5 ms·Is sms channel really secure? Isn't it a plain text channel, as opposed to an unencrypted channel?by ybaumes 12y agoIs sms channel really secure? Isn't it a plain text channel, as opposed to an unencrypted channel?yuvadam 12y agoSMS is encrypted on GSM control channels using the broken A5/1 stream cipher which has well-known weaknesses.anaphor 12y agoand the base station can _disable_ encryption completely without any warning given to the cellphone user.