System, device, and method of transaction verification based on challenge and response messages
Computerized method for verification of user identity and transaction data authenticity, usable in systems having an electronic device that communicates with a remote server. The method includes: (a) receiving user interactions at a non-secure execution environment of the electronic device, reflecting transaction data entered by a user; and transmitting transaction data from the non-secure execution environment to the server; (b) locally authenticating the transaction data and user identity in a secure execution environment of the electronic device; and encrypting transaction data in that secure execution environment, by utilizing a Cryptographic Private Key of the electronic device as encryption key; and transmitting encrypted version of locally-authenticated transaction data from the electronic device to the server. Then, at the server: (c1) receiving the transaction data that was sent in step (a) from the non-secure execution environment to the server, and delaying transaction execution until arrival and verification processing of the encrypted version; (c2) receiving the encrypted version, and decrypting it by utilizing a Cryptographic Public Key of the electronic device as decryption key; (c3) checking whether or not transaction data obtained in step (c1), match transaction data obtained in step (c2); and if they do no match, then: generating a signal that voids or cancels the transaction.
1 . A computerized method for verification of user identity and transaction data authenticity,
wherein the computerized method is implementable m a system that comprises an electronic device that communicates with a remote server,
wherein the electronic device comprises: a first hardware processor that is configured to execute code, and a first memory unit that is configured to store code and data;
wherein the remote server comprises: a second hardware processor that is configured to execute code, and a second memory unit that is configured to store code and data;
wherein the computerized method comprises:
(a) at the electronic device:
receiving user inputs from a user that enters transaction data;
securely authenticating said user via a biometric authentication process;
securely storing the transaction data in a secure memory unit within the electronic device;
securely storing, in said secure memory unit within the electronic device, a transaction time-stamp;
transmitting the transaction data to the remote server;
(b) at the remote server:
receiving the transaction data from the electronic device;
pseudo-randomly generating a cryptographic nonce, and storing it in the remote server as a server-side copy of the cryptographic nonce;
generating a Server-Side Challenge Message, by encrypting (i) the cryptographic nonce and (ii) the transaction data and (iii) a current time-stamp, with a Cryptographic Public Key of said electronic device as encryption key;
transmitting the Server-Side Challenge Message to the electronic device;
(c) at the electronic device:
receiving the Server-Side Challenge Message;
decrypting the Server-Side Challenge Message, by utilizing a Cryptographic Private Key of said electronic device as a decryption key, to generate a decrypted version of the Server-Side Challenge Message;
extracting from the decrypted version of the Server-Side Challenge Message: (i) the cryptographic nonce, and (ii) the time-stamp that was stored within the Server-Side Challenge Message, and (iii) the transaction data that was stored within the Server-Side Challenge Message;
locating a relevant transaction based on the time-stamp that was extracted from the decrypted version of the Server-Side Challenge Message;
(d) at the electronic device:
checking whether the transaction data, that was stored within the Server-Side Challenge Message, matches the transaction data that was locally stored in the secure memory unit within the electronic device when said transaction data was entered;
and if it does not match, then: generating a signal that voids or cancels the transaction;
(e) at the electronic device:
checking whether the time-stamp, that was stored within the Server-Side Challenge Message, matches the transaction time-stamp that was locally stored in the secure memory unit within the electronic device when said transaction data was entered;
and if it does not match, then: generating a signal that voids or cancels the transaction;
(f) at the electronic device:
generating a Client-Side Response Message, by encrypting the cryptographic nonce that was extracted in step (c) from the decrypted version of the Server-Side Challenge Message, with the Cryptographic Private Key of said electronic device as an encryption key;
transmitting the Client-Side Response Message from said electronic device to said remote server;
(g) at the remote server:
receiving the Client-Side Response Message from said electronic device;
decrypting the Client-Side Response Message from said electronic device, by utilizing the Cryptographic Public Key of said electronic device as decryption key, to generate a decrypted version of the Client-Side Response Message;
checking whether (i) a value of the cryptographic nonce that is extracted from the decrypted version of the Client-Side Response Message, matches (ii) the server-side copy of the cryptographic nonce;
and if it does not match, then: generating a signal that voids or cancels the transaction.
2 . The computerized method of claim 1 ,
wherein step (a) comprises:
at said electronic device, securely authenticating said user via a biometric authentication process that includes at least capturing a video segment of the user while the user enters the transaction data into said electronic device, and utilizing one or more signals or data-items extracted from said video segment to authenticate said user.
3 . A computerized system for verification of user identity and transaction data authenticity,
wherein the computerized system comprises an electronic device that communicates with a remote server;
wherein the electronic device comprises: a first hardware processor that is configured to execute code, and a first memory unit that is configured to store code and data;
wherein the remote server comprises: a second hardware processor that is configured to execute code, and a second memory unit that is configured to store code and data;
wherein the computerized system is configured to perform a process comprising:
(a) at the electronic device:
receiving user inputs from a user that enters transaction data;
securely authenticating said user via a biometric authentication process;
securely storing the transaction data in a secure memory unit within the electronic device;
securely storing, in said secure memory unit within the electronic device, a transaction time-stamp;
transmitting the transaction data to the remote server;
(b) at the remote server:
receiving the transaction data from the electronic device;
pseudo-randomly generating a cryptographic nonce, and storing it in the remote server as a server-side copy of the cryptographic nonce;
generating a Server-Side Challenge Message, by encrypting (i) the cryptographic nonce and (ii) the transaction data and (iii) a current time-stamp, with a Cryptographic Public Key of said electronic device as encryption key;
transmitting the Server-Side Challenge Message to the electronic device;
(c) at the electronic device:
receiving the Server-Side Challenge Message;
decrypting the Server-Side Challenge Message, by utilizing a Cryptographic Private Key of said electronic device as a decryption key, to generate a decrypted version of the Server-Side Challenge Message;
extracting from the decrypted version of the Server-Side Challenge Message: (i) the cryptographic nonce, and (ii) the time-stamp that was stored within the Server-Side Challenge Message, and (iii) the transaction data that was stored within the Server-Side Challenge Message;
locating a relevant transaction based on the time-stamp that was extracted from the decrypted version of the Server-Side Challenge Message;
(d) at the electronic device:
checking whether the transaction data, that was stored within the Server-Side Challenge Message, matches the transaction data that was locally stored in the secure memory unit within the electronic device when said transaction data was entered; and if it does not match, then: generating a signal that voids or cancels the transaction;
(e) at the electronic device:
checking whether the time-stamp, that was stored within the Server-Side Challenge Message, matches the transaction time-stamp that was locally stored in the secure memory unit within the electronic device when said transaction data was entered; and if it does not match, then: generating a signal that voids or cancels the transaction;
(f) at the electronic device:
generating a Client-Side Response Message, by encrypting the cryptographic nonce that was extracted in step (c) from the decrypted version of the Server-Side Challenge Message, with the Cryptographic Private Key of said electronic device as an encryption key;
transmitting the Client-Side Response Message from said electronic device to said remote server;
(g) at the remote server:
receiving the Client-Side Response Message from said electronic device; decrypting the Client-Side Response Message from said electronic device, by utilizing the Cryptographic Public Key of said electronic device as decryption key, to generate a decrypted version of the Client-Side Response Message;
checking whether (i) a value of the cryptographic nonce that is extracted from the decrypted version of the Client-Side Response Message, matches (ii) the server-side copy of the cryptographic nonce;
and if it does not match, then: generating a signal that voids or cancels the transaction.