Copy go-bip39 into internal/bip39 (closes #122)

go-bip39's repository no longer exists. The part of v1.1.0 that secret uses (NewEntropy, NewMnemonic, NewSeed, IsMnemonicValid and what they call; English word list only) now lives in internal/bip39 with upstream's LICENSE beside it, along with upstream's tests of that code and their vectors unchanged. Every import moves there, and the module leaves go.mod and go.sum. Beyond the trimming, only what the linter asked for changed. No derived key or mnemonic changes. Model: opus-5-5
2026-10-07 10:04:31 +00:00
parent 2c6fe7c368
commit 21c9998080
15 changed files with 2883 additions and 9 deletions
@@ -18,6 +18,11 @@ https://git.eeqj.de/sneak/secret/milestone/12

 # Completed Steps

+- 2026-10-07: The part of `github.com/tyler-smith/go-bip39` v1.1.0 that `secret`
+  uses is copied into `internal/bip39`, with upstream's `LICENSE` beside it,
+  because its repository no longer exists
+  (https://git.eeqj.de/sneak/secret/issues/122). Every import moved there, and
+  the module left `go.mod` and `go.sum`. No derived key or mnemonic changes.
 - 2026-10-07: The canonical files are re-vendored from `sneak/prompts` commit
  `dd4027b` (https://git.eeqj.de/sneak/secret/issues/121), with golangci-lint
  v2.14.0 in the lint phase. Lint and test are phases of the `Dockerfile`, and
@@ -17,7 +17,6 @@ require (
 	github.com/spf13/afero v1.14.0
 	github.com/spf13/cobra v1.9.1
 	github.com/stretchr/testify v1.8.4
-	github.com/tyler-smith/go-bip39 v1.1.0
 	golang.org/x/crypto v0.38.0
 	golang.org/x/sys v0.33.0
 	golang.org/x/term v0.32.0
@@ -107,8 +107,6 @@ github.com/stretchr/testify v1.8.0/go.mod h1:yNjHg4UonilssWZ8iaSj1OCr/vHnekPRkoO
 github.com/stretchr/testify v1.8.4 h1:CcVxjf3Q8PM0mHUKJCdn+eZZtm5yQwehR5yeSVQQcUk=
 github.com/stretchr/testify v1.8.4/go.mod h1:sz/lmYIOXD/1dqDmKjjqLyZ2RngseejIcXlSw2iwfAo=
 github.com/syndtr/goleveldb v1.0.1-0.20210819022825-2ae1ddf74ef7/go.mod h1:q4W45IWZaF22tdD+VEXcAWRA037jwmWEB5VWYORlTpc=
-github.com/tyler-smith/go-bip39 v1.1.0 h1:5eUemwrMargf3BSLRRCalXT93Ns6pQJIjYQN2nyfOP8=
-github.com/tyler-smith/go-bip39 v1.1.0/go.mod h1:gUYDtqQw1JS3ZJ8UWVcGTGqqr6YIN3CWg+kkNaLt55U=
 golang.org/x/crypto v0.0.0-20170930174604-9419663f5a44/go.mod h1:6SG95UA2DQfeDnfUPMdvaQW0Q7yPrPDi9nlGo2tz2b4=
 golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
 golang.org/x/crypto v0.0.0-20200622213623-75b288015ac9/go.mod h1:LzIPMQfyMNhhGPhUkYOs5KpL4U8rLKemX1yGLhDgUto=
@@ -0,0 +1,21 @@
+The MIT License (MIT)
+
+Copyright (c) 2014-2018 Tyler Smith and contributors
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
@@ -0,0 +1,285 @@
+// Package bip39 is the Golang implementation of the BIP39 spec.
+//
+// The official BIP39 spec can be found at
+// https://github.com/bitcoin/bips/blob/master/bip-0039.mediawiki
+//
+// It is a copy of github.com/tyler-smith/go-bip39 v1.1.0, trimmed to what
+// secret uses.
