[REQUEST] RSA claims 33 and 37 of U.S. patent 4,405,829

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2 total messages Started by Robert Cain Thu, 01 Oct 1992 19:22

#109

Author: Robert Cain
Date: Thu, 01 Oct 1992 19:22

42 lines
1981 bytes

The patent contains as claim 33:

	In a communication system an encoding means for transforming a
	transmit message word signal M to a ciphertext word signal C
	where M corresponds to a number representative of a message and

		0 <= M <= n-1

	where n is a composite number and where C corresponds to a number
	representative of an enciphered form of said message and corresponds
	to

		C = a[e]*M^e + a[e-1]*M^(e-1) + ... a[0](mod n)

	where e and a[e], a[e-1], ... a[0] are numbers.

Claim 37 is nearly identical except that cryptographic use is specifically
claimed.

Thus it appears that any cryptographic method using a polynomial modulo
a composite infringes.  I am seeking opinions, particularly from any
legal experts that may read this as to whether this claim which essentially
claims the use of a single mathematical formula is defensable?

Further I would like to know if anyone is aware of any prior art (filing
was Dec. 14, 1977) using a polynomial as simple as C = M^2(mod n) even that 
would invalidate this claim.

Thanks,

Bob
-- 
Bob Cain    rcain@netcom.com   408-358-2007

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Re: [REQUEST] RSA claims 33 and 37 of U.S. patent 4,405,829

#97

Author: Gregory J. Kirsch
Date: Fri, 09 Oct 1992 16:35

37 lines
2157 bytes

In <1992Oct6.223005.8776@cs.su.oz.au> rcain@netcom.com (Robert Cain) writes:

>The patent contains as claim 33:

>	In a communication system an encoding means for transforming a
>	transmit message word signal M to a ciphertext word signal C
>	where M corresponds to a number representative of a message and

>		0 <= M <= n-1

>	where n is a composite number and where C corresponds to a number
>	representative of an enciphered form of said message and corresponds
>	to

>		C = a[e]*M^e + a[e-1]*M^(e-1) + ... a[0](mod n)

>	where e and a[e], a[e-1], ... a[0] are numbers.

>Claim 37 is nearly identical except that cryptographic use is specifically
>claimed.

>Thus it appears that any cryptographic method using a polynomial modulo
>a composite infringes.  I am seeking opinions, particularly from any
>legal experts that may read this as to whether this claim which essentially
>claims the use of a single mathematical formula is defensable?

Claim 33, as it is written above, is presumably not a valid claim, and should
not have been allowed by the patent examiner.  Assuming that the claim above
is written exactly how it appears in the patent, it does not comport to
35 USC 112(6), which essentially requires that claims in "Means-plus-function"
language must include a combination of elements.  In the case of claim 33
above, there appears to be only one means: the "means for transforming...".
This means is the only element recited in the claim.

Therefore, regardless of whether the claim recites patentable subject matter,
the claim is not proper.

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