Devices and methods for simultaneous injection or delivery of two or more substances from separate syringes. The invention relates, in addition, to efficient and scalable processes for the synthesis of various intermediates useful in the synthesis of Fondaparinux and related compounds. An envelope containing a message key is created by encrypting the message key based on a verifier, where the verifier is based on a secret of the recipient. In other embodiments, the imine reduction reaction mixture contains silver tetrafluoroborate.