Direct read from /dev/urandom without PRNG?

[Sudha Duraiswamy]

Hi David,

Is it possible to not use PRNG from Bouncy Castle and directly read from /dev/urandom in FIPS mode? Please assume that the system has a good entropy source and has a CMVP certification.

In other words, is it possible to use the PRNG/DRNG of the kernel in Bouncy Castle?

Please let me know!

Thanks,

Sudha

[David Hook-3]

Anything's possible (well almost...) If the source for /dev/urandom is
compliant I think you'd just need to configure:

securerandom.strongAlgorithms=NativePRNGNonBlocking:SUN

this will mean that any DRBG created by the FIPS module will use
/dev/urandom for seeding.

Regards,

David

On 23/2/21 8:52 am, Sudha Duraiswamy wrote:

> Hi David,
>
> Is it possible to not use PRNG from Bouncy Castle and directly read
> from /dev/urandom in FIPS mode? Please assume that the system has a
> good entropy source and has a CMVP certification.
>
> In other words, is it possible to use the PRNG/DRNG of the kernel in
> Bouncy Castle?
>
> Please let me know!
>
> Thanks,
> Sudha

[Sudha Duraiswamy]

Hi David,

Thank you for the info! 

To be more specific, would it be possible to not use the DRBG of the FIPS module at all? I see that BC has received CAVP certification (C467)  and conforms to SP-800 90A, which means BC has it's own DRNG.

        https://csrc.nist.gov/projects/cryptographic-algorithm-validation-program/Details?validation=30863

Is there a way to tune BC to read from /dev/urandom for random data without going through DRBG of BC?

Regards,

Sudha

On Mon, Feb 22, 2021 at 3:26 PM David Hook <[hidden email]> wrote:

Anything's possible (well almost...) If the source for /dev/urandom is
compliant I think you'd just need to configure:

securerandom.strongAlgorithms=NativePRNGNonBlocking:SUN

this will mean that any DRBG created by the FIPS module will use
/dev/urandom for seeding.

Regards,

David

On 23/2/21 8:52 am, Sudha Duraiswamy wrote:
> Hi David,
>
> Is it possible to not use PRNG from Bouncy Castle and directly read
> from /dev/urandom in FIPS mode? Please assume that the system has a
> good entropy source and has a CMVP certification.
>
> In other words, is it possible to use the PRNG/DRNG of the kernel in
> Bouncy Castle?
>
> Please let me know!
>
> Thanks,
> Sudha

[David Hook-3]

Hi Sudha,

BC implements DRBG algorithms, not RNGs - it is a FIPS requirement to use a certified DRBG for key generation (and GCM IVs if you are doing it dynamically). The default DRBG for the FIPS provider will use prediction resistant mode though - meaning it will reseed on every invocation. "prediction resistant" mode is probably what you are looking for, this will read from /dev/urandom (in your case) each time a key is generated, but ensure that the original seed material (from /dev/urandom) is never directly used or exposed.

Regards,

David

On 23/2/21 11:21 am, Sudha Duraiswamy wrote:

Hi David,

Thank you for the info! 

To be more specific, would it be possible to not use the DRBG of the FIPS module at all? I see that BC has received CAVP certification (C467)  and conforms to SP-800 90A, which means BC has it's own DRNG.

        https://csrc.nist.gov/projects/cryptographic-algorithm-validation-program/Details?validation=30863

Is there a way to tune BC to read from /dev/urandom for random data without going through DRBG of BC?

Regards,

Sudha

On Mon, Feb 22, 2021 at 3:26 PM David Hook <[hidden email]> wrote:

Anything's possible (well almost...) If the source for /dev/urandom is
compliant I think you'd just need to configure:

securerandom.strongAlgorithms=NativePRNGNonBlocking:SUN

this will mean that any DRBG created by the FIPS module will use
/dev/urandom for seeding.

Regards,

David

On 23/2/21 8:52 am, Sudha Duraiswamy wrote:
> Hi David,
>
> Is it possible to not use PRNG from Bouncy Castle and directly read
> from /dev/urandom in FIPS mode? Please assume that the system has a
> good entropy source and has a CMVP certification.
>
> In other words, is it possible to use the PRNG/DRNG of the kernel in
> Bouncy Castle?
>
> Please let me know!
>
> Thanks,
> Sudha