学步园

//
//  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

//
//  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

#pragma mark - base64
+ (NSString*)encodeBase64String:(NSString *)input;
+ (NSString*)decodeBase64String:(NSString *)input;
+ (NSString*)encodeBase64Data:(NSData *)data;
+ (NSString*)decodeBase64Data:(NSData *)data;

#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;
}

//
//  NSString+MD5Encrypt.h
//  Smile
//
//  Created by 周 敏 on 12-11-24.
//  Copyright (c) 2012年 BOX. All rights reserved.
//

#import <CommonCrypto/CommonDigest.h>

@interface NSString (MD5)

- (NSString *)md5Encrypt;

@end

//
//  NSString+MD5Encrypt.h
//  Smile
//
//  Created by 周 敏 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:@"%02X", result[i]];
    return [hash lowercaseString];
}

@end