With the help of bitcoin wiki I learned that every bitcoin address stands for a number and that shorter addresses are valid just because they happen to start with zeros, and when the zeroes are omitted, the encoded address gets shorter.

Source: https://en.bitcoin.it/wiki/Address

I am not sure I fully understood everything. First of all, I suppose the part about a "bitcoin address stands for a number" refers to hexadecimal digits?

Other point I'd like to clarify:

How the zeros can appear while address is generated in the first place? I thought that zeros (along with l, I and O) does not exist in Base58Check encoding at all.

1 Answer 1


Bitcoin addresses are 160bit numbers. They are derived by running the public key through hash functions. The result is a number in a fixed range i.e. 0 to 2^160. This is then encoded in base58check or bech32. You could represent it as hexadecimal as well if you liked.

2 and 53 are both random numbers inside 0-100. One takes 1 character to write out while the other takes 2 characters to write out. Instead of writing them in the decimal number system I could write them in hexadecimal and that would not change.

Base58check is just another encoding format. It's converting the number into base 58 number system and adding a checksum at the end to prevent typos.

You can represent zeroes in all of the above number systems/encoding formats. You may do it with characters other than 0 though. In the case of base58check 0 is represented with 1.

  • Thank you. Could you also clarify how bitcoin address gets "1" at the start? I've read this Technical_background_of_version_1_Bitcoin_addresses . In the end we can see that two 0 are added before encoding into base58check. Why we have only one "1" instead of two "1". The table you provided says that 0 converts to 1.
    – D-Samp
    Sep 12, 2018 at 13:43
  • see number 5 here
    – Abdussamad
    Sep 12, 2018 at 17:57

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.