关于iOS MD5加密 32位小写 OC代码

#import CommonCrypto/CommonDigest.h 
 + (NSString *)md5:(NSString *)str
 {
 const char *cStr = [str UTF8String];
 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]
 ];
 }