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Received: from sigma.offblast.org ([199.191.58.44]) by pp; Mon Apr 27 14:50:05 EDT 2015
Date: Mon, 27 Apr 2015 14:49:57 -0400
From: mischief@9.offblast.org
To: counter@9.offblast.org, mode@9.offblast.org, goof", 9front@9front.org
Subject: "AES
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i was looking at aes counter mode code recently. in
/sys/src/libsec/port/aes.c i don't see any code that initializes
or modifies AESstate->ctrsz. ctrsz is passed to
/sys/src/libsec/port/aes.c:/^incrementCTR which is supposed to
increment the counter. since ctrsz is always 0, i think it doesn't work
the way it is intended to.

i also think the code

	mpctrsz = itomp(1 << (ctrsz*8), nil);

is wrong, because any ctrsz > 3 will make the integer shift to a value
larger than signed 32 bit integer, and make itomp behave in strange ways,
resulting in incorrect modulo of the aes counter.