Re: [Cryptography] check-summed keys in secret ciphers?

2013-10-05 Thread Phillip Hallam-Baker
On Mon, Sep 30, 2013 at 7:44 PM, arxlight arxli...@arx.li wrote: Just to close the circle on this: The Iranians used hundreds of carpet weavers (mostly women) to reconstruct a good portion of the shredded documents which they published (and I think continue to publish) eventually reaching

Re: [Cryptography] check-summed keys in secret ciphers?

2013-10-03 Thread Philipp G├╝hring
Hi, Am 2013-09-30 10:16, schrieb ianG: I'm not really understanding the need for checksums on keys. Perhaps it is a DLP (Data Leakage Prevention) technology. At least the same method works great for Creditcard numbers. Oh, there is a 14 digit number being sent on a unclassified network, and all

[Cryptography] check-summed keys in secret ciphers?

2013-09-30 Thread ianG
On 29/09/13 16:01 PM, Jerry Leichter wrote: ...e.g., according to Wikipedia, BATON is a block cipher with a key length of 320 bits (160 of them checksum bits - I'd guess that this is an overt way for NSA to control who can use stolen equipment, as it will presumably refuse to operate at all

Re: [Cryptography] check-summed keys in secret ciphers?

2013-09-30 Thread Bill Frantz
On 9/30/13 at 1:16 AM, i...@iang.org (ianG) wrote: Any comments from the wider audience? I talked with a park ranger who had used a high-precision GPS system which decoded the selective availability encrypted signal. Access to the device was very tightly controlled and it had a

Re: [Cryptography] check-summed keys in secret ciphers?

2013-09-30 Thread John Kelsey
GOST was specified with S boxes that could be different for different applications, and you could choose s boxes to make GOST quite weak. So that's one example. --John ___ The cryptography mailing list cryptography@metzdowd.com

Re: [Cryptography] check-summed keys in secret ciphers?

2013-09-30 Thread Jerry Leichter
On Sep 30, 2013, at 4:16 AM, ianG i...@iang.org wrote: I'm not really understanding the need for checksums on keys. I can sort of see the battlefield requirement that comms equipment that is stolen can't then be utilized in either a direct sense (listening in) or re-sold to some other

Re: [Cryptography] check-summed keys in secret ciphers?

2013-09-30 Thread arxlight
On 9/30/13 11:07 PM, Jerry Leichter wrote: On Sep 30, 2013, at 4:16 AM, ianG i...@iang.org wrote: But it still doesn't quite work. It seems antithetical to NSA's obsession with security at Suite A levels, if they are worried about the gear being snatched, they shouldn't have secret

Re: [Cryptography] check-summed keys in secret ciphers?

2013-09-30 Thread Bill Frantz
On 9/30/13 at 2:07 PM, leich...@lrw.com (Jerry Leichter) wrote: People used to wonder why NSA asked that DES keys be checksummed - the original IBM Lucifer algorithm used a full 64-bit key, while DES required parity bits on each byte. On the one hand, this decreased the key size from 64 to