md5加密

#import <Foundation/Foundation.h>

//进行校验和缓存

@interface NSString(MD5Addition)

- (NSString *) stringFromMD5;

@end

#import "NSString+MD5Addition.h"

#import <CommonCrypto/CommonDigest.h>

@implementation NSString(MD5Addition)

- (NSString *) stringFromMD5{

    

    if(self == nil || [self length] == 0)

        return nil;

    

    const char *value = [self UTF8String];

    

    unsigned char outputBuffer[CC_MD5_DIGEST_LENGTH];

    CC_MD5(value, strlen(value), outputBuffer);

    

    NSMutableString *outputString = [[NSMutableString alloc] initWithCapacity:CC_MD5_DIGEST_LENGTH * 2];

    for(NSInteger count = 0; count < CC_MD5_DIGEST_LENGTH; count++){

        [outputString appendFormat:@"%02x",outputBuffer[count]];

    }

    

    return outputString;

}

@end