#import <CommonCrypto/CommonDigest.h>

@implementation MD5Util

+(NSString *)encode:(NSString *)value{

[value retain];

const char *cStr = [value UTF8String];

[value release];

    unsigned char result[16];

    CC_MD5( cStr, strlen(cStr), result ); // This is the md5 call

    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]

];  

}

@end

iOS 中使用md5加密