 # Firo (formerly Zcoin) Explorer - Reading Assignment

Zcoin still uses ‘mint’ and ‘spend’ transactions, but this time via a new protocol. Use these two links to answer the questions and post your answers below:

1. What is the net number of shielded Zcoins in circulation, as of today?
2. Suppose you want to shield 11.25 Zcoins via Sigmamint. Ignoring change and fee, what will be the number and value of transaction outputs?
3. Alice shields 100 Zcoins via Sigmamint and sends them to Bob via Sigmaspend. What information is visible if you know Alice’s address? If you know Bob’s address?
4. In the above scenario, how do we calculate Bob’s anonymity set? (the number of different plausible senders)
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1. It should be the difference between the amount of ZCoin received (372018.05) and the amount spent (357185.99990202), therefore approximately 14832.05 ZCoin.
2. Ignoring change and fees I think it would create a total of 5 transactions (10 ZCoins + 1 ZCoin + 2*0.1 Zcoins + 0.05 ZCoins).
3. On Alice’s account you would be able to see the amount received and spent as well as the final balance and the total number of transactions. The same goes for Bob’s account. So, the total number of transactions would increase by 1 (with a value of 100 ZCoins) and there would be a decrease in Alice’s balance and an increase in Bob’s.
4. You would be able to find it by checking on https://explorer.zcoin.io/sigmastatus in the “Spent” column because since Bob has received the amount then all other receivers with the same amount would be potential receptors of such transaction.
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1. What is the net number of shielded Zcoins in circulation, as of today?

Total Received 372196.15 - Total Spend 357577.59934187 = 14618.55065813 Total Remaining Unspent

1. Suppose you want to shield 11.26 Zcoins via Sigmamint. Ignoring change and fee, what will be the number and value of transaction outputs?

Sigmamint 11 ZCOIN
0.26 ZCOIN

1. Alice shields 100 Zcoins via Sigmamint and sends them to Bob via Sigmaspend. What information is visible if you know Alice’s address? If you know Bob’s address?

Alice’s spend amount, Bob’s total receive amount, amount of confirmations, Total amount of transaction and Fee amount

1. In the above scenario, how do we calculate Bob’s anonymity set? (the number of different plausible senders)
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In #2 check denominations - 1, .25, .1, etc @bitbooz

#4 it’s all the Sigmamint’s that we know or suspect are unspent.

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1. Shielded Zcoins in circulation, as of today is: 15456

2.I have to guess here 2 and 11 ZCOIN , 0.26 ZCOIN

3.The amount received and spent as well as the final balance and the total number of transaction its the same with Bob.

1. You can find it here https://explorer.zcoin.io/sigmastatus in the spent column
1. 15670,2
2. 4 Sigmamint → 10 ZCOIN , 1 ZCOIN, 0.25 ZCOIN, 0.01 ZCOIN
3. Alice/Bob → The amount received and spent as well as the final balance and the total number of transactions.
4. Look → https://explorer.zcoin.io/sigmastatus
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1. Difference between total received amount of Zcoin and the spent amount: 15471
2. Not quite sure, but I would say: 5: 10, 1, 20, 5 and 1
3. Amount sent, amount received, fee, number of transactions
4. Here: https://explorer.zcoin.io/sigmastatus
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1. What is the net number of shielded Zcoins in circulation, as of today?
376061.15 ZCOIN

2. Suppose you want to shield 11.26 Zcoins via Sigmamint. Ignoring change and fee, what will be the number and value of transaction outputs?
four: 10 + 1 + 0.25 + 0.01

3. Alice shields 100 Zcoins via Sigmamint and sends them to Bob via Sigmaspend. What information is visible if you know Alice’s address? If you know Bob’s address?
Amount sent from Alice, amount sent to Bob, number of transactions, fees

4. In the above scenario, how do we calculate Bob’s anonymity set? (the number of different plausible senders)
all users who have sent a transaction to Sigmamint with the corresponding denominations before

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1. What is the net number of shielded Zcoins in circulation, as of today?
Sigmamint (376193.15 ZCOIN) - Sigmaspend (360690.88098071 ZCOIN) = 15502.27 ZCOIN

2. Suppose you want to shield 11.26 Zcoins via Sigmamint. Ignoring change and fee, what will be the number and value of transaction outputs?
1 output: Sigmamint 11.26 ZCOIN (U), that will create four Zerocoins: 1x10, 1x1, 1x0.25 and 1x0.01.

