# 95-702 Distributed Systems Project 3
### Author Le-Hao, Hsu (Gavin Hsu)
### Andrew Id: lehaoh

## Task 0
### Task 0 Execution

0. View basic blockchain status.
1. Add a transaction to the blockchain.
2. Verify the blockchain.
3. View the blockchain.
4. Corrupt the chain.
5. Hide the corruption by repairing the chain.
6. Exit
0
Current size of chain: 1
Difficulty of most recent block: 2
Total difficulty for all blocks: 2
Approximate hashes per second on this machine: 2375296
Expected total hashes required for the whole chain: 256.0
Nonce for the most recent block: 304
Chain hash: 00E1613831F69101BBBAA51BBB285C98CC55BF96B8035406C080344299BDDEE0

0. View basic blockchain status.
1. Add a transaction to the blockchain.
2. Verify the blockchain.
3. View the blockchain.
4. Corrupt the chain.
5. Hide the corruption by repairing the chain.
6. Exit
1
Enter difficulty > 0
2
Enter transaction
Alice pays Bob 100DSCoin

Total execution time was 6 milliseconds

0. View basic blockchain status.
1. Add a transaction to the blockchain.
2. Verify the blockchain.
3. View the blockchain.
4. Corrupt the chain.
5. Hide the corruption by repairing the chain.
6. Exit
1
Enter difficulty > 0
2
Enter transaction
Bob pays Carol 50DSCoin
Total execution time was 4 milliseconds

0. View basic blockchain status.
1. Add a transaction to the blockchain.
2. Verify the blockchain.
3. View the blockchain.
4. Corrupt the chain.
5. Hide the corruption by repairing the chain.
6. Exit
1
Enter difficulty > 0
2
Enter transaction
Carol pays Donna 10 DSCoin
Total execution time was 2 milliseconds

0. View basic blockchain status.
1. Add a transaction to the blockchain.
2. Verify the blockchain.
3. View the blockchain.
4. Corrupt the chain.
5. Hide the corruption by repairing the chain.
6. Exit
2
Chain Verification: TRUE
Total execution time to verify the chain was 0 milliseconds

0. View basic blockchain status.
1. Add a transaction to the blockchain.
2. Verify the blockchain.
3. View the blockchain.
4. Corrupt the chain.
5. Hide the corruption by repairing the chain.
6. Exit
3
View the Blockchain
{"ds_chain":
"["{"index":0,"time stamp ":"2022-10-28 16:47:24.988",
"Tx ":"Genesis","PrevHash ":"","nonce":304, "difficulty":2}",
"{"index":1,"time stamp ":"2022-10-28 17:03:29.729",
"Tx ":"Alice pays Bob 100DSCoin",
"PrevHash":"00E1613831F69101BBBAA51BBB285C98CC55BF96B8035406C080344299BDDEE0",
"nonce":285,"difficulty":2}",
"{"index":2,"time stamp ":"2022-10-28 17:05:39.994",
"Tx ":"Bob pays Carol 50DSCoin",
"PrevHash":"0067A51584B0CB75BD57E377F58F3FAA4658A6F49F36D1778C7208804AD1D219",
"nonce":145,"difficulty":2}",
"{"index":3,"time stamp ":"2022-10-28 17:06:51.353",
"Tx ":"Carol pays Donna 10 DSCoin",
"PrevHash ":"0064F804A776E4C65C7967B31AF744778F0C771E00A8EABFD634640E1C89290A",
"nonce":63,"difficulty":2}"]",
"chainHash":"000AA45954E697AB25B0EA923300EC87CD052DC6F8A41E2D683C0EAB06C27D1D"}

0. View basic blockchain status.
1. Add a transaction to the blockchain.
2. Verify the blockchain.
3. View the blockchain.
4. Corrupt the chain.
5. Hide the corruption by repairing the chain.
6. Exit
4
corrupt the Blockchain
Enter block ID of block to corrupt
1
Enter new data for block 1
Alice pays Bob 76 DScoin
Block 1 now holds Alice pays Bob 76 DScoin

