iOS基础：加密

一、base64加密

//base64编码- (NSString *)base64Encode:(NSString *)str {    NSData *data = [str dataUsingEncoding:NSUTF8StringEncoding];    return [data base64EncodedStringWithOptions:0];}

//base64解码- (NSString *)base64Decode:(NSString *)str {    NSData *data = [[NSData alloc] initWithBase64EncodedString:str options:0];    return [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding];}