Instead of a single struct TALER_AgeCommitment, we now use
1. TALER_AgeCommitment for the age mask and list public keys for age
restriciton.
2. TALER_AgeProof for list of private keys for age restriction
3. TALER_AgeCommitmentProof for the aggregation of the former two.
Also, we introduce TALER_AgeAttestation as the EDDSA signature to attest
a particular age group, along with the function prototypes
TALER_age_commitment_attest and TALER_age_commitment_verify.
Age restriction works now with withdraw, melt/refresh/reveal and link,
including tests.
However, there is still a problem with the tests: The melting operation
"refresh-melt-failing-age" that should fail (because of conflict), but
currently fails for other reasons. I decided to disable that particular
test (and the next) and submit the patch I have so far.
Added age restriction support for
- melt/refresh/reveal
- recoup
However, tests are not yet implemented for those flows.
Also: minor fixes and refactoring.
Age restriction support for
- withdraw is done and tested
- deposit is done and tested
TODOs:
- melt/refresh/reveal
- link
------
Added functions
- TALER_age_restriction_commit
- TALER_age_commitment_derive
- TALER_age_commitment_hash
- TALER_age_restriction_commitment_free_inside
- Hash of age commitment passed around API boundaries
Exchangedb adjustments for denominations
- all prepared statements re: denominations now handle age_mask
- signature parameters adjusted
Hash and signature verification of /keys adjusted
- Hashes of (normal) denominations and age-restricted denominations are
calculated seperately
- The hash of the age-restricted ones will then be added to the other
hash
- The total hash is signed/verified
Tests for withdraw with age restriction added
- TALER_EXCHANGE_DenomPublickey now carries age_mask
- TALER_TESTING_cmd_withdraw_amount* takes age parameter
- TALER_TESTING_find_pk takes boolean age_restricted
- WithdrawState carries age_commitment and its hash
- withdraw_run derives new age commitment, if applicable
- Added age parameter to testing (13 as example)
Various Fixes and changes
- Fixes of post handler for /management/extensions
- Fixes for offline tool extensions signing
- Slight refactoring of extensions
- Age restriction extension simplified
- config is now global to extension
- added global TEH_age_restriction_enabled and TEH_age_mask in
taler-exchange-httpd
- helper functions and macros introduced
The current "/recoup" API does not have clear idempotency semantics, as we've discussed on the phone. This is already bad by itself, as it makes it hard to write down what the API does other than "whatever the implementation does".
However, it actually breaks correctness in this (admittedly kinda contrived, but not impossible) case:
Say that we have a coin A obtained via withdrawal and a coin B obtained via refreshing coin A. Now the denominations of A gets revoked..
The wallet does a recoup of A for EUR:1.
Now the denomination of B also gets revoked. The wallet recoups B (incidentally also for EUR:1) and now A can be recouped again for EUR:1. But now the exchange is in a state where it will refuse a legitimate recoup request for A because the detection for an idempotent request kicks in.
This is IMHO bad API design, and the exchange should simply always recoup the maximum amount.
Furthermore, we usually follow the principle of "API calls that take up DB space are paid". With the current recoup API, I can do many tiny recoup requests which the exchange then has to store, right?
I guess it would not be a big change to remove the "amount" value from the recoup/recoup-refresh request bodies, right?
- Florian
