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Module primitives

Module primitives 

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PEP primitives for rekeying, reshuffleing, rerandomizeation of ElGamal ciphertexts, their transitive and reversible n-PEP extensions, and combined versions.

Functionsยง

rekey
Make a message encrypted under one key decryptable under another key. If the original message was encrypted under key Y, the new message will be encrypted under key k * Y such that users with secret key k * y can decrypt it.
rekey2
A transitive and reversible n-PEP extension of rekey, rekeying from one key to another.
rerandomize
Change the representation of a ciphertext without changing the contents. Used to make multiple unlinkable copies of the same ciphertext (when disclosing a single stored message multiple times).
reshuffle
Change the contents of a ciphertext with factor s, i.e. message M becomes s * M. Can be used to blindly and pseudo-randomly pseudonymize identifiers.
reshuffle2
A transitive and reversible n-PEP extension of reshuffle, reshuffling from one pseudonym to another.
rrsk
Combination of rerandomize, reshuffle and rekey (more efficient and secure than applying them separately).
rrsk2
A transitive and reversible n-PEP extension of rrsk.
rsk
Combination of reshuffle and rekey (more efficient and secure than applying them separately).
rsk2
A transitive and reversible n-PEP extension of rsk.