IOS 数据加密方式（加盐，MD5加密，）

加密方式封装

@interface NSString (Hash)

@property (readonly) NSString *md5String;
@property (readonly) NSString *sha1String;
@property (readonly) NSString *sha256String;
@property (readonly) NSString *sha512String;

- (NSString *)hmacSHA1StringWithKey:(NSString *)key;
- (NSString *)hmacSHA256StringWithKey:(NSString *)key;
- (NSString *)hmacSHA512StringWithKey:(NSString *)key;

@end

#import "NSString+hash.h"

#import <CommonCrypto/CommonDigest.h>
#import <CommonCrypto/CommonHMAC.h>

@implementation NSString (Hash)

- (NSString *)md5String
{
    const char *string = self.UTF8String;
    int length = (int)strlen(string);
    unsigned char bytes[CC_MD5_DIGEST_LENGTH];
    CC_MD5(string, length, bytes);
    return [self stringFromBytes:bytes length:CC_MD5_DIGEST_LENGTH];
}

- (NSString *)sha1String
{
    const char *string = self.UTF8String;
    int length = (int)strlen(string);
    unsigned char bytes[CC_SHA1_DIGEST_LENGTH];
    CC_SHA1(string, length, bytes);
    return [self stringFromBytes:bytes length:CC_SHA1_DIGEST_LENGTH];
}

- (NSString *)sha256String
{
    const char *string = self.UTF8String;
    int length = (int)strlen(string);
    unsigned char bytes[CC_SHA256_DIGEST_LENGTH];
    CC_SHA256(string, length, bytes);
    return [self stringFromBytes:bytes length:CC_SHA256_DIGEST_LENGTH];
}

- (NSString *)sha512String
{
    const char *string = self.UTF8String;
    int length = (int)strlen(string);
    unsigned char bytes[CC_SHA512_DIGEST_LENGTH];
    CC_SHA512(string, length, bytes);
    return [self stringFromBytes:bytes length:CC_SHA512_DIGEST_LENGTH];
}

- (NSString *)hmacSHA1StringWithKey:(NSString *)key
{
    NSData *keyData = [key dataUsingEncoding:NSUTF8StringEncoding];
    NSData *messageData = [self dataUsingEncoding:NSUTF8StringEncoding];
    NSMutableData *mutableData = [NSMutableData dataWithLength:CC_SHA1_DIGEST_LENGTH];
    CCHmac(kCCHmacAlgSHA1, keyData.bytes, keyData.length, messageData.bytes, messageData.length, mutableData.mutableBytes);
    return [self stringFromBytes:(unsigned char *)mutableData.bytes length:mutableData.length];
}

- (NSString *)hmacSHA256StringWithKey:(NSString *)key
{
    NSData *keyData = [key dataUsingEncoding:NSUTF8StringEncoding];
    NSData *messageData = [self dataUsingEncoding:NSUTF8StringEncoding];
    NSMutableData *mutableData = [NSMutableData dataWithLength:CC_SHA256_DIGEST_LENGTH];
    CCHmac(kCCHmacAlgSHA256, keyData.bytes, keyData.length, messageData.bytes, messageData.length, mutableData.mutableBytes);
    return [self stringFromBytes:(unsigned char *)mutableData.bytes length:mutableData.length];
}

- (NSString *)hmacSHA512StringWithKey:(NSString *)key
{
    NSData *keyData = [key dataUsingEncoding:NSUTF8StringEncoding];
    NSData *messageData = [self dataUsingEncoding:NSUTF8StringEncoding];
    NSMutableData *mutableData = [NSMutableData dataWithLength:CC_SHA512_DIGEST_LENGTH];
    CCHmac(kCCHmacAlgSHA512, keyData.bytes, keyData.length, messageData.bytes, messageData.length, mutableData.mutableBytes);
    return [self stringFromBytes:(unsigned char *)mutableData.bytes length:mutableData.length];
}

#pragma mark - Helpers

- (NSString *)stringFromBytes:(unsigned char *)bytes length:(int)length
{
    NSMutableString *mutableString = @"".mutableCopy;
    for (int i = 0; i < length; i++)
        [mutableString appendFormat:@"%02x", bytes[i]];
    return [NSString stringWithString:mutableString];
}

@end

#import "HMViewController.h"
#import "NSString+Hash.h"

#define Salt @"fsdhjkfhjksdhjkfjhkd546783765"

@interface HMViewController ()

@end

@implementation HMViewController

- (void)viewDidLoad
{
    [super viewDidLoad];
    
    [self digest4:@"123"]; //
    
    
    [self digest4:@"abc"];
    [self digest4:@"456"];
}

/**
 *  直接用MD5加密
 */
- (NSString *)digest:(NSString *)str
{
    NSString *anwen = [str md5String];
    NSLog(@"%@ - %@", str, anwen);
    return anwen;
}

/**
 *  加盐
 */
- (NSString *)digest2:(NSString *)str
{
    str = [str stringByAppendingString:Salt];
    
    NSString *anwen = [str md5String];
    NSLog(@"%@ - %@", str, anwen);
    return anwen;
}

/**
 *  多次MD5
 */
- (NSString *)digest3:(NSString *)str
{
    NSString *anwen = [str md5String];
    
    anwen = [anwen md5String];
    
    NSLog(@"%@ - %@", str, anwen);
    return anwen;
}

/**
 *  先加密, 后乱序
 */
- (NSString *)digest4:(NSString *)str
{
    NSString *anwen = [str md5String];
    
    // 注册:  123 ----  2CB962AC59075B964B07152D234B7020
    
    // 登录: 123 --- 202CB962AC59075B964B07152D234B70
    
    NSString *header = [anwen substringToIndex:2];
    NSString *footer = [anwen substringFromIndex:2];
    
    anwen = [footer stringByAppendingString:header];
    
    
    NSLog(@"%@ - %@", str, anwen);
    
    return anwen;
}

@end