random doctest failure in src/sage/tests/book_stein_ent.py

[yyyyx4]

Part of #32544:

sage -t --long --random-seed=248665222928234939040854301866666446071 src/sage/tests/book_stein_ent.py
**********************************************************************
File "src/sage/tests/book_stein_ent.py", line 208, in sage.tests.book_stein_ent
Failed example:
    decrypt(c, d, n)
Expected:
    123
Got:
    109489
**********************************************************************
1 item had failures:
   1 of 262 in sage.tests.book_stein_ent
    [261 tests, 1 failure, 15.47 s]

(From a patchbot run in #32744.)

CC: @williamstein

Component: cryptography

Author: Michael Orlitzky

Branch/Commit: 7bb8387

Reviewer: Lorenz Panny

Issue created by migration from https://trac.sagemath.org/ticket/33035

[yyyyx4]

comment:1

The error is because the preceding call to rsa() generates a key with p=q when using this seed.

[orlitzky]

comment:3

Instead of

....:     p = next_prime(ZZ.random_element(2**(bits//2 +1)),
....:                    proof=proof)
....:     q = next_prime(ZZ.random_element(2**(bits//2 +1)),
....:                    proof=proof)

we should be able to do

....:     p = q = ZZ.zero()
....:     while (p == q):
....:         p = next_prime(ZZ.random_element(2**(bits//2 +1)),
....:                        proof=proof)
....:         q = next_prime(ZZ.random_element(2**(bits//2 +1)),
....:                        proof=proof)

(we really only need to regenerate q, but this is nice and symmetric.)

But for these tests to serve their intended purpose we'll need William (hint hint) to pick a solution so that it can be incorporated into the book (https://github.com/williamstein/ent) as well.

[williamstein]

comment:4

Hint taken. How about this?

....:     while True:
....:         p = next_prime(ZZ.random_element(2**(bits//2 + 1)),
....:                        proof=proof)
....:         q = next_prime(ZZ.random_element(2**(bits//2 + 1)),
....:                        proof=proof)
....:         if p != q: break

[orlitzky]

comment:5

Replying to @williamstein:

Hint taken. How about this?

Even better. I'll post a branch later today. Thanks.

[orlitzky]

Last 10 new commits:

26a7332	build/pkgs/singular/spkg-install.in: Remove workaround for singular.idx, it is now in doc.tbz2
bb1f741	build/pkgs/singular/spkg-install.in: Remove workaround for make paralellization bugs
2673632	Port to API changes in singular 4.2.1p2
720d10e	Update tests for singular 4.2.1p2
cca353b	src/sage/rings/polynomial/hilbert.pyx: Fix doctest markup
8c6c949	build/pkgs/flint/: Add patch for threads with GCC < 4.9
eea6328	build/pkgs/singular/spkg-install.in: singular.hlp -> singular.info
a137b7e	Merge tag '9.5.beta8' into t/32907/update_singular_to_4_2_1p2
0856554	build/pkgs/singular: Update to 4.2.1p3
e1c448e	Merge commit '0856554' into develop

[orlitzky]

Commit: e1c448e

[orlitzky]

Branch: u/mjo/ticket/33035

[orlitzky]

Author: Michael Orlitzky

[orlitzky]

comment:7

Those extra commits are from #32907 which is already merged but isn't in beta9.

[sagetrac-git]

Branch pushed to git repo; I updated commit sha1. New commits:

7bb8387

Trac #33035: fix a randomly failing test in sage.tests.book_stein_ent.

[sagetrac-git]

Changed commit from e1c448e to 7bb8387

[yyyyx4]

Reviewer: Lorenz Panny

[slel]

comment:10

Setting milestone to 9.6 now that 9.5 is out.

[vbraun]

Changed branch from u/mjo/ticket/33035 to 7bb8387