0. View basic blockchain status.
1. Add a transaction to the blockchain.
2. Verify the blockchain.
3. View the blockchain.
4. Corrupt the chain.
5. Hide the corruption by repairing the chain.
6. Exit
3
View the Blockchain
{"ds_chain":
"["{"index":0,"time stamp ":"2022-10-28 16:47:24.988",
"Tx ":"Genesis","PrevHash ":"","nonce":304,"difficulty":2}",
"{"index":1,"time stamp ":"2022-10-28 17:03:29.729",
"Tx ":"Alice pays Bob 76 DScoin",
"PrevHash ":"00E1613831F69101BBBAA51BBB285C98CC55BF96B8035406C080344299BDDEE0",
"nonce":285,"difficulty":2}",
"{"index":2,"time stamp ":"2022-10-28 17:05:39.994",
"Tx ":"Bob pays Carol 50DSCoin",
"PrevHash ":"0067A51584B0CB75BD57E377F58F3FAA4658A6F49F36D1778C7208804AD1D219",
"nonce":145,"difficulty":2}",
"{"index":3,"time stamp ":"2022-10-28 17:06:51.353",
"Tx ":"Carol pays Donna 10 DSCoin",
"PrevHash ":"0064F804A776E4C65C7967B31AF744778F0C771E00A8EABFD634640E1C89290A",
"nonce":63,"difficulty":2}"]",
"chainHash":"000AA45954E697AB25B0EA923300EC87CD052DC6F8A41E2D683C0EAB06C27D1D"}

0. View basic blockchain status.
1. Add a transaction to the blockchain.
2. Verify the blockchain.
3. View the blockchain.
4. Corrupt the chain.
5. Hide the corruption by repairing the chain.
6. Exit
2
Chain verification: FALSE
Improper hash on node 1 Does not begin with 00
Total execution time to verify the chain was 1 milliseconds

0. View basic blockchain status.
1. Add a transaction to the blockchain.
2. Verify the blockchain.
3. View the blockchain.
4. Corrupt the chain.
5. Hide the corruption by repairing the chain.
6. Exit
5
Total execution time required to repair the chain was 5 milliseconds

0. View basic blockchain status.
1. Add a transaction to the blockchain.
2. Verify the blockchain.
3. View the blockchain.
4. Corrupt the chain.
5. Hide the corruption by repairing the chain.
6. Exit
2
Chain Verification: TRUE
Total execution time to verify the chain was 0 milliseconds

0. View basic blockchain status.
1. Add a transaction to the blockchain.
2. Verify the blockchain.
3. View the blockchain.
4. Corrupt the chain.
5. Hide the corruption by repairing the chain.
6. Exit
1
Enter difficulty > 0
4
Enter transaction
Donna pays Sean 25 DScoin
Total execution time was 169 milliseconds

0. View basic blockchain status.
1. Add a transaction to the blockchain.
2. Verify the blockchain.
3. View the blockchain.
4. Corrupt the chain.
5. Hide the corruption by repairing the chain.
6. Exit
0
Current size of chain: 5
Difficulty of most recent block: 4
Total difficulty for all blocks: 12
Approximate hashes per second on this machine: 2375296
Expected total hashes required for the whole chain: 66560.0
Nonce for the most recent block: 39563
Chain hash: 0000FCDFF92976C2167D4192B1C3E960FE566DF5D9B0FD75B03BAA279ECE3CDC

0. View basic blockchain status.
1. Add a transaction to the blockchain.
2. Verify the blockchain.
3. View the blockchain.
4. Corrupt the chain.
5. Hide the corruption by repairing the chain.
6. Exit
6


Process finished with exit code 0

### Task 0 Block.java





### Task 0 BlockChain.java










### The analysis in the main routine

*Comment is in the below of the code*

1. addBlock()

    0. View basic blockchain status.
    1. Add a transaction to the blockchain.
    2. Verify the blockchain.
    3. View the blockchain.
    4. Corrupt the chain.
    5. Hide the corruption by repairing the chain.
    6. Exit
    1
    Enter difficulty > 0
    2
    Enter transaction
    Difficulty equals 2
    Total execution time was 1 milliseconds

