Address encryption method for flash memories
View Patent ↗An electronic memory component provides a plurality of access-secured sub-areas. Each access-secured memory sub-area has at least one assigned parameter, for example, an address. The memory encrypts the assigned parameters of the access-secured sub-areas in such a way that on the one hand the security of such devices is increased considerably and on the other hand the associated expense and technical complexity are not too great. The encryption allows access to at least one sub-area dependent on at least one further sub-area.
1. A data processing device, comprising an electronic memory component, the data processing device comprising:
an encryption block, said encryption block receiving an address comprised of a series of parameters a 0 , . . . , a n and applying an encryption method on at least one parameter to produce an encrypted series of parameters a′ 0 , . . . , a′ n according to the series:
a
j
′
=
{
f
n
-
j
+
1
(
a
j
)
j
=
n
f
n
-
j
+
1
(
a
j
+
f
n
-
j
(
a
j
+
1
)
)
j
=
0
,
…
,
n
-
1
wherein encryption function ƒ j+1 and encryption function ƒ j are distinct for all values of j, and
for at least a first parameter in said series of parameters, a′ x ≠a x and for at least a second parameter in said series of parameters, a′ y =a y where 0≦x≦j and 0≦y≦j.
2. The data processing device as claimed in claim 1 , wherein the memory component comprises:
an erasable programmable read only memory,
an electrically erasable programmable read only memory or
a flash memory.
3. The data processing device of claim 1 , wherein the data processing device is utilized in at least one of:
a one smart card controller,
a reader integrated circuit,
a cryptography chipset, or
for application in at least one of audio or video encryption.
4. A method of securing access to an electronic memory, comprising:
receiving, by a data processing device, an address comprised of a series of parameters a 0 , . . . , a n ; and
encrypting, by said data processing device, at least one of said parameters with an encryption method, to produce an encrypted series of parameters a′ 0 , . . . , a′ n according to the series:
a
j
′
=
{
f
n
-
j
+
1
(
a
j
)
j
=
n
f
n
-
j
+
1
(
a
j
+
f
n
-
j
(
a
j
+
1
)
)
j
=
0
,
…
,
n
-
1
wherein encryption function ƒ j+1 and encryption function ƒ j are distinct for all values of j, and
for at least a first parameter in said series of parameters, a′ x ≠a x and for at least a second parameter in said series of parameters, a′ y =a y where 0≦x≦j and 0≦y≦j.
5. The method as claimed in claim 4 , characterized in that the function is one-to-one, according to the equation
a′ 0 =ƒ n+1 ( a 0 +ƒ n ( a 1 +ƒ n−1 ( a 2 + . . . +ƒ 1 ( a n )))).