!! now it adds up! why do i always mess up between nibbles and bytes!! 
Topic: bitcoin address calculation deep dive, does not add up (Read 491 times)
THANKS for both of you guys !! now it adds up! why do i always mess up between nibbles and bytes!!
!! now it adds up! why do i always mess up between nibbles and bytes!! 
BitcoinAddress=base58encode( 2 bytes version + 20 bytes output from RIPEMD160(SHA256(pubkey)) + 4 bytes checksum)
Are you sure about that? I thought:
BitcoinAddress=base58encode( 1 bytes version + 20 bytes output from RIPEMD160(SHA256(pubkey)) + 4 bytes checksum)
1 + 20 + 4 = 25 bytes
Since 1 byte = 8 bits...
25 * 8 = 200 bits
base58encode(25 bytes) = base58encode(200 bits)
200 bits / [ log(58) / log(2) ] = 200 bits / 5.85798... = 34.14 base58 digits
base58encode(26 bytes)=base58encode(104 bits)
I think you'll find 26 bytes is actually 208 bits. 
Looking through mastering bitcoin book's chapters, I get the following formula for bitcoin address generation:
BitcoinAddress=base58encode( 2 bytes version + 20 bytes output from RIPEMD160(SHA256(pubkey)) + 4 bytes checksum)
= base58encode(26 bytes)=base58encode(104 bits) however this is generating base58 digit size of
104bits / ((log(58)/log(2)) = 104bits/5.8579...=17.75 base58 digits.
Why 104bits / (log(58)/log(2))?
Suppose 256-bits address and how many hexes are there if represented by hex? 256 / ((log 16) / log(2)) = 256/4 = 64 hex digits.
But when I check several bitcoin wallet address the base58encoded address they are showing is 34 base58 digits. Definitely not adding up or I am missing something here.
BitcoinAddress=base58encode( 2 bytes version + 20 bytes output from RIPEMD160(SHA256(pubkey)) + 4 bytes checksum)
= base58encode(26 bytes)=base58encode(104 bits) however this is generating base58 digit size of
104bits / ((log(58)/log(2)) = 104bits/5.8579...=17.75 base58 digits.
Why 104bits / (log(58)/log(2))?
Suppose 256-bits address and how many hexes are there if represented by hex? 256 / ((log 16) / log(2)) = 256/4 = 64 hex digits.
But when I check several bitcoin wallet address the base58encoded address they are showing is 34 base58 digits. Definitely not adding up or I am missing something here.
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