The below situation is for the case where a given credential issuer must generate credentials for multiple attributes. I have a doubt that needs clarification, an is important for IoT case:

Credentials from same credential issuer but for different attributes

At step 3, I understand that the credential issuer must issue a pair of keys per attribute to be validated with a credential. Because the public key of the credential issuer is used to validate the credential linked to the specific attribute.

So, if the credential issuer service wishes to be able to issue credentials for different attributes, it must:

• Generate one key pair per attribute needed to be verifierd
• Keep track of each attribute - public/private key pair via the parametter "ci_unique_id".
• Be able to distribute those public keys to anyone wishing to verify the credential (step 8).

Otherwise, I do not understand how the checker can validate the credential, without any more info other than the public key of the credential issuer. Somehow there must be alink between the attribute that is valid for the credential, and the credential? (I'm refering to step 8, "ci_unique_id")

please clarify :)

When passing contract 13 a petition with 0 signatures, the count contract (14) fails to produce output, this is the log of Zenroom:

[] Zenroom v0.8.1 - crypto language restricted VM
. Copyright (C) 2017-2019 Dyne.org foundation
. reading KEYS from file: credential.json
. loaded file (865 bytes)
. reading DATA from file: petition.json
. loaded file (1424 bytes)
[] reading Zencode from file: ./src/13-CITIZEN-tally-petition.zencode
. loaded file (390 bytes)
. using default configuration
. loading lua initialisation
[] Direct Zencode execution
. starting execution.
[] Execution completed.
. Zenroom teardown.
[] Zenroom v0.8.1 - crypto language restricted VM
. Copyright (C) 2017-2019 Dyne.org foundation
. reading KEYS from file: tally.json
. loaded file (1151 bytes)
. reading DATA from file: petition.json
. loaded file (1424 bytes)
[] reading Zencode from file: ./src/14-CITIZEN-count-petition.zencode
. loaded file (226 bytes)
. using default configuration
. loading lua initialisation
[*] Direct Zencode execution
. starting execution.
[!] ECP point validation returns -2
[!] [string "zencode_schemas"]:26: Octet is not a valid public key (point is not on this curve)
. Zenroom teardown.