clawbot
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check / check (push) Waiting to run
The key index, --words, the --to recipients and the input file of age encrypt and age decrypt were checked only after the mnemonic had been obtained, so a run that could not succeed still prompted for it or ran the mnemonic command. options.Index now refuses an index above derive.MaxIndex, which covers every command group; the mnemonic command calls the new childmnemonic.CheckWords first; age encrypt reads its recipients with the new agekey.Recipients, and both age commands open their input, before the key is derived. The README says which checks come first. Judgement call: the -o path is still looked at after the mnemonic. Model: opus-5-5
74 lines
1.9 KiB
Go
74 lines
1.9 KiB
Go
// Package childmnemonic derives a mnemonic from another mnemonic.
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package childmnemonic
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import (
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"errors"
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"fmt"
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"github.com/btcsuite/btcd/btcutil/hdkeychain"
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"sneak.berlin/go/keyfunc/internal/bip39"
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"sneak.berlin/go/keyfunc/internal/derive"
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"sneak.berlin/go/secret/pkg/bip85"
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)
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// english is the number BIP-85 gives the English word list.
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const english = 0
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// The lengths a child mnemonic may have. BIP-85 also allows 15 and 21
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// words; these three are the ones this tool offers.
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const (
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twelve = 12
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eighteen = 18
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twentyFour = 24
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)
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// DefaultWords is how long a child mnemonic is when the user does not
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// say.
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const DefaultWords = twelve
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// ErrWordCount is returned for a length this tool does not offer.
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var ErrWordCount = errors.New("a child mnemonic has 12, 18 or 24 words")
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// CheckWords refuses a length this tool does not offer, so that the
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// command can turn it down before it looks for the mnemonic.
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func CheckWords(words uint32) error {
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switch words {
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case twelve, eighteen, twentyFour:
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return nil
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default:
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return fmt.Errorf("%w, not %d", ErrWordCount, words)
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}
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}
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// Derive returns the English child mnemonic of that many words at that
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// key index, taken from the master key with BIP-85's own mnemonic
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// application, number 39. The words come straight from the BIP-85
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// entropy, cut to the length the word count needs, rather than from
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// the generator the other key types read their bytes from.
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func Derive(
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master *hdkeychain.ExtendedKey,
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words, index uint32,
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) (string, error) {
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err := CheckWords(words)
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if err != nil {
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return "", err
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}
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err = derive.CheckIndex(index)
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if err != nil {
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return "", err
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}
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entropy, err := bip85.DeriveBIP39Entropy(master, english, words, index)
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if err != nil {
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return "", fmt.Errorf("deriving entropy: %w", err)
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}
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child, err := bip39.NewMnemonic(entropy)
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if err != nil {
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return "", fmt.Errorf("turning the entropy into words: %w", err)
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}
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return child, nil
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}
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