    0. View basic blockchain status.
    1. Add a transaction to the blockchain.
    2. Verify the blockchain.
    3. View the blockchain.
    4. Corrupt the chain.
    5. Hide the corruption by repairing the chain.
    6. Exit
    1
    Enter difficulty > 0
    3
    Enter transaction
    Difficulty equals 3
    Total execution time was 8 milliseconds

    0. View basic blockchain status.
    1. Add a transaction to the blockchain.
    2. Verify the blockchain.
    3. View the blockchain.
    4. Corrupt the chain.
    5. Hide the corruption by repairing the chain.
    6. Exit
    1
    Enter difficulty > 0
    4
    Enter transaction
    Difficulty equals 4
    Total execution time was 29 milliseconds

    0. View basic blockchain status.
    1. Add a transaction to the blockchain.
    2. Verify the blockchain.
    3. View the blockchain.
    4. Corrupt the chain.
    5. Hide the corruption by repairing the chain.
    6. Exit
    1
    Enter difficulty > 0
    5
    Enter transaction
    Difficulty equals 5
    Total execution time was 816 milliseconds

2. isChainValid() & chainRepair()

    0. View basic blockchain status.
    1. Add a transaction to the blockchain.
    2. Verify the blockchain.
    3. View the blockchain.
    4. Corrupt the chain.
    5. Hide the corruption by repairing the chain.
    6. Exit
    2
    Chain Verification: TRUE
    Total execution time to verify the chain was 0 milliseconds

    0. View basic blockchain status.
    1. Add a transaction to the blockchain.
    2. Verify the blockchain.
    3. View the blockchain.
    4. Corrupt the chain.
    5. Hide the corruption by repairing the chain.
    6. Exit
    4
    corrupt the Blockchain
    Enter block ID of block to corrupt
    3
    Enter new data for block 3
    Corrupt block 3
    Block 3 now holds Corrupt block 3

    0. View basic blockchain status.
    1. Add a transaction to the blockchain.
    2. Verify the blockchain.
    3. View the blockchain.
    4. Corrupt the chain.
    5. Hide the corruption by repairing the chain.
    6. Exit
    5
    Total execution time required to repair the chain was 652 milliseconds

    0. View basic blockchain status.
    1. Add a transaction to the blockchain.
    2. Verify the blockchain.
    3. View the blockchain.
    4. Corrupt the chain.
    5. Hide the corruption by repairing the chain.
    6. Exit
    2
    Chain Verification: TRUE
    Total execution time to verify the chain was 0 milliseconds

    0. View basic blockchain status.
    1. Add a transaction to the blockchain.
    2. Verify the blockchain.
    3. View the blockchain.
    4. Corrupt the chain.
    5. Hide the corruption by repairing the chain.
    6. Exit
    4
    corrupt the Blockchain
    Enter block ID of block to corrupt
    4
    Enter new data for block 4
    Corrupt block 4
    Block 4 now holds Corrupt block 4

    0. View basic blockchain status.
    1. Add a transaction to the blockchain.
    2. Verify the blockchain.
    3. View the blockchain.
    4. Corrupt the chain.
    5. Hide the corruption by repairing the chain.
    6. Exit
    2
    Chain verification: FALSE
    Improper hash on node 4 Does not begin with 00000
    Total execution time to verify the chain was 2 milliseconds

    0. View basic blockchain status.
    1. Add a transaction to the blockchain.
    2. Verify the blockchain.
    3. View the blockchain.
    4. Corrupt the chain.
    5. Hide the corruption by repairing the chain.
    6. Exit
    5
    Total execution time required to repair the chain was 1848 milliseconds

    0. View basic blockchain status.
    1. Add a transaction to the blockchain.
    2. Verify the blockchain.
    3. View the blockchain.
    4. Corrupt the chain.
    5. Hide the corruption by repairing the chain.
    6. Exit
    2
    Chain Verification: TRUE
    Total execution time to verify the chain was 0 milliseconds

