Error message
- Deprecated function: TYPO3\PharStreamWrapper\Manager::initialize(): Implicitly marking parameter $resolver as nullable is deprecated, the explicit nullable type must be used instead in include_once() (line 19 of includes/file.phar.inc).
- Deprecated function: TYPO3\PharStreamWrapper\Manager::initialize(): Implicitly marking parameter $collection as nullable is deprecated, the explicit nullable type must be used instead in include_once() (line 19 of includes/file.phar.inc).
- Deprecated function: TYPO3\PharStreamWrapper\Manager::__construct(): Implicitly marking parameter $resolver as nullable is deprecated, the explicit nullable type must be used instead in include_once() (line 19 of includes/file.phar.inc).
- Deprecated function: TYPO3\PharStreamWrapper\Manager::__construct(): Implicitly marking parameter $collection as nullable is deprecated, the explicit nullable type must be used instead in include_once() (line 19 of includes/file.phar.inc).
- Deprecated function: UpdateQuery::expression(): Implicitly marking parameter $arguments as nullable is deprecated, the explicit nullable type must be used instead in require_once() (line 1884 of includes/database/database.inc).
- Deprecated function: MergeQuery::expression(): Implicitly marking parameter $arguments as nullable is deprecated, the explicit nullable type must be used instead in require_once() (line 1884 of includes/database/database.inc).
- Deprecated function: SelectQueryInterface::getArguments(): Implicitly marking parameter $queryPlaceholder as nullable is deprecated, the explicit nullable type must be used instead in require_once() (line 1884 of includes/database/database.inc).
- Deprecated function: SelectQueryInterface::preExecute(): Implicitly marking parameter $query as nullable is deprecated, the explicit nullable type must be used instead in require_once() (line 1884 of includes/database/database.inc).
- Deprecated function: SelectQueryExtender::getArguments(): Implicitly marking parameter $queryPlaceholder as nullable is deprecated, the explicit nullable type must be used instead in require_once() (line 1884 of includes/database/database.inc).
- Deprecated function: SelectQueryExtender::preExecute(): Implicitly marking parameter $query as nullable is deprecated, the explicit nullable type must be used instead in require_once() (line 1884 of includes/database/database.inc).
- Deprecated function: SelectQuery::getArguments(): Implicitly marking parameter $queryPlaceholder as nullable is deprecated, the explicit nullable type must be used instead in require_once() (line 1884 of includes/database/database.inc).
- Deprecated function: SelectQuery::preExecute(): Implicitly marking parameter $query as nullable is deprecated, the explicit nullable type must be used instead in require_once() (line 1884 of includes/database/database.inc).
Bit commitment is a protocol between two mistrusting
parties, Alice and Bob, which is supposed to provide
the following functionality: In a commit phase, Alice gives as
input a value X (e.g., a bit) and Bob gets a confirmation that Alice has
commited to a value (without learning the actual value of X). Later, in
an opening phase, Alice can decide to reveal the value X to
Bob.
The functionality of a bit commitment protocol can be compared with
that of a safe as follows: To commit to a value X, Alice writes X on a
sheet of paper, locks the paper in the safe, and sends the safe to Bob
while keeping the key. To open the commitment, Alice simply sends the
key to Bob who opens the safe and reads the value of X.
Bit commitment is an important cryptographic primitive as it can be
used as a building block for other tasks such as secure coin
flipping.
Bit commitment can be realized classically in an computationally
secure sense. More precisely, the protocols are either computationally
hiding (in which case it is only computationally secure from Alice's
point of view) or computationally binding (computationally secure from
Bob's point of view). Moreover, it is not hard to prove that
information-theoretically secure bit commitment protocols cannot exist
classically. Interestingly, it could be shown that the same is true if
we allow Alice and Bob to use quantum mechanics.
Bit commitment can be realized generically if one has access to an
oblivious
transfer (OT) primitive. Note that, for that reason, the
impossiblity proofs mentioned above immediately carry over to OT.
Category:Quantum
Cryptography
Last modified:
Monday, October 26, 2015 - 17:56
