PAYMENT TRANSACTION METHOD AND CORRESPONDING APPLICATIONS

1 . A payment transaction method between a user terminal (TU 1 ; TU 2 ; TU 3 ) registered with a user provider and an agent terminal (TA 1 ; TA 2 ; TA 3 ) registered with an agent provider,

CHARACTERIZED IN THAT prior to sharing transaction details, said user terminal (TU 1 ; TU 2 ; TU 3 ) delegates verification of trust to said user provider and said agent terminal (TA 1 ; TA 2 ; TA 3 ) delegates verification of trust to said agent provider, said user provider and said agent provider having a pre-established trusted relationship.

2 . A payment transaction method according to claim 1 , said method comprising the steps of:

sending a first message ( 102 ; 202 ; 302 ) from said user terminal (TU 1 ; TU 2 ; TU 3 ) to said agent terminal (TA 1 ; TA 2 , TA 3 ) over a distrusted first connection, said first message ( 102 ; 202 ; 302 ) containing a first encrypted portion and a non-encrypted portion comprising a temporary user identification whose usage is restricted to a single payment transaction, and a user provider identification;

authenticating said agent terminal (TA 1 ; TA 2 ; TA 3 ) by an agent provider server (ACSA 1 ; ACSA 2 ; ACSA 3 );

sending a second message ( 103 ; 203 ; 303 ) from said agent terminal (TA 1 ; TA 2 ; TA 3 ) to said agent provider server (ACSA 1 ; ACSA 2 ; ACSA 3 ) over a secure second connection, said second message ( 103 ; 203 ; 303 ) containing said first encrypted portion, said temporary user identification and said user provider identification;

sending a third message ( 104 ; 204 ; 304 ) from said agent provider server (ACSA 1 ; ACSA 2 ; ACSA 3 ) to a user provider server (ACSU 1 ; ACSU 2 ; ACSU 3 ) over a secure third connection, said third message ( 104 ; 204 ; 304 ) comprising said first encrypted portion and said temporary user identification;

decrypting said first encrypted portion by said user provider server (ACSU 1 ; ACSU 2 ; ACSU 3 ) thereby generating decrypted data;

sending a fourth message ( 105 ; 205 ; 305 ) from said user provider server (ACSU 1 ; ACSU 2 ; ACSU 3 ) to said user terminal (TU 1 ; TU 2 ; TU 3 ) over a secure fourth connection, said fourth message ( 105 ; 205 ; 305 ) containing a second encrypted portion comprising at least part of said decrypted data;

decrypting said second encrypted portion by said user terminal (TU 1 ; TU 2 ; TU 3 ) and verifying said at least part of said decrypted data; and

authenticating said transaction by said user provider server (ACSU 1 ; ACSU 2 ; ACSU 3 ).

3 . A payment transaction method according to claim 2 ,

wherein said first message ( 102 ; 202 ; 302 ) further contains information indicative for an amount of money involved in said payment transaction.

4 . A payment transaction method according to claim 2 ,

wherein said second message ( 103 ; 203 ; 303 ) further contains an agent terminal identification.

5 . A payment transaction method according to claim 2 ,

wherein said third message ( 104 ; 204 ; 304 ) further contains location information of said agent terminal (TA 1 ; TA 2 ; TA 3 ); and

wherein authenticating said transaction involves verifying the location of said user terminal (TU 1 ; TU 2 ; TU 3 ) against said location information of said agent terminal (TA 1 ; TA 2 ; TA 3 ).

6 . A payment transaction method according to claim 2 ,

wherein said third message ( 104 ; 204 ; 304 ) further contains business descriptive information of an agent exploiting said agent terminal (TA 1 ; TA 2 ; TA 3 ); and

wherein said fourth message ( 105 ; 205 ; 305 ) further contains said business descriptive information of said agent.

7 . A payment transaction method according to claim 2 ,

wherein said third message ( 104 ; 204 ; 304 ) further contains information indicative for a fee charged by said agent provider on said transaction; and

wherein said fourth message ( 105 ; 205 ; 305 ) further contains information indicative for said fee charged by said agent provider on said transaction and a fee charged by said user provider on said transaction.

8 . A payment transaction method according to claim 2 ,

wherein said first encrypted portion consists of an Identity Based Encryption generated using a public key of said user provider, said Identity Based Encryption further comprising a parameter aP generated by a random number a processed with a public parameter P that represents a known point on a known elliptic curve; and

wherein decrypting said first encrypted portion by said user provider server (ACSU 1 ; ACSU 2 ; ACSU 3 ) involves using a private key of said user provider.

9 . A payment transaction method according to claim 8 ,

wherein said second encrypted portion consists of an Identity Based Encryption generated using a public key of said user, said Identity Based Encryption comprising said parameter aP; and

wherein decrypting said second encrypted portion by said user terminal (TU 1 ; TU 2 ; TU 3 ) involves using a private key of said user for verification to thereby authenticate said user provider server (ACSU 1 ; ACSU 2 ; ACSU 3 ) by said user terminal (TU 1 ; TU 2 ; TU 3 ).

10 . A payment transaction method according to claim 2 ,

wherein said second encrypted portion consists of an identity Based Encryption generated using a public key of said user, said Identity Based Encryption further comprising a parameter bP generated by a random number b processed with a public parameter P that represents a known point on a known elliptic curve; and

decrypting said second encrypted portion by said user terminal (TU 1 ; TU 2 ; TU 3 ) involves using a private key of said user.

11 . A payment transaction method according to claim 9 ,

wherein authenticating said user terminal (TU 1 ; TU 2 ; TU 3 ) by said user provider server (ACSU 1 ; ACSU 2 ; ACSU 3 ) involves:

sending a fifth message ( 106 b ; 206 b ; 306 b ) from said user terminal (TU 1 ; TU 2 ; TU 3 ) to said user provider server (ACSU 1 ; ACSU 2 ; ACSU 3 ), said fifth message ( 106 b ; 206 b ; 306 b ) containing a third encrypted portion consisting of an Identity Based Encryption using a public key of said user provider, said Identity Based Encryption containing said parameter bP; and

decrypting said third encrypted portion by said user provider server (ACSU 1 ; ACSU 2 ; ACSU 3 ) using a private key of said user provider for verification.

12 . A user terminal client application adapted to perform the payment transaction method according to claim 1 .

13 . An agent terminal client application adapted to perform the payment transaction method according to claim 1 .

14 . A user provider server application adapted to perform the payment transaction method according to claim 1 .

15 . An agent provider server application adapted to perform the payment transaction method according to claim 1 .