module AdequateCryptoAddress::Utils::Bech32
Constants
- CHARSET
- CHARSET_REV
Public Class Methods
convert_bits(chunks, from_bits:, to_bits:, pad:)
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Utility for converting bytes of data between bases. These is used for BIP 173 address encoding/decoding to convert between sequences of bytes representing 8-bit values and groups of 5 bits. Conversions may be padded with trailing 0 bits to the nearest byte boundary. Returns nil if conversion requires padding and pad is false.
For example:
convert_bits("\xFF\xFF", from_bits: 8, to_bits: 5, pad: true) => "\x1F\x1F\x1F\10"
See github.com/bitcoin/bitcoin/blob/595a7bab23bc21049526229054ea1fff1a29c0bf/src/utilstrencodings.h#L154
# File lib/adequate_crypto_address/utils/bech32.rb, line 142 def convert_bits(chunks, from_bits:, to_bits:, pad:) output_mask = (1 << to_bits) - 1 buffer_mask = (1 << (from_bits + to_bits - 1)) - 1 buffer = 0 bits = 0 output = [] chunks.each do |chunk| buffer = ((buffer << from_bits) | chunk) & buffer_mask bits += from_bits while bits >= to_bits bits -= to_bits output << ((buffer >> bits) & output_mask) end end output << ((buffer << (to_bits - bits)) & output_mask) if pad && bits > 0 return nil if !pad && (bits >= from_bits || ((buffer << (to_bits - bits)) & output_mask) != 0) output end
decode(input)
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rubocop:disable CyclomaticComplexity,PerceivedComplexity
# File lib/adequate_crypto_address/utils/bech32.rb, line 72 def decode(input) chk = 1 input_len = input.bytesize have_lower = false have_upper = false return nil if input_len < 8 || input_len > 90 data_len = 0 data_len += 1 while data_len < input_len && input[(input_len - 1) - data_len] != '1' hrp_len = input_len - (1 + data_len) return nil if hrp_len < 1 || data_len < 6 hrp = [] hrp_len.times do |i| ch = input[i].ord return nil if ch < 33 || ch > 126 if ch >= 'a'.ord && ch <= 'z'.ord have_lower = true elsif ch >= 'A'.ord && ch <= 'Z'.ord have_upper = true ch = (ch - 'A'.ord) + 'a'.ord end hrp << ch chk = polymod_step(chk) ^ (ch >> 5) end chk = polymod_step(chk) hrp_len.times do |i| chk = polymod_step(chk) ^ (input[i].ord & 0x1f) end data = [] i = hrp_len + 1 while i < input_len ch = input[i].ord v = (ch & 0x80) != 0 ? -1 : CHARSET_REV[ch] have_lower = true if ch >= 'a'.ord && ch <= 'z'.ord have_upper = true if ch >= 'A'.ord && ch <= 'Z'.ord return nil if v == -1 chk = polymod_step(chk) ^ v data << v if (i + 6) < input_len i += 1 end return nil if have_lower && have_upper return nil if chk != 1 [hrp.pack('C*'), data] end
polymod_step(pre)
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# File lib/adequate_crypto_address/utils/bech32.rb, line 20 def polymod_step(pre) b = pre >> 25 ((pre & 0x1FFFFFF) << 5) ^ \ (-((b >> 0) & 1) & 0x3b6a57b2) ^ \ (-((b >> 1) & 1) & 0x26508e6d) ^ \ (-((b >> 2) & 1) & 0x1ea119fa) ^ \ (-((b >> 3) & 1) & 0x3d4233dd) ^ \ (-((b >> 4) & 1) & 0x2a1462b3) end