iOS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  

#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

#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 

#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  

#import <CommonCrypto/CommonDigest.h>   
@interface NSString (MD5)  
- (NSString *)md5Encrypt;  
@end  

 

NSString+MD5.m文件

#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