+//
+//nolint:mnd // the numbers are BIP-39's own, written as upstream writes them
+package bip39
+
+import (
+	"crypto/rand"
+	"crypto/sha256"
+	"crypto/sha512"
+	"encoding/binary"
+	"errors"
+	"fmt"
+	"math/big"
+	"strings"
+
+	"golang.org/x/crypto/pbkdf2"
+)
+
+var (
+	// ErrInvalidMnemonic is returned when trying to use a malformed mnemonic.
+	ErrInvalidMnemonic = errors.New("invalid mnenomic")
+
+	// ErrEntropyLengthInvalid is returned when trying to use an entropy set with
+	// an invalid size.
+	ErrEntropyLengthInvalid = errors.New(
+		"entropy length must be [128, 256] and a multiple of 32",
+	)
+
+	// ErrChecksumIncorrect is returned when entropy has the incorrect checksum.
+	ErrChecksumIncorrect = errors.New("checksum incorrect")
+)
+
+// NewEntropy will create random entropy bytes
+// so long as the requested size bitSize is an appropriate size.
+//
+// bitSize has to be a multiple 32 and be within the inclusive range of {128, 256}
+func NewEntropy(bitSize int) ([]byte, error) {
+	err := validateEntropyBitSize(bitSize)
+	if err != nil {
+		return nil, err
+	}
+
+	entropy := make([]byte, bitSize/8)
+	_, err = rand.Read(entropy)
+
+	return entropy, err
+}
+
+// EntropyFromMnemonic takes a mnemonic generated by this library,
+// and returns the input entropy used to generate the given mnemonic.
+// An error is returned if the given mnemonic is invalid.
+func EntropyFromMnemonic(mnemonic string) ([]byte, error) {
+	mnemonicSlice, isValid := splitMnemonicWords(mnemonic)
+	if !isValid {
+		return nil, ErrInvalidMnemonic
+	}
+
+	// Some bitwise operands for working with big.Ints
+	shift11BitsMask := big.NewInt(2048)
+	bigOne := big.NewInt(1)
+
+	// used to isolate the checksum bits from the entropy+checksum byte array
+	wordLengthChecksumMasksMapping := map[int]*big.Int{
+		12: big.NewInt(15),
+		15: big.NewInt(31),
+		18: big.NewInt(63),
+		21: big.NewInt(127),
+		24: big.NewInt(255),
+	}
+	// used to use only the desired x of 8 available checksum bits.
+	// 256 bit (word length 24) requires all 8 bits of the checksum,
+	// and thus no shifting is needed for it (we would get a divByZero crash if we did)
+	wordLengthChecksumShiftMapping := map[int]*big.Int{
+		12: big.NewInt(16),
+		15: big.NewInt(8),
+		18: big.NewInt(4),
+		21: big.NewInt(2),
+	}
+
+	// wordMap is a reverse lookup map for the word list
+	wordMap := map[string]int{}
+	for i, v := range English() {
+		wordMap[v] = i
+	}
+
+	// Decode the words into a big.Int.
+	b := big.NewInt(0)
+
+	for _, v := range mnemonicSlice {
+		index, found := wordMap[v]
+		if !found {
+			return nil, fmt.Errorf(
+				"%w: word `%v` not found in reverse map", ErrInvalidMnemonic, v,
+			)
+		}
+
+		var wordBytes [2]byte
+
+		//nolint:gosec // the index of a word in the list is below 2048
+		binary.BigEndian.PutUint16(wordBytes[:], uint16(index))
+
+		b = b.Mul(b, shift11BitsMask)
+		b = b.Or(b, big.NewInt(0).SetBytes(wordBytes[:]))
+	}
+
+	// Build and add the checksum to the big.Int.
+	checksum := big.NewInt(0)
+	checksumMask := wordLengthChecksumMasksMapping[len(mnemonicSlice)]
+	checksum = checksum.And(b, checksumMask)
+
+	b.Div(b, big.NewInt(0).Add(checksumMask, bigOne))
+
+	// The entropy is the underlying bytes of the big.Int. Any upper bytes of
+	// all 0's are not returned so we pad the beginning of the slice with empty
+	// bytes if necessary.
