Final Assessment
What are the 3 main differences between hashing and encryption? a) message delivery, collision resistance, and packet maintenance b) data loss, reversibility, and collision risk c) packet integrity, message delivery, and reversibility d) data loss, reversibility, and packet integrity \
What are the 3 important properties of ideal secure hash functions? a) preimage resistance, second preimage resistance, and data integrity b) collision resistance, preimage resistance, and second preimage resistance c) data integrity, data availability, and data confidentiality d) second preimage resistance, collision resistance, and data integrity \
Why is Base58 used in Bitcoin instead of the more common Base64? a) don't want 0OIl characters that look the same in some fonts b) could be used to create visually identical looking account numbers c) a string with non-alphanumeric characters is not as easily accepted as an account number d) e-mail usually won't line-break if there's no punctuation to break at f) doubleclicking selects the whole number as one word if it's all alphanumeric g) all of the above \
Using the hash calculator, find the checksum bytes in hexadecimal of the input string encoded in Base58Check checksum. \
Input String
Base58
Base58Check
Checksum
Any system is only as good as it is useful -Linus Torvalds
bXDBXzRN8ei3wRVRPByafBxTAp6osoZCijV6EomcSzx3mhp77vWzF6pbwkVJbj5eB2EdrbvyLFPBEUJ
4ttkt4iyNPZ3iXRg9cX3y5R2sJbBLsE5chrBZuYgbmQWPuGgV4M7CVrbuWvahpYQ4mwGSYQddw5dwRxrWV9LB
RxrWV9LB
5. What is HASH-256 used for in the Bitcoin system? a) calculating transaction fees b) It’s not used c) TXIDs, Merkle roots, and block headers d) encryption \
6. Calculate the big endian TXID for the following transaction:
01000000011e4bf9dc623d942fee4113e077f67204419cb6f841d98ebf250b698cbea8912b000000006b483045022100a7ce3b1d8cc852e625e5da3159131ba7ba071c7a93684f1d3b8d08b6dbc08e82022041ac850772b5877cc8b724f6a7a92709a65a17a52f78419b67304f2481526b79412102e8a1ab43a501a2ab84a14c5ef1a65c15add65f3ec8230e3fb63644a44ac71003ffffffff0200943577000000001976a914aa5604bae61cd60690dd9dec5efbb841668cb19288ac8f933577000000001976a914e33649e455368d536f6003b2908b6299df5fe8bf88ac00000000
Big Endian TXID
9a2d57528ed943eae34676928e52dc10623514f4420134ff791f64cb3f667875
7. List how many output UTXOs the following transaction has, and, using the hash calculator, find their satoshi values in decimal \
01000000011e4bf9dc623d942fee4113e077f67204419cb6f841d98ebf250b698cbea8912b000000006b483045022100a7ce3b1d8cc852e625e5da3159131ba7ba071c7a93684f1d3b8d08b6dbc08e82022041ac850772b5877cc8b724f6a7a92709a65a17a52f78419b67304f2481526b79412102e8a1ab43a501a2ab84a14c5ef1a65c15add65f3ec8230e3fb63644a44ac71003ffffffff0200943577000000001976a914aa5604bae61cd60690dd9dec5efbb841668cb19288ac8f933577000000001976a914e33649e455368d536f6003b2908b6299df5fe8bf88ac00000000
Number of UTXOs (in hex)
Value of first UTXO (in decimal)
Value of second UTXO
02
2000000000
1999999887
8. At what block depth do coinbase UTXOs become spendable? a) 1 b) 50 c) 100 d) 101 \
9. What are the 3 main parts of Merkle-Damgård hash functions? a) blocks, schedules, and outputs b) compression, schedules, and blocks c) preprocessing, compression, and final construction & output d) compression, preprocessing, and blocks \
10. How many satoshis exist in the Bitcoin system? a) 21,000,000 b) 21,000,000,000,000 c) 2,100,000,000,000,000 d) 2.1 x 106 \
11. How many rounds of compression does RIPEMD-160 have?
a) 100 b) 64 c) 128 d) 80 \
12. Using the hash calculator, Calculate the 33 byte compressed form of the following ECDSA public key
Public key x-coordinate
Public key y-coordinate
Compressed Public key in HEX
113664773391849625820845192611086427189289514738370038712289171739672026632191
76250103327783796662952791688177245826353020810702491301843418910254328042705
03fb4bfb5dd0be7093ba8ea643775af1ae05f05be1415da2d2cef997b33be14fff
13. Using the hash calculator, calculate the Bitcoin address from the compressed public key in question 12
Bitcoin Address
1QH1dpNvz7YMPA7CLNZwN4dAbKXH6YdeYh
14. Using the hash calculator, calculate the WIF for the follow private key \
Private key
WIF
5ee98fbc968fb9abd3bb98e0d7792080d62014aac3ea7245676716dcfca9e160
KzQD2FkVBJXE3m69eeWodG3oFQTuUA1kE2LNmAdCq77ksG1sCd5c
15. Using the hash calculator and a big number calculator, calculate Alice and Bob’s shared secret using Diffie-Hellman and Bitcoin’s 256bit 'n' value
Alice’s private key (HEX)
Bob’s private key (HEX)
Generator point 'g' (HEX)
2256 (DECIMAL)
fb4bfb5dd0be7093ba8ea643775af1ae05f05be1415da2d2cef997b33be14fff
6018da4bf909dfff872aff73b5c70e659a89a40f28112cbf4693e93eaffb181c
0279be667ef9dcbbac55a06295ce870b07029bfcdb2dce28d959f2815b16f81798
115792089237316195423570985008687907853269984665640564039457584007913129639936
Shared secret
(DECIMAL) 24926637309892526281343130463061454239891008796952183712849843310158704356192
371bfa0c42117a20da6483b2fd2ca5742c1bab39b4fbd3525c45157c33b12b60
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