ios MD5 encrypted 32-bit (case sensitive)

#import "NSString+change.h"  
#import <CommonCrypto/CommonDigest.h>  
@implementation NSString (change)  
//小写
- (NSString*)md532BitLower  
{  
    const char *cStr = [self UTF8String];  
    unsigned char result[16];  

    NSNumber *num = [NSNumber numberWithUnsignedLong:strlen(cStr)];  
    CC_MD5( cStr,[num intValue], result );  

    return [[NSString stringWithFormat:  
             @"%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X",  
             result[0], result[1], result[2], result[3],  
             result[4], result[5], result[6], result[7],  
             result[8], result[9], result[10], result[11],  
             result[12], result[13], result[14], result[15]  
             ] lowercaseString];  
}  
//大写
- (NSString*)md532BitUpper  
{  
    const char *cStr = [self UTF8String];  
    unsigned char result[16];  

    NSNumber *num = [NSNumber numberWithUnsignedLong:strlen(cStr)];  
    CC_MD5( cStr,[num intValue], result );  

    return [[NSString stringWithFormat:  
             @"%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X",  
             result[0], result[1], result[2], result[3],  
             result[4], result[5], result[6], result[7],  
             result[8], result[9], result[10], result[11],  
             result[12], result[13], result[14], result[15]  
             ] uppercaseString];  
}  
@end