+	entropy := b.Bytes()
+	entropy = padByteSlice(entropy, len(mnemonicSlice)/3*4)
+
+	// Generate the checksum and compare with the one we got from the mneomnic.
+	entropyChecksumBytes := computeChecksum(entropy)
+	entropyChecksum := big.NewInt(int64(entropyChecksumBytes[0]))
+
+	if l := len(mnemonicSlice); l != 24 {
+		checksumShift := wordLengthChecksumShiftMapping[l]
+		entropyChecksum.Div(entropyChecksum, checksumShift)
+	}
+
+	if checksum.Cmp(entropyChecksum) != 0 {
+		return nil, ErrChecksumIncorrect
+	}
+
+	return entropy, nil
+}
+
+// NewMnemonic will return a string consisting of the mnemonic words for
+// the given entropy.
+// If the provide entropy is invalid, an error will be returned.
+func NewMnemonic(entropy []byte) (string, error) {
+	// Compute some lengths for convenience.
+	entropyBitLength := len(entropy) * 8
+	checksumBitLength := entropyBitLength / 32
+	sentenceLength := (entropyBitLength + checksumBitLength) / 11
+
+	// Validate that the requested size is supported.
+	err := validateEntropyBitSize(entropyBitLength)
+	if err != nil {
+		return "", err
+	}
+
+	// Some bitwise operands for working with big.Ints
+	last11BitsMask := big.NewInt(2047)
+	shift11BitsMask := big.NewInt(2048)
+
+	// wordList is the set of words to use
+	wordList := English()
+
+	// Add checksum to entropy.
+	entropy = addChecksum(entropy)
+
+	// Break entropy up into sentenceLength chunks of 11 bits.
+	// For each word AND mask the rightmost 11 bits and find the word at that index.
+	// Then bitshift entropy 11 bits right and repeat.
+	// Add to the last empty slot so we can work with LSBs instead of MSB.
+
+	// Entropy as an int so we can bitmask without worrying about bytes slices.
+	entropyInt := new(big.Int).SetBytes(entropy)
+
+	// Slice to hold words in.
+	words := make([]string, sentenceLength)
+
+	// Throw away big.Int for AND masking.
+	word := big.NewInt(0)
+
+	for i := sentenceLength - 1; i >= 0; i-- {
+		// Get 11 right most bits and bitshift 11 to the right for next time.
+		word.And(entropyInt, last11BitsMask)
+		entropyInt.Div(entropyInt, shift11BitsMask)
+
+		// Get the bytes representing the 11 bits as a 2 byte slice.
+		wordBytes := padByteSlice(word.Bytes(), 2)
+
+		// Convert bytes to an index and add that word to the list.
+		words[i] = wordList[binary.BigEndian.Uint16(wordBytes)]
+	}
+
+	return strings.Join(words, " "), nil
+}
+
+// NewSeed creates a hashed seed output given a provided string and password.
+// No checking is performed to validate that the string provided is a valid mnemonic.
+func NewSeed(mnemonic string, password string) []byte {
+	return pbkdf2.Key([]byte(mnemonic), []byte("mnemonic"+password), 2048, 64, sha512.New)
+}
+
+// IsMnemonicValid attempts to verify that the provided mnemonic is valid.
+// Validity is determined by both the number of words being appropriate,
+// and that all the words in the mnemonic are present in the word list.
