A pseudonym is meant to be used as a unique identifier. It can be considered as a public key where the creator of the
pseudonym has the secret key, and it can prove the knowledge of this secret key. This is useful when verifier wants
to attach a unique identifier to a prover without either learning anything unintended (by prover) nor can that unique
identifier be used by other verifiers to identify the prover, eg. a seller (as a verifier) should be able to identify
repeat customers (prover) by using a unique identifier, but verifier should not be able to share that unique identifier
with other sellers using their own identifier for that prover. This is done by making the prover go through a one-time
registration process with the verifier where the prover creates a pseudonym and shares the pseudonym with the verifier.
The prover on subsequent interactions share the pseudonym and proof of knowledge of the pseudonym's secret key with the verifier.
Thus, pseudonyms allow for verifier-local and opt-in linkability.
This concept was introduced in Attribute-based Credentials for Trust, ref. https://link.springer.com/book/10.1007/978-3-319-14439-9.
This implementation of pseudonym uses a non-hiding Pedersen commitment
A pseudonym is meant to be used as a unique identifier. It can be considered as a public key where the creator of the pseudonym has the secret key, and it can prove the knowledge of this secret key. This is useful when verifier wants to attach a unique identifier to a prover without either learning anything unintended (by prover) nor can that unique identifier be used by other verifiers to identify the prover, eg. a seller (as a verifier) should be able to identify repeat customers (prover) by using a unique identifier, but verifier should not be able to share that unique identifier with other sellers using their own identifier for that prover. This is done by making the prover go through a one-time registration process with the verifier where the prover creates a pseudonym and shares the pseudonym with the verifier. The prover on subsequent interactions share the pseudonym and proof of knowledge of the pseudonym's secret key with the verifier. Thus, pseudonyms allow for verifier-local and opt-in linkability. This concept was introduced in Attribute-based Credentials for Trust, ref. https://link.springer.com/book/10.1007/978-3-319-14439-9. This implementation of pseudonym uses a non-hiding Pedersen commitment