MD5加密，Base64加密/解密，AES加密/解密

1.从github上下载GTMBase64-master和AESCrypt-ObjC-master导入工程，如下图所示。

2.使用前的配置及注意事项：

（1）在build phases中的GTMBase64.m需要设置 -fno-objc-arc

（2）在#import "NSString+Base64.m”文件中导入 #import <Foundation/Foundation.h>

（3）在#import "GTMBase64.m”文件中添加 #import <CommonCrypto/CommonCrypto.h>

3. CusMD5.h 和 CusMD5.m 文件

#import <Foundation/Foundation.h>
 
@interface CusMD5 : NSObject
 
+ (NSString *)md5String:(NSString *)str;
 
@end
 
#import "CusMD5.h"
#import <CommonCrypto/CommonDigest.h>
 
@implementation CusMD5
 
+ (NSString *)md5String:(NSString *)str {
    const char *original_str = [str UTF8String];
    unsigned char result[CC_MD5_DIGEST_LENGTH];
    CC_MD5(original_str, strlen(original_str), result);
    NSMutableString *hash = [NSMutableString string];
    for (int i = 0; i < CC_MD5_DIGEST_LENGTH; i++)
        [hash appendFormat:@"%02X", result[i]];
    return [hash lowercaseString]; }
 
@end

　　 ---> MD5只能称为一种不可逆的加密算法，只能用作一些检验过程，不能恢复其原文。

4. 基本使用

#import "ViewController.h"
#import "CusMD5.h"
#import "GTMBase64.h"
#import "AESCrypt.h"
 
@interface ViewController ()
 
@end
 
@implementation ViewController
 
- (void)viewDidLoad {
    [super viewDidLoad];
 
    //要加密的字符串
    NSString *strForEn = @"需要加密字符串";
     
    //md5加密
    NSString *strEnRes = [CusMD5 md5String:strForEn];
    NSLog(@"md5 加密: %@",strEnRes);
     
    //base64加密
    NSData *dataEn = [strForEn dataUsingEncoding:NSUTF8StringEncoding];
    NSData *dataEnRes = [GTMBase64 encodeData:dataEn];
    //把加密结果转成string
    NSString *base64EnRes = [[NSString alloc] initWithData:dataEnRes encoding:NSUTF8StringEncoding];
    NSLog(@"base64加密: %@",base64EnRes);
     
    //base64解密
    NSData *resDeBase64 = [GTMBase64 decodeData:dataEnRes];
    NSString *strDeBase64 = [[NSString alloc] initWithData:resDeBase64 encoding:NSUTF8StringEncoding];
    NSLog(@"base64解密: %@",strDeBase64);
 
 
    //aes 加密
    NSString *strAESEnRes = [AESCrypt encrypt:strForEn password:@"secret"];
    NSLog(@"aes 加密: %@",strAESEnRes);
     
    //aes 解密
    NSString *strAESDeRes = [AESCrypt decrypt:strAESEnRes password:@"secret"];
    NSLog(@"aes 解密: %@",strAESDeRes);
}
 
- (void)didReceiveMemoryWarning {
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}
 
@end