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Add OldRandomPool for pre-Crypto++ 5.5 compatibility #452

noloader opened this Issue Aug 1, 2017 · 1 comment


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noloader commented Aug 1, 2017

We are still seeing users stuck at Crypto++ 4.2, Crypto++ 5.2, and other down level versions. The sticking point appears to be the old PGP style RandomPool generator. The PGP style RandomPool is effectively a deterministic generator and it was used as a deterministic key derivation function. See, for example:

While we discourage the old PGP style RandomPool generator for several technical reasons, we should not allow it to be a barrier to a modern Crypto++ upgrade. The lack of a clear migration path and non-interoperability is a security engineering failure on our part.

This issue will track the addition of OldRandomPool to give users a clear and interoperable upgrade path.

@noloader noloader added the Enhancement label Aug 1, 2017

@noloader noloader closed this Aug 1, 2017

noloader referenced this issue Aug 1, 2017

Add OldRandomPool class (Issue 452)
RandomPool used to be a PGP-style deterministic generator and folks used it as a key generation function. At Crypto++ 5.5 the design changed to harden it agianst rollback attacks. The design change resulted in an upgrade barrier. That is, some folks are stuck at Crypto++ 4.2 or Crypto++ 5.2 because they must interoperate with existing software.

Below is the test program we used for the test vector. It was run against Crypto++ 5.4.

    RandomPool prng;
    SecByteBlock seed(0x00, 384), result(64);
    prng.Put(seed, seed.size());

    prng.GenerateBlock(result, result.size());
    HexEncoder encoder(new FileSink(std::cout));

    std::cout << "RandomPool: ";
    encoder.Put(result, sizeof(result));
    std::cout << std::endl;

noloader referenced this issue Aug 1, 2017

Add self tests for OldRandomPool
We still need to get the test result cross-validated

noloader referenced this issue Aug 2, 2017

noloader referenced this issue Aug 2, 2017

noloader referenced this issue Aug 2, 2017

Cut-in RandomNumberGenerator interface to OldRandPool
The existing interface still exists. The new interface is routed into the old methods. Without the new interface, using OldRandPool could result in:
    $ ./cryptest.exe v
    terminate called after throwing an instance of CryptoPP::NotImplemented
      what():  RandomNumberGenerator: IncorporateEntropy not implemented
    Aborted (core dumped)

noloader referenced this issue Aug 3, 2017

Remove pre-Crypto++ 5.5 interface
Users of OldRandomPool must use the new interface. All that means is they must call IncorporateEntropy instead of Put, and GenerateBlock instead of Get

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noloader commented Aug 3, 2017

Cleared at Commit 02e3a794443ae6d9 (addition of OldRandomPool) and Commit 5fbbc5311ceafeba (self tests). Two commits were used in case the self tests need to be updated.

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