return YES;
}

/*
 * Randomly chooses a number from the provided sequence and places it into the receiver.
 *
 * Params
 *		sequence	The receiving sequence.
 *					Must not be nil and must be of at least 'length' numbers.
 *		length		The length of the sequence.
 *					Must be at least 1.
 *		receiver	The receiver for the random number.
 *					Must not be nil.
 *
 * Return
 *		YES if successful, NO otherwise.
 */
+ (BOOL) chooseNumberFromSequence: (NSInteger[]) sequence ofLength: (NSUInteger) length intoReceiver: (NSInteger *) receiver {
    
    if (length < 1) {
        return NO;
    }
    
    if (sequence == nil) {
        return NO;
    }
    
    if (receiver == nil) {
        return NO;
    }
    
    NSInteger number;
    
    // Generate a random index into the sequence...
    if (![KKRandom generateNumberBetweenLow: 0
                                    andHigh: length - 1
                               intoReceiver: &number]) {
        return NO;
    }
    
    *receiver = sequence[number];
    return YES;
}

/*
 * Returns YES if the provided number appears within the sequence.
 *
 * Params
 *		number		The number to test.
 *		sequence	The sequence within which to test.
 *					Must not be nil and must be of at least 'length' numbers.
 *		length		The length of the sequence.
 *					Must be at least 1.
 *
 * Return
 *		YES if the number was found, NO otherwise.
 */
+ (BOOL) isNumber: (NSInteger) number inSequence: (NSInteger[]) sequence ofLength: (NSUInteger) length {
    
    if (length < 1) {
        return NO;
    }
    
    if (sequence == nil) {
        return NO;
    }
    
    for (NSUInteger check = 0; check < length; check++) {
        
        if (sequence[check] == number) {
            // The number was found so return YES.
            return YES;
        }
    }
    
    // The number was not found.
    return NO;
}

/*
 * Returns an NSData populated with bytes whose values range from 0 to 255.
 *
 * Params
 *		length		The length of the resulting NSData.
 *					Must be 1 or greater or nil will be returned.
 *
 * Returns
 *		An NSData instance containing random bytes.
 */
+ (NSData *) generateRandomDataOfLength: (NSUInteger) length {
    
    if (length == 0) {
        return nil;
    }
    
    NSInteger *sequence = malloc(sizeof(NSInteger) * length);
    [KKRandom generateNumberSequenceOfLength: length
                                        into: sequence
                                  betweenLow: 0
                                     andHigh: 255
                        withOnlyUniqueValues: NO];
    
    char *randData = malloc(length);
    for (NSUInteger loop = 0; loop < length; loop++) {
        randData[loop] = (char) sequence[loop];
    }
    
    free(sequence);
    NSData *data = [NSData dataWithBytes: randData
                                  length: length];
    free(randData);
    
    return data;
}

/*
 * Returns an NSData populated with bytes whose values range from -128 to 127.
 *
 * Params
 *		length		The length of the resulting NSData.
 *					Must be 1 or greater or nil will be returned.
 *
 * Returns
 *		An NSData instance containing random signed bytes.
 */
+ (NSData *) generateRandomSignedDataOfLength: (NSUInteger) length {
    
    if (length == 0) {
        return nil;
    }
    
    NSInteger *sequence = malloc(sizeof(NSInteger) * length);
    [KKRandom generateNumberSequenceOfLength: length
                                        into: sequence
                                  betweenLow: -128
                                     andHigh: 127
                        withOnlyUniqueValues: NO];
    
    signed char *randData = malloc(length);
    for (NSUInteger loop = 0; loop < length; loop++) {
        randData[loop] = (signed char) sequence[loop];
    }
    
    free(sequence);
    NSData *data = [NSData dataWithBytes: randData
                                  length: length];
    free(randData);
    
    return data;
}

/*
 *
 * Returns a string populated with random characters.
 *
 * Params
 *		length		The length of the resulting string.
 *					Must be 1 or greater or nil will be returned.
 *
 * Returns
 *		An ASCII encoded NSString instance.
 */
+ (NSString *) generateRandomStringOfLength: (NSUInteger) length {
    
    if (length == 0) {
        return nil;
    }
    
    NSInteger *sequence = malloc(sizeof(NSInteger) * length);
    [KKRandom generateNumberSequenceOfLength: length
                                        into: sequence
                                  betweenLow: 0
                                     andHigh: 255
                        withOnlyUniqueValues: NO];
    
    char *randData = malloc(length);
    for (NSUInteger loop = 0; loop < length; loop++) {
        randData[loop] = (char) sequence[loop];
    }
    
    free(sequence);
    NSString *string = [NSString stringWithCString: randData
                                          encoding: NSASCIIStringEncoding];
    free(randData);
    
    return string;
}

/*
 *
 * Returns a string populated with random characters.
 *
 * Params
 *		length		The length of the resulting string.
 *					Must be 1 or greater or nil will be returned.
 *      characters  The valid ASCII characters to include in the output.
 *
 * Returns
 *		An ASCII encoded NSString instance.
 */
+ (NSString *) generateRandomStringOfLength: (NSUInteger) length withOnlyCharacters: (NSString *) characters {
    
    if (length == 0) {
        return nil;
    }
    
    NSUInteger charactersLength = [characters length];
    if (charactersLength == 0) {
        return [KKRandom generateRandomStringOfLength: length];
    }
    
    
    
    NSInteger *sequence = malloc(sizeof(NSInteger) * length);
    [KKRandom generateNumberSequenceOfLength: length
                                        into: sequence
                                  betweenLow: 0
                                     andHigh: charactersLength - 1
                        withOnlyUniqueValues: NO];
    
    const char *cc = [characters cStringUsingEncoding: NSASCIIStringEncoding];
    char *randData = malloc(length + 1);
    for (NSUInteger loop = 0; loop < length; loop++) {
        NSUInteger s = sequence[loop];
        randData[loop] = cc[s];
    }
    randData[length] = 0;
    
    free(sequence);
    NSString *string = [NSString stringWithCString: randData
                                          encoding: NSASCIIStringEncoding];
    free(randData);
    
    return string;
}

/*
 * Returns a random date between daysAgo and daysFromNow relative to today.
 *
 * Params
 *      daysAgo
 *      daysFromNow   
 *
 * Returns
 *      NSDate within the range
 */
+ (NSDate *) generateRandomDateBetweenDaysAgo: (NSInteger) daysAgo andDaysFromNow: (NSInteger) daysFromNow {
    
    NSInteger range = daysFromNow + daysAgo;
    
    NSDateComponents *startDay = [[NSDateComponents alloc] init] ;
    startDay.day = -daysAgo;
    
    NSCalendar *calendar = [NSCalendar currentCalendar];
    
    NSDate *date = [NSDate date];
    date = [calendar dateByAddingComponents: startDay
                                     toDate: date
                                    options: 0];
    
    NSDateComponents *offsetDays = [[NSDateComponents alloc] init] ;
    offsetDays.day = arc4random() % range;
    
    date = [calendar dateByAddingComponents: offsetDays
                                     toDate: date
                                    options: 0];
    
    return date;
}

@end