3. Alice shields 100 Zcoins via Sigmamint and sends them to Bob via Sigmaspend. What information is visible if you know Alice’s address? If you know Bob’s address?
Alice´s sended ammount.
Fees and confirmations in both cases.

4. In the above scenario, how do we calculate Bob’s anonymity set? (the number of different plausible senders)
Column “available” in https://explorer.zcoin.io/sigmastatus.

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1. 376’343.6 – 360’758.38 = 15’585.22 shielded Zcoins in circulation.
2. There should be 4 sigmamints: 10 ZCOIN , 1 ZCOIN, 0.25 ZCOIN, 0.01 ZCOIN
3. With Bob address, I will see the amount received and spent as well as the final balance and the total number of transactions.
4. Here: https://explorer.zcoin.io/sigmastatus
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1. What is the net number of shielded Zcoins in circulation, as of today?

• 377057.9 ZCOIN have been minted in the entire history
• 361085.98021391 ZCOIN have been spent in the entire history
• 377057.9-361085.98021391=15971.91978609 unspent minted coins that are therefore shielded in existence.
2. Suppose you want to shield 11.26 Zcoins via Sigmamint. Ignoring change and fee, what will be the number and value of transaction outputs?

3. Alice shields 100 Zcoins via Sigmamint and sends them to Bob via Sigmaspend. What information is visible if you know Alice’s address? If you know Bob’s address?

• Alice: the amount of zcoins minted
4. In the above scenario, how do we calculate Bob’s anonymity set? (the number of different plausible senders)

• the anonymity set is the minumum available shielded coins per used denomination. So in above scenario, with availability at time of writing of:
Denom Mint Spent Available
100 3,282 3,184 98
25 1,258 1,105 153
10 1,052 928 124
1 6,235 5,260 975
0.5 829 695 134
0.1 2,014 1,587 427
0.05 740 552 188
• 10 has the lowest available of 124 shielded coins -1 = the anonimity set.
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1. The net number of shielded Zcoins is about 16252.77034712 ZCOIN’s = 378458.1Sigmamint - 362205.32965288Sigmaspend
2. To send about 11.26 = Alice needs to use outputs available in denominations{10 + 1 + 0.1 + 0.1 + 0.05} so response is 5 sigmamint_outputs +fee+change
3. from AliceAddress we would see send 100.001 ZCOIN into 1output of 100sigmamint +fee+AliceChange
from BobAddress we would see 1input receiving 100sigmaspend into UnpendOutput(utxo) 99.999 ZCOIN +fee
4. at current timeinstant utc202004301700 and looking at sigmastatus the current amount of the 100 ZCOIN denomination sigmamints that were already changed into sigmaspend are about 3194 total, in one of these addresses we supposedly would find Bob’s address, so I guess Bob’s anonymity set is this scenario is 3193.
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Your intuition is right, but remember ‘RingCT’ is a Monero-ecosystem thing. In the Zero-ecosystem, they are mixed in the ‘Accumulator’ remember.

If it were RingCT, the anonymity set would be the size of the ring (for the limited amount of information you can get from a Monero tx).

For Zero-style accumulators, the anonymity set is the number of plausible decoys in the accumulator.

We’ll read more about this in the ‘Zcoin Comparison’ lesson 1 Like
What is the net number of shielded Zcoins in circulation, as of today?

Net difference: 14,785.02909777

Suppose you want to shield 11.26 Zcoins via Sigmamint. Ignoring change and fee, what will be the number and value of transaction outputs?