## Task1
## Task 1 Client Side Execution

The client is running.
Please enter server port: 
6789
0. View basic blockchain status.
1. Add a transaction to the blockchain.
2. Verify the blockchain.
3. View the blockchain.
4. Corrupt the chain.
5. Hide the corruption by repairing the chain.
6. Exit
0
Current size of chain: 1
Difficulty of most recent block: 2
Total difficulty for all blocks: 2
Approximate hashes per second on this machine: 2475247
Expected total hashes required for the whole chain: 256.0
Nonce for the most recent block: 50
Chain hash: 00B3AF7E0A12DF2FE87007728AA78FFEB1478130CFDEAF0DCE8C1E378A58FDC6

0. View basic blockchain status.
1. Add a transaction to the blockchain.
2. Verify the blockchain.
3. View the blockchain.
4. Corrupt the chain.
5. Hide the corruption by repairing the chain.
6. Exit
1
Enter difficulty > 0
2
Enter transaction
Alice pays Bob 100DSCoin
Total execution time was 6 milliseconds

0. View basic blockchain status.
1. Add a transaction to the blockchain.
2. Verify the blockchain.
3. View the blockchain.
4. Corrupt the chain.
5. Hide the corruption by repairing the chain.
6. Exit
1
Enter difficulty > 0
2
Enter transaction
Bob pays Carol 50DSCoin
Total execution time was 3 milliseconds

0. View basic blockchain status.
1. Add a transaction to the blockchain.
2. Verify the blockchain.
3. View the blockchain.
4. Corrupt the chain.
5. Hide the corruption by repairing the chain.
6. Exit
1
Enter difficulty > 0
2
Enter transaction
Carol pays Donna 10 DSCoin
Total execution time was 1 milliseconds

0. View basic blockchain status.
1. Add a transaction to the blockchain.
2. Verify the blockchain.
3. View the blockchain.
4. Corrupt the chain.
5. Hide the corruption by repairing the chain.
6. Exit
2
Chain Verification: TRUE
Total execution time to verify the chain was 0 milliseconds

0. View basic blockchain status.
1. Add a transaction to the blockchain.
2. Verify the blockchain.
3. View the blockchain.
4. Corrupt the chain.
5. Hide the corruption by repairing the chain.
6. Exit
3
View the Blockchain
{"ds_chain":
"["{"index":0,"time stamp ":"2022-10-31 03:09:53.721",
"Tx ":"Genesis","PrevHash ":"","nonce":50,"difficulty":2}",
"{"index":1,"time stamp ":"2022-10-31 03:10:09.158",
"Tx ":"Alice pays Bob 100DSCoin",
"PrevHash ":"00B3AF7E0A12DF2FE87007728AA78FFEB1478130CFDEAF0DCE8C1E378A58FDC6",
"nonce":135,"difficulty":2}",
"{"index":2,"time stamp ":"2022-10-31 03:10:22.94",
"Tx ":"Bob pays Carol 50DSCoin",
"PrevHash ":"00E39555ADA83C280660B575BA5D72F2DBE833292D4EF676AC6C94C9D41EEC06",
"nonce":67,"difficulty":2}",
"{"index":3,"time stamp ":"2022-10-31 03:10:34.685",
"Tx ":"Carol pays Donna 10 DSCoin",
"PrevHash ":"0090B614E9E3C0BEF7C4F493266CBF337DABFED379F9449650A9B12773F69A91",
"nonce":24,"difficulty":2}"]",
"chainHash":"00BB3DB92B60CADC4DD84CC80C82846E449411F359399DA99887E4C55911AFA6"}

0. View basic blockchain status.
1. Add a transaction to the blockchain.
2. Verify the blockchain.
3. View the blockchain.
4. Corrupt the chain.
5. Hide the corruption by repairing the chain.
6. Exit
4
corrupt the Blockchain
Enter block ID of block to corrupt
1
Enter new data for block 1
Alice pays Bob 76 DScoin
Block 1 now holds Alice pays Bob 76 DScoin

