[maemo-users] Support for Crypto engine in OMAP/OMAP2 processors

From: Dongi maemo at la.mine.nu
Date: Tue Oct 9 00:02:30 EEST 2007
On 5 October 2007, david.hagood at gmail.com <david.hagood at gmail.com> wrote:
> Does anybody know if any work is being done to make the crypto engine in
> the OMAP/OMAP2 processors available under Linux?

Texas Instruments does not release technical information except for
their paying customers. Nokia probably knows how to access the crypto
engine but they must be under some kind of NDA.

These crypto API are extremely light and can be very easily reverse
engineered if you have an example. Certicom seems to be the crypto
library provider for the OMAP2420 chip. This library can be extracted
from any development platform which uses the TI chip, like the N95 Nokia
phone or the H4 symbian development boards. Once you get hold of one
binary just disassemble it in IDA Pro 5.1 (which has the ARM11
instruction set) and search for the crypto registers.

For most crypto processors the encryption/decryption is either block
by block or DMA mode. In DMA mode you set the key in a register,
the type of encryption in another register and then you set the source
the destination and the length. You then initiate a DMA transfer which
will decrypt your memory area on the fly. In block by block mode you
will have to load every block in a register, set a "go" bit and then
read the decrypted result from another register.

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