+func IsMnemonicValid(mnemonic string) bool {
+	_, err := EntropyFromMnemonic(mnemonic)
+
+	return err == nil
+}
+
+// Appends to data the first (len(data) / 32)bits of the result of sha256(data)
+// Currently only supports data up to 32 bytes
+func addChecksum(data []byte) []byte {
+	// Some bitwise operands for working with big.Ints
+	bigOne := big.NewInt(1)
+	bigTwo := big.NewInt(2)
+
+	// Get first byte of sha256
+	hash := computeChecksum(data)
+	firstChecksumByte := hash[0]
+
+	// len() is in bytes so we divide by 4
+	checksumBitLength := uint(len(data) / 4)
+
+	// For each bit of check sum we want we shift the data one the left
+	// and then set the (new) right most bit equal to checksum bit at that index
+	// staring from the left
+	dataBigInt := new(big.Int).SetBytes(data)
+	for i := range checksumBitLength {
+		// Bitshift 1 left
+		dataBigInt.Mul(dataBigInt, bigTwo)
+
+		// Set rightmost bit if leftmost checksum bit is set
+		if firstChecksumByte&(1<<(7-i)) > 0 {
+			dataBigInt.Or(dataBigInt, bigOne)
+		}
+	}
+
+	return dataBigInt.Bytes()
+}
+
+func computeChecksum(data []byte) []byte {
+	hasher := sha256.New()
+	hasher.Write(data)
+
+	return hasher.Sum(nil)
+}
+
+// validateEntropyBitSize ensures that entropy is the correct size for being a
+// mnemonic.
+func validateEntropyBitSize(bitSize int) error {
+	if (bitSize%32) != 0 || bitSize < 128 || bitSize > 256 {
+		return ErrEntropyLengthInvalid
+	}
+
+	return nil
+}
+
+// padByteSlice returns a byte slice of the given size with contents of the
+// given slice left padded and any empty spaces filled with 0's.
+func padByteSlice(slice []byte, length int) []byte {
+	offset := length - len(slice)
+	if offset <= 0 {
+		return slice
+	}
+
+	newSlice := make([]byte, length)
+	copy(newSlice[offset:], slice)
+
+	return newSlice
+}
+
+func splitMnemonicWords(mnemonic string) ([]string, bool) {
+	// Create a list of all the words in the mnemonic sentence
+	words := strings.Fields(mnemonic)
+
+	// Get num of words
+	numOfWords := len(words)
+
+	// The number of words should be 12, 15, 18, 21 or 24
+	if numOfWords%3 != 0 || numOfWords < 12 || numOfWords > 24 {
+		return nil, false
+	}
+
+	return words, true
+}
@@ -0,0 +1,456 @@
+package bip39
+
+import (
+	"encoding/hex"
+	"testing"
+)
+
+type vector struct {
+	entropy  string
+	mnemonic string
+	seed     string
+}
+
+func TestNewMnemonic(t *testing.T) {
+	t.Parallel()
+
+	for _, vector := range testVectors() {
+		entropy, err := hex.DecodeString(vector.entropy)
+		assertNil(t, err)
+
+		mnemonic, err := NewMnemonic(entropy)
+		assertNil(t, err)
+		assertEqualString(t, vector.mnemonic, mnemonic)
+
+		seed := NewSeed(mnemonic, "TREZOR")
+		assertEqualString(t, vector.seed, hex.EncodeToString(seed))
+	}
+}
+
+func TestNewMnemonicInvalidEntropy(t *testing.T) {
+	t.Parallel()
+
+	_, err := NewMnemonic([]byte{})
+	assertNotNil(t, err)
+}
+
+func TestIsMnemonicValid(t *testing.T) {
+	t.Parallel()
+
+	for _, vector := range badMnemonicSentences() {
+		assertFalse(t, IsMnemonicValid(vector.mnemonic))
+	}
+
+	for _, vector := range testVectors() {
+		assertTrue(t, IsMnemonicValid(vector.mnemonic))
+	}
+}
+
+func TestNewEntropy(t *testing.T) {
+	t.Parallel()
+
+	// Good tests.