0. View basic blockchain status.
1. Add a transaction to the blockchain.
2. Verify the blockchain.
3. View the blockchain.
4. Corrupt the chain.
5. Hide the corruption by repairing the chain.
6. Exit
3
View the Blockchain
{"ds_chain":
"["{"index":0,"time stamp ":"2022-10-31 03:09:53.721",
"Tx ":"Genesis","PrevHash ":"","nonce":50,"difficulty":2}",
"{"index":1,"time stamp ":"2022-10-31 03:10:09.158",
"Tx ":"Alice pays Bob 76 DScoin",
"PrevHash ":"00B3AF7E0A12DF2FE87007728AA78FFEB1478130CFDEAF0DCE8C1E378A58FDC6",
"nonce":135,"difficulty":2}",
"{"index":2,"time stamp ":"2022-10-31 03:10:22.94",
"Tx ":"Bob pays Carol 50DSCoin",
"PrevHash ":"00E39555ADA83C280660B575BA5D72F2DBE833292D4EF676AC6C94C9D41EEC06",
"nonce":67,"difficulty":2}",
"{"index":3,"time stamp ":"2022-10-31 03:10:34.685",
"Tx ":"Carol pays Donna 10 DSCoin",
"PrevHash ":"0090B614E9E3C0BEF7C4F493266CBF337DABFED379F9449650A9B12773F69A91",
"nonce":24,"difficulty":2}"]",
"chainHash":"00BB3DB92B60CADC4DD84CC80C82846E449411F359399DA99887E4C55911AFA6"}

0. View basic blockchain status.
1. Add a transaction to the blockchain.
2. Verify the blockchain.
3. View the blockchain.
4. Corrupt the chain.
5. Hide the corruption by repairing the chain.
6. Exit
2
Chain verification: FALSE
Improper hash on node 1 Does not begin with 00
Total execution time to verify the chain was 1 milliseconds

0. View basic blockchain status.
1. Add a transaction to the blockchain.
2. Verify the blockchain.
3. View the blockchain.
4. Corrupt the chain.
5. Hide the corruption by repairing the chain.
6. Exit
5
Total execution time required to repair the chain was 10 milliseconds

0. View basic blockchain status.
1. Add a transaction to the blockchain.
2. Verify the blockchain.
3. View the blockchain.
4. Corrupt the chain.
5. Hide the corruption by repairing the chain.
6. Exit
2
Chain Verification: TRUE
Total execution time to verify the chain was 0 milliseconds

0. View basic blockchain status.
1. Add a transaction to the blockchain.
2. Verify the blockchain.
3. View the blockchain.
4. Corrupt the chain.
5. Hide the corruption by repairing the chain.
6. Exit
1
Enter difficulty > 0
4
Enter transaction
Donna pays Sean 25 DScoin
Total execution time was 204 milliseconds

0. View basic blockchain status.
1. Add a transaction to the blockchain.
2. Verify the blockchain.
3. View the blockchain.
4. Corrupt the chain.
5. Hide the corruption by repairing the chain.
6. Exit
0
Current size of chain: 5
Difficulty of most recent block: 4
Total difficulty for all blocks: 12
Approximate hashes per second on this machine: 2475247
Expected total hashes required for the whole chain: 66560.0
Nonce for the most recent block: 51812
Chain hash: 0000A3A301A9A280EFB5F793C92EABF756E2ED2085B68C12A55F2369AEA78ADF

0. View basic blockchain status.
1. Add a transaction to the blockchain.
2. Verify the blockchain.
3. View the blockchain.
4. Corrupt the chain.
5. Hide the corruption by repairing the chain.
6. Exit
6
Client side quitting. The remote variable server is still running.