10 + 1 + 2*0.1 + 0.05
So 5 transactions.

Alice shields 100 Zcoins via Sigmamint and sends them to Bob via Sigmaspend. What information is visible if you know Alice’s address? If you know Bob’s address?
• Alice: the minted amount
• Bob: the spent amount
In the above scenario, how do we calculate Bob’s anonymity set? (the number of different plausible senders)

This would vary depending on the number of unspent sigma mints in the 100 ZCOIN denomination.

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1 difference between total spent and total recieved , Total Received 372196.15 - Total Spend 357577.59934187 = 14618.55065813 Total Remaining Unspent
2.Sigmamint 11 ZCOIN
0.26 ZCOIN
3.amount sent, amount recieved, fee , number of transactions
4. here https://explorer.zcoin.io/sigmastatus

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1. received 380525 - spent 368695.86835783, so 11829.13164217 remaining
2. 10, 1, .10, .10, .05, and… .01?
3. Alice’s spend amount, Bob’s receive amount, fees.
4. The total number of available coins in each denomination.
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• What is the net number of shielded Zcoins in circulation, as of today?

11944.59

• Suppose you want to shield 11.26 Zcoins via Sigmamint. Ignoring change and fee, what will be the number and value of transaction outputs?

4tx: 10 + 1 + 0.25 + 0.01

• Alice shields 100 Zcoins via Sigmamint and sends them to Bob via Sigmaspend. What information is visible if you know Alice’s address? If you know Bob’s address?

amounts spent/received, amount of Tx, Fees

• In the above scenario, how do we calculate Bob’s anonymity set? (the number of different plausible senders)

is the number of all unspent mints.

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• What is the net number of shielded Zcoins in circulation, as of today?
Total Received 380743 - Total Spend 368764.8312628 = 11978.169

• Suppose you want to shield 11.26 Zcoins via Sigmamint. Ignoring change and fee, what will be the number and value of transaction outputs?
10,1,0.25,0.01

• Alice shields 100 Zcoins via Sigmamint and sends them to Bob via Sigmaspend. What information is visible if you know Alice’s address? If you know Bob’s address?
amount sent, amount received, fee , number of transactions.

• In the above scenario, how do we calculate Bob’s anonymity set? (the number of different plausible senders)
The number of unspent sigma mints in the 100 ZCOIN denomination.

1. What is the net number of shielded Zcoins in circulation, as of today?
The net number of shielded Zcoins in circulation today are (380773.4 - 368964.9812628) 11,808.41873720003 Zcoins.

2. Suppose you want to shield 11.26 Zcoins via Sigmamint. Ignoring change and fee, what will be the number and value of transaction outputs?
This transaction will include 4 outputs which are 10 Zcoin + 1 Zcoin + .25 Zcoin + .01 Zcoin.

3. Alice shields 100 Zcoins via Sigmamint and sends them to Bob via Sigmaspend. What information is visible if you know Alice’s address? If you know Bob’s address?
If Alice’s address is known, you can see funds sent and fees. If Bob’s address is known, you can see funds received and fees.

4. In the above scenario, how do we calculate Bob’s anonymity set? (the number of different plausible senders)
We would have to check sigmastatus. Assuming Bob received one 100 Zcoin mint, as of now his anonymity set would be 71 - 1. If he received 99 (after fees and rounded down for simplicity), I’m guessing this is how you calculate it:

Denom Mint Spent Available
100 3,309 3,239 70
25 1,281 1,180 101
10 1,082 966 116
1 6,358 5,375 983
0.5 850 706 144
0.1 2,074 1,620 454
0.05 760 574 186

(3x 25’s) 101 / 3 = 33.66
(2x 10’s) 116 / 2= 58
(4x 1’s) 983 / 4 = 245.75

^for a total anonymity set of 337.41

@Grant_Hawkins or anyone, is this accurate?

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@andrewfleming Almost! , except subtract at the end rather than divide. So:

101-3 = 98 …

And we don’t combine them, he just has a different anonymity set for each tx.

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