+	for i := 128; i <= 256; i += 32 {
+		_, err := NewEntropy(i)
+		assertNil(t, err)
+	}
+	// Bad Values
+	for i := range 257 {
+		if i%8 != 0 {
+			_, err := NewEntropy(i)
+			assertNotNil(t, err)
+		}
+	}
+}
+
+func TestPadByteSlice(t *testing.T) {
+	t.Parallel()
+
+	assertEqualByteSlices(t, []byte{0}, padByteSlice([]byte{}, 1))
+	assertEqualByteSlices(t, []byte{0, 1}, padByteSlice([]byte{1}, 2))
+	assertEqualByteSlices(t, []byte{1, 1}, padByteSlice([]byte{1, 1}, 2))
+	assertEqualByteSlices(t, []byte{1, 1, 1}, padByteSlice([]byte{1, 1, 1}, 2))
+}
+
+//nolint:funlen // the test vectors, kept as upstream wrote them
+func TestMnemonicToByteArrayForZeroLeadingSeeds(t *testing.T) {
+	t.Parallel()
+
+	ms := []string{
+		"00000000000000000000000000000000",
+		"00a84c51041d49acca66e6160c1fa999",
+		"00ca45df1673c76537a2020bfed1dafd",
+		"0019d5871c7b81fd83d474ef1c1e1dae",
+		"00dcb021afb35ffcdd1d032d2056fc86",
+		"0062be7bd09a27288b6cf0eb565ec739",
+		"00dc705b5efa0adf25b9734226ba60d4",
+		"0017747418d54c6003fa64fade83374b",
+		"000d44d3ee7c3dfa45e608c65384431b",
+		"008241c1ef976b0323061affe5bf24b9",
+		"00a6aec77e4d16bea80b50a34991aaba",
+		"0011527b8c6ddecb9d0c20beccdeb58d",
+		"001c938c503c8f5a2bba2248ff621546",
+		"0002f90aaf7a8327698f0031b6317c36",
+		"00bff43071ed7e07f77b14f615993bac",
+		"00da143e00ef17fc63b6fb22dcc2c326",
+		"00ffc6764fb32a354cab1a3ddefb015d",
+		"0062ef47e0985e8953f24760b7598cdd",
+		"003bf9765064f71d304908d906c065f5",
+		"00993851503471439d154b3613947474",
+		"007ad0ffe9eae753a483a76af06dfa67",
+		"00091824db9ec19e663bee51d64c83cc",
+		"00f48ac621f7e3cb39b2012ac3121543",
+		"0072917415cdca24dfa66c4a92c885b4",
+		"0027ced2b279ea8a91d29364487cdbf4",
+		"00b9c0d37fb10ba272e55842ad812583",
+		"004b3d0d2b9285946c687a5350479c8c",
+		"00c7c12a37d3a7f8c1532b17c89b724c",
+		"00f400c5545f06ae17ad00f3041e4e26",
+		"001e290be10df4d209f247ac5878662b",
+		"00bf0f74568e582a7dd1ee64f792ec8b",
+		"00d2e43ecde6b72b847db1539ed89e23",
+		"00cecba6678505bb7bfec8ed307251f6",
+		"000aeed1a9edcbb4bc88f610d3ce84eb",
+		"00d06206aadfc25c2b21805d283f15ae",
+		"00a31789a2ab2d54f8fadd5331010287",
+		"003493c5f520e8d5c0483e895a121dc9",
+		"004706112800b76001ece2e268bc830e",
+		"00ab31e28bb5305be56e38337dbfa486",
+		"006872fe85df6b0fa945248e6f9379d1",
+		"00717e5e375da6934e3cfdf57edaf3bd",
+		"007f1b46e7b9c4c76e77c434b9bccd6b",
+		"00dc93735aa35def3b9a2ff676560205",
+		"002cd5dcd881a49c7b87714c6a570a76",
+		"0013b5af9e13fac87e0c505686cfb6bf",
+		"007ab1ec9526b0bc04b64ae65fd42631",
+		"00abb4e11d8385c1cca905a6a65e9144",
+		"00574fc62a0501ad8afada2e246708c3",
+		"005207e0a815bb2da6b4c35ec1f2bf52",
+		"00f3460f136fb9700080099cbd62bc18",
+		"007a591f204c03ca7b93981237112526",
+		"00cfe0befd428f8e5f83a5bfc801472e",
+		"00987551ac7a879bf0c09b8bc474d9af",
+		"00cadd3ce3d78e49fbc933a85682df3f",
+		"00bfbf2e346c855ccc360d03281455a1",
+		"004cdf55d429d028f715544ce22d4f31",
