iOS开发（93）之常用加密方法（aes、md5、base64）

iOS常用加密方法（aes、md5、base64）

1、AES加密
NSData+AES.h文件

[plain] //
// NSData-AES.h
// Smile
//
// Created by 周敏 on 12-11-24.
// Copyright (c) 2012年 BOX. All rights reserved.
//

#import <Foundation/Foundation.h>

@class NSString;

@interface NSData (Encryption)

- (NSData *)AES256EncryptWithKey:(NSString *)key; //加密
- (NSData *)AES256DecryptWithKey:(NSString *)key; //解密

@end

NSData+AES.m文件
[plain] //
// NSData-AES.h
// Smile
//
// Created by 周敏 on 12-11-24.
// Copyright (c) 2012年 BOX. All rights reserved.
//

#import "NSData+AES.h"
#import <CommonCrypto/CommonCryptor.h>

@implementation NSData (Encryption)

- (NSData *)AES256EncryptWithKey:(NSString *)key {//加密
    char keyPtr[kCCKeySizeAES256+1];
    bzero(keyPtr, sizeof(keyPtr));
    [key getCString:keyPtr maxLength:sizeof(keyPtr) encoding:NSUTF8StringEncoding];
    NSUInteger dataLength = [self length];
    size_t bufferSize = dataLength + kCCBlockSizeAES128;
    void *buffer = malloc(bufferSize);
    size_t numBytesEncrypted = 0;
    CCCryptorStatus cryptStatus = CCCrypt(kCCEncrypt, kCCAlgorithmAES128,
                                          kCCOptionPKCS7Padding | kCCOptionECBMode,
                                          keyPtr, kCCBlockSizeAES128,
                                          NULL,
                                          [self bytes], dataLength,
                                          buffer, bufferSize,
                                          &numBytesEncrypted);
    if (cryptStatus == kCCSuccess) {
        return [NSData dataWithBytesNoCopy:buffer length:numBytesEncrypted];
    }
    free(buffer);
    return nil;
}

- (NSData *)AES256DecryptWithKey:(NSString *)key {//解密
    char keyPtr[kCCKeySizeAES256+1];
    bzero(keyPtr, sizeof(keyPtr));
    [key getCString:keyPtr maxLength:sizeof(keyPtr) encoding:NSUTF8StringEncoding];
    NSUInteger dataLength = [self length];
    size_t bufferSize = dataLength + kCCBlockSizeAES128;
    void *buffer = malloc(bufferSize);
    size_t numBytesDecrypted = 0;
    CCCryptorStatus cryptStatus = CCCrypt(kCCDecrypt, kCCAlgorithmAES128,
                                          kCCOptionPKCS7Padding | kCCOptionECBMode,
                                          keyPtr, kCCBlockSizeAES128,
                                          NULL,
                                          [self bytes], dataLength,
                                          buffer, bufferSize,
                                          &numBytesDecrypted);
    if (cryptStatus == kCCSuccess) {
        return [NSData dataWithBytesNoCopy:buffer length:numBytesDecrypted];
    }
    free(buffer);
    return nil;
}

@end
这里AES在iOS加过密以后以nsdata的形式存下来，如果想以nsstring形式存储，那么对nsdata进行base64位编码。
2、BASE64编码
首先下载GTMBase64文件，在工程中加入三个文件
GTMDefines.h
GTMBase64.h
GTMBase64.m
你可以在这里找到这三个文件
http://code.google.com/p/google-toolbox-for-mac/source/browse/trunk/Foundation/?r=87
你也可以在下面的demo里面找到这3个文件，demo会完整实现文章里面常用的3种编码方法。
我在此稍微封装一下：

.h文件
[plain] #pragma mark - base64
+ (NSString*)encodeBase64String:(NSString *)input;
+ (NSString*)decodeBase64String:(NSString *)input;
+ (NSString*)encodeBase64Data:(NSData *)data;
+ (NSString*)decodeBase64Data:(NSData *)data;

.m文件
[plain] #pragma mark - base64
+ (NSString*)encodeBase64String:(NSString * )input {
    NSData *data = [input dataUsingEncoding:NSUTF8StringEncoding allowLossyConversion:YES];
    data = [GTMBase64 encodeData:data];
    NSString *base64String = [[[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding] autorelease];
    return base64String;
}

+ (NSString*)decodeBase64Strin

补充：移动开发 , IOS ,