A system for secure transfer of encrypted data involves a sender client (36), a recipient client (38), a main server (40), and a key server (42). The sender client (36) receives instructions from a first user identifying transfer data and a recipient identifier, creates an encoding key, encodes the transfer data using the key, and communicates the key and the recipient identifier to a main server (40). The main server (40) communicates the key and the recipient identifier to the key server (42), which associates the recipient identifier with a secure package identifier and communicates the secure package identifier to the main server (40), which communicates the secure package identifier to the sender client (36). The recipient client (38) receives and identifies the secure package identifier and the encoded transfer data, receives from a second user a user identifier, and communicates the user identifier and the secure package identifier to the main server (40), which communicates them to the key server (42). The key server (42) communicates the key to the main server (40) only if the secure package identifier received from the recipient client (38) matches the secure package identifier created by the main server (40) and if the user identifier matches the recipient identifier. The main server (40) communicates the key to the recipient client (38).