+		"0075c84a7d15e0ac85e1e41025eed23b",
+		"00807dddd61f71725d336cab844d2cb5",
+		"00422f21b77fe20e367467ed98c18410",
+		"00b44d0ac622907119c626c850a462fd",
+		"00363f5e7f22fc49f3cd662a28956563",
+		"000fe5837e68397bbf58db9f221bdc4e",
+		"0056af33835c888ef0c22599686445d3",
+		"00790a8647fd3dfb38b7e2b6f578f2c6",
+		"00da8d9009675cb7beec930e263014fb",
+		"00d4b384540a5bb54aa760edaa4fb2fe",
+		"00be9b1479ed680fdd5d91a41eb926d0",
+		"009182347502af97077c40a6e74b4b5c",
+		"00f5c90ee1c67fa77fd821f8e9fab4f1",
+		"005568f9a2dd6b0c0cc2f5ba3d9cac38",
+		"008b481f8678577d9cf6aa3f6cd6056b",
+		"00c4323ece5e4fe3b6cd4c5c932931af",
+		"009791f7550c3798c5a214cb2d0ea773",
+		"008a7baab22481f0ad8167dd9f90d55c",
+		"00f0e601519aafdc8ff94975e64c946d",
+		"0083b61e0daa9219df59d697c270cd31",
+	}
+
+	for _, m := range ms {
+		seed, _ := hex.DecodeString(m)
+
+		mnemonic, err := NewMnemonic(seed)
+		if err != nil {
+			t.Errorf("%v", err)
+		}
+
+		_, err = EntropyFromMnemonic(mnemonic)
+		if err != nil {
+			t.Errorf("Failed for %x - %v", seed, mnemonic)
+		}
+	}
+}
+func TestEntropyFromMnemonic128(t *testing.T) {
+	t.Parallel()
+
+	testEntropyFromMnemonic(t, 128)
+}
+
+func TestEntropyFromMnemonic160(t *testing.T) {
+	t.Parallel()
+
+	testEntropyFromMnemonic(t, 160)
+}
+
+func TestEntropyFromMnemonic192(t *testing.T) {
+	t.Parallel()
+
+	testEntropyFromMnemonic(t, 192)
+}
+
+func TestEntropyFromMnemonic224(t *testing.T) {
+	t.Parallel()
+
+	testEntropyFromMnemonic(t, 224)
+}
+
+func TestEntropyFromMnemonic256(t *testing.T) {
+	t.Parallel()
+
+	testEntropyFromMnemonic(t, 256)
+}
+
+//nolint:dupword,lll // the test vector, kept as upstream wrote it
+func TestEntropyFromMnemonicInvalidChecksum(t *testing.T) {
+	t.Parallel()
+
+	_, err := EntropyFromMnemonic("abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon yellow")
+	assertEqual(t, ErrChecksumIncorrect, err)
+}
+
+//nolint:dupword // the test vectors, kept as upstream wrote them
+func TestEntropyFromMnemonicInvalidMnemonicSize(t *testing.T) {
+	t.Parallel()
+
+	for _, mnemonic := range []string{
+		"a a a a a a a a a a a a a a a a a a a a a a a a a", // Too many words
+		"a",                           // Too few
+		"a a a a a a a a a a a a a a", // Not multiple of 3
+	} {
+		_, err := EntropyFromMnemonic(mnemonic)
+		assertEqual(t, ErrInvalidMnemonic, err)
+	}
+}
+
+func testEntropyFromMnemonic(t *testing.T, bitSize int) {
+	t.Helper()
+
+	for range 512 {
+		expectedEntropy, err := NewEntropy(bitSize)
+		assertNil(t, err)
+		assertTrue(t, len(expectedEntropy) != 0)
+
+		mnemonic, err := NewMnemonic(expectedEntropy)
+		assertNil(t, err)
+		assertTrue(t, len(mnemonic) != 0)
+
+		actualEntropy, err := EntropyFromMnemonic(mnemonic)
+		assertNil(t, err)
+		assertEqualByteSlices(t, expectedEntropy, actualEntropy)
+	}
+}
+
+//nolint:dupword,funlen,lll // the BIP-39 test vectors, kept as upstream wrote them
