Randomizer: always use CSPRNG from OpenSSL #54
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I was too stupid to get |
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The Randomizer class provided an insecure mersenne twister PRNG as a convenience method to draw things like PINs and serial numbers from it. I changed this to always use a secure OpenSSL-based CSPRNG. Furthermore, the OpenSSL PRNG was insecurely seeded from the mersenne twister RNG. Fix this, by combining several input sources via a cryptographic hash function and seed OpenSSL from it. The code now tries to read 256 Bit from different sources and combines them, with SHA-512. When OpenSSL aims for 256 Bit security strength, seed it with at least 1.5x this security strength. Please note, that OpenSSL in typical configurations is automatically seeded and the seeding strategy here probably did no harm by accident in the past. Signed-off-by: Markus Theil <[email protected]>
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Thanks for your pull request. We will look into this soon and cooperate with the BSI. The OpenSSL randomizer is always seeded by OpenSSL itself. RAND_seed won't "reset" the entropy. It will add more entropy like RAND_add. |
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The Randomizer class provided an insecure mersenne twister PRNG as a convenience method to draw things like PINs and serial numbers from it.
I changed this to always use a secure OpenSSL-based CSPRNG.
Furthermore, the OpenSSL PRNG was insecurely seeded from the mersenne twister RNG. Fix this, by combining several input sources via a cryptographic hash function and seed OpenSSL from it.
Please note, that OpenSSL in typical configurations is automatically seeded and the seeding strategy here probably did no harm by accident in the past.