I think, I got the answer

http://www.cisco.com/en/US/products/sw/iosswrel/ps1829/products_feature_guide09186a0080088197.html


IPS Sensor supports only ssh version 1. The SSH version 1 has the
exponent/modulus form. With putty, when you try to generate a key with ssh 1
selected,
you will see the exponent/modulus form.


But there is one thing, for which I don't have the answer.

If the router is enabled with SSH 1.5 and then I try to retrieve key with
the "ssh host-key" command, the public key is retrieved in exponent/modulus
form.

My question is, whether the sensor retrieved ssh 2 key and converted it from
ssh 2 ASN standard form to exponent/modulus form or did the sesnor, retrieve
a ssh 1 key from the router?

Please let me know, if I understanding is wrong.


Sample key forms - Putty generated - SSH 1 (RSA)

Length is 1024 bits and modulus is 37

1024 
371158752216491277321143480861548661325873614263583576212066973466808497469254739660437295
19506303480757940517966837316689423718091873046190440464148525456076201624869460019390136017038
629566585251171321652233698473919255794937271507497859475290155713291539954226873359290672693498
530564975571658800697844069461


Sample key forms - Putty generated - SSH 2 (RSA)

AAAAB3NzaC1yc2EAAAABJQAAAIEAgZNH+Xq6/HNcopKkNDXUbD4TSJz7hS/I++mYcj+guwigw9fPL+n5aDHCJJv3X
RJYeVd4ZCcT0t8SND4bDtLUSrz1vvgw9Ep4YbI7niL0SeWAQKiZsVZZm+0t7xfybFYBdmkUaLq8pd0vU+0Pcxf/wXjsDN
vh6i/RHHiQmvkvK


With regards
Kings


On Wed, Jul 29, 2009 at 11:13 AM, Kingsley Charles <
[email protected]> wrote:

> Hello everyone
>
> On the IPS sensor, if you need to add a router to the ssh known host list,
> we need to add the router's RSA public key in the sensor.
>
> We have two options:
>
> Automatically, we can make the Sensor to retrieve the key from the router
> using "ssh host-key" command.
>
> Manually add the key going to "service ssh-known-host".
>
> For the second option, the sensor expects the key in "exponent/modulus"
> format.
>
> But the problem is, if you issue "show crypto key mypubkey rsa" on the
> router, the key is displayed in the standard ASN Hex format.
>
>
>
> *Please let me know a tool that can convert the "standard RSA Hex format"
> key into "Exponent/modulus decimal form", so that I can add it to the
> Sensor.*
>
> I tried to putty and there is no option in that.
>
>
>
>
>
> With regards
> Kings
>
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