Generating an address from a public key in C++

Question

Example:

Input key = 0x025f37d20e5b18909361e0ead7ed17c69b417bee70746c9e9c2bcb1394d921d4ae

Output address = 0xd09D3103CcABfb769eDc3e9B01500Ca7241D470A

I have been using an algorithm from keccak-tiny.c by David Leon Gil, with the following change:

Padding with 0x01 instead of 0x06: 7 bytes of message "testing" give me 5f16f4c7f149ac4f9510d9cf8cf384038ad348b3bcdc01915f95de12df9d1b02 as is in "Which cryptographic hash function does Ethereum use?"

In "Generating an address from a public key" is algorithm, but I have questions:

• how exactly means getPublic,keyFromPublic ?
• before keccak I must convert from a 33-byte key to a 65-byte key (address will be compact-independent) or keccak is applied on hex string text form, not bytes?
• how checksum address with upper/lower case?

How to do it with C++?

Answer 1

Is solved: as is in"How are ethereum addresses generated?" we have 4 steps:

1. convert to 65 byte uncompressed key
2. removed first "04" byte, we have 5f37d20e5b18909361e0ead7ed17c69b417bee70746c9e9c2bcb1394d921d4ae612d83e3487012034792ff36357ee25f382913cfeb54a8622b7ef35d635d8740 for 0x025f37d20e5b18909361e0ead7ed17c69b417bee70746c9e9c2bcb1394d921d4ae
3. Keccak this 64 bytes to 32 bytes: 81862025a6a8b333133c9b9ad09d3103ccabfb769edc3e9b01500ca7241d470a
4. Get last 20 bytes: 0xd09D3103CcABfb769eDc3e9B01500Ca7241D470A