IOS开发之----常用加密方法（AES、MD5、Base64）

1、AES加密

NSData+AES.h文件

//

// NSData-AES.h

// Smile

//

// Created by Gary on 12-11-24.

// Copyright (c) 2012年 BOX. All rights reserved.

//

#import

@class NSString;

@interface NSData (Encryption)

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

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

@end

NSData+AES.m文件

//

// NSData-AES.h

// Smile

//

// Created by Gary on 12-11-24.

// Copyright (c) 2012年 BOX. All rights reserved.

//

#import "NSData+AES.h"

#import

@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

#pragma mark - base64

+ (NSString*)encodeBase64String:(NSString *)input;

+ (NSString*)decodeBase64String:(NSString *)input;

+ (NSString*)encodeBase64Data:(NSData *)data;

+ (NSString*)decodeBase64Data:(NSData *)data;

.m文件

#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*)decodeBase64String:(NSString * )input {

NSData *data = [input dataUsingEncoding:NSUTF8StringEncoding allowLossyConversion:YES];

data = [GTMBase64 decodeData:data];

NSString *base64String = [[[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding] autorelease];

return base64String;

}

+ (NSString*)encodeBase64Data:(NSData *)data {

data = [GTMBase64 encodeData:data];

NSString *base64String = [[[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding] autorelease];

return base64String;

}

+ (NSString*)decodeBase64Data:(NSData *)data {

data = [GTMBase64 decodeData:data];

NSString *base64String = [[[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding] autorelease];

return base64String;

}

3、MD5加密

NSString+MD5.h文件

//

// NSString+MD5Encrypt.h

// Smile

//

// Created by Gary on 12-11-24.

// Copyright (c) 2012年 BOX. All rights reserved.

//

#import

@interface NSString (MD5)

- (NSString *)md5Encrypt;

@end

NSString+MD5.m文件

//

// NSString+MD5Encrypt.h

// Smile

//

// Created by Gary on 12-11-24.

// Copyright (c) 2012年 BOX. All rights reserved.

//

#import "NSString+MD5.h"

@implementation NSString (MD5)

- (NSString *)md5Encrypt {

const char *original_str = [self 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 < 16; i++)

[hash appendFormat:@"X", result[i]];

return [hash lowercaseString];

}

@end

demo含有这3种的使用方式，在AppDelegate.m文件里面，不会使用的自己参考一下。
http://download.csdn.net/detail/p709723778/4974339