### Task 1 Server Side Execution

Blockchain server running.
We have a visitor
Response: {"selection":1,"size":"1",
"chainHash":"00B3AF7E0A12DF2FE87007728AA78FFEB1478130CFDEAF0DCE8C1E378A58FDC6",
"totalHashes":"256.0","totalDiff":"2","recentNonce":"50","diff":"2",
"hps":"2475247"}
Adding a block
Setting response to Total Execution time to add to this block was 6 milliseconds
...{"selection":1,
"response":"Total Execution time to add to this block was 6 milliseconds"}
Adding a block
Setting response to Total Execution time to add to this block was 3 milliseconds
...{"selection":1,
"response":"Total Execution time to add to this block was 3 milliseconds"}
Adding a block
Setting response to Total Execution time to add to this block was 1 milliseconds
...{"selection":1,
"response":"Total Execution time to add to this block was 1 milliseconds"}
Verifying entire chain
Chain Verification: TRUE
Total execution time required to verify the chain was 0 milliseconds
Setting response to Total execution time to verify the chain was 0 milliseconds
View the Blockchain
Setting response to {"ds_chain":
"["{"index":0,"time stamp ":"2022-10-31 03:09:53.721","Tx ":"Genesis",
"PrevHash ":"","nonce":50,"difficulty":2}",
"{"index":1,"time stamp ":"2022-10-31 03:10:09.158",
"Tx ":"Alice pays Bob 100DSCoin",
"PrevHash ":"00B3AF7E0A12DF2FE87007728AA78FFEB1478130CFDEAF0DCE8C1E378A58FDC6",
"nonce":135,"difficulty":2}",
"{"index":2,"time stamp ":"2022-10-31 03:10:22.94",
"Tx ":"Bob pays Carol 50DSCoin",
"PrevHash ":"00E39555ADA83C280660B575BA5D72F2DBE833292D4EF676AC6C94C9D41EEC06",
"nonce":67,"difficulty":2}",
"{"index":3,"time stamp ":"2022-10-31 03:10:34.685",
"Tx ":"Carol pays Donna 10 DSCoin",
"PrevHash ":"0090B614E9E3C0BEF7C4F493266CBF337DABFED379F9449650A9B12773F69A91",
"nonce":24,"difficulty":2}"]",
"chainHash":"00BB3DB92B60CADC4DD84CC80C82846E449411F359399DA99887E4C55911AFA6"}
Corrupt the Blockchain
Block 1 now holds Alice pays Bob 76 DScoin
Setting response to Block 1 now holds Alice pays Bob 76 DScoin
View the Blockchain
Setting response to {"ds_chain":
"["{"index":0,"time stamp ":"2022-10-31 03:09:53.721","Tx ":"Genesis",
"PrevHash ":"","nonce":50,"difficulty":2}",
"{"index":1,"time stamp ":"2022-10-31 03:10:09.158",
"Tx ":"Alice pays Bob 76 DScoin",
"PrevHash ":"00B3AF7E0A12DF2FE87007728AA78FFEB1478130CFDEAF0DCE8C1E378A58FDC6",
"nonce":135,"difficulty":2}",
"{"index":2,"time stamp ":"2022-10-31 03:10:22.94",
"Tx ":"Bob pays Carol 50DSCoin",
"PrevHash ":"00E39555ADA83C280660B575BA5D72F2DBE833292D4EF676AC6C94C9D41EEC06",
"nonce":67,"difficulty":2}",
"{"index":3,"time stamp ":"2022-10-31 03:10:34.685",
"Tx ":"Carol pays Donna 10 DSCoin",
"PrevHash ":"0090B614E9E3C0BEF7C4F493266CBF337DABFED379F9449650A9B12773F69A91",
"nonce":24,"difficulty":2}"]",
"chainHash":"00BB3DB92B60CADC4DD84CC80C82846E449411F359399DA99887E4C55911AFA6"}
Verifying entire chain
Chain verification: FALSE
Improper hash on node 1 Does not begin with 00
Total execution time required to verify the chain was 1 milliseconds
Setting response to Total execution time to verify the chain was 1 milliseconds
Repairing the entire chain
Setting response to Total execution time required to repair the chain was 10
milliseconds
Verifying entire chain
Chain Verification: TRUE
Total execution time required to verify the chain was 0 milliseconds
Setting response to Total execution time to verify the chain was 0 milliseconds
Adding a block
Setting response to Total Execution time to add to this block was 204 milliseconds
...{"selection":1,"response":"Total Execution time to add to this block was 204 
milliseconds"}
Response: {"selection":1,"size":"5",
"chainHash":"0000A3A301A9A280EFB5F793C92EABF756E2ED2085B68C12A55F2369AEA78ADF",
"totalHashes":"66560.0","totalDiff":"12","recentNonce":"51812","diff":"4",
"hps":"2475247"}

### Task 1 Client Source Code


### Task 1 Server Source Code