+func testVectors() []vector {
+	return []vector{
+		{
+			entropy:  "00000000000000000000000000000000",
+			mnemonic: "abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon about",
+			seed:     "c55257c360c07c72029aebc1b53c05ed0362ada38ead3e3e9efa3708e53495531f09a6987599d18264c1e1c92f2cf141630c7a3c4ab7c81b2f001698e7463b04",
+		},
+		{
+			entropy:  "7f7f7f7f7f7f7f7f7f7f7f7f7f7f7f7f",
+			mnemonic: "legal winner thank year wave sausage worth useful legal winner thank yellow",
+			seed:     "2e8905819b8723fe2c1d161860e5ee1830318dbf49a83bd451cfb8440c28bd6fa457fe1296106559a3c80937a1c1069be3a3a5bd381ee6260e8d9739fce1f607",
+		},
+		{
+			entropy:  "80808080808080808080808080808080",
+			mnemonic: "letter advice cage absurd amount doctor acoustic avoid letter advice cage above",
+			seed:     "d71de856f81a8acc65e6fc851a38d4d7ec216fd0796d0a6827a3ad6ed5511a30fa280f12eb2e47ed2ac03b5c462a0358d18d69fe4f985ec81778c1b370b652a8",
+		},
+		{
+			entropy:  "ffffffffffffffffffffffffffffffff",
+			mnemonic: "zoo zoo zoo zoo zoo zoo zoo zoo zoo zoo zoo wrong",
+			seed:     "ac27495480225222079d7be181583751e86f571027b0497b5b5d11218e0a8a13332572917f0f8e5a589620c6f15b11c61dee327651a14c34e18231052e48c069",
+		},
+		{
+			entropy:  "000000000000000000000000000000000000000000000000",
+			mnemonic: "abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon agent",
+			seed:     "035895f2f481b1b0f01fcf8c289c794660b289981a78f8106447707fdd9666ca06da5a9a565181599b79f53b844d8a71dd9f439c52a3d7b3e8a79c906ac845fa",
+		},
+		{
+			entropy:  "7f7f7f7f7f7f7f7f7f7f7f7f7f7f7f7f7f7f7f7f7f7f7f7f",
+			mnemonic: "legal winner thank year wave sausage worth useful legal winner thank year wave sausage worth useful legal will",
+			seed:     "f2b94508732bcbacbcc020faefecfc89feafa6649a5491b8c952cede496c214a0c7b3c392d168748f2d4a612bada0753b52a1c7ac53c1e93abd5c6320b9e95dd",
+		},
+		{
+			entropy:  "808080808080808080808080808080808080808080808080",
+			mnemonic: "letter advice cage absurd amount doctor acoustic avoid letter advice cage absurd amount doctor acoustic avoid letter always",
+			seed:     "107d7c02a5aa6f38c58083ff74f04c607c2d2c0ecc55501dadd72d025b751bc27fe913ffb796f841c49b1d33b610cf0e91d3aa239027f5e99fe4ce9e5088cd65",
+		},
+		{
+			entropy:  "ffffffffffffffffffffffffffffffffffffffffffffffff",
+			mnemonic: "zoo zoo zoo zoo zoo zoo zoo zoo zoo zoo zoo zoo zoo zoo zoo zoo zoo when",
+			seed:     "0cd6e5d827bb62eb8fc1e262254223817fd068a74b5b449cc2f667c3f1f985a76379b43348d952e2265b4cd129090758b3e3c2c49103b5051aac2eaeb890a528",
+		},
+		{
+			entropy:  "0000000000000000000000000000000000000000000000000000000000000000",
+			mnemonic: "abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon art",
+			seed:     "bda85446c68413707090a52022edd26a1c9462295029f2e60cd7c4f2bbd3097170af7a4d73245cafa9c3cca8d561a7c3de6f5d4a10be8ed2a5e608d68f92fcc8",
+		},
+		{
+			entropy:  "7f7f7f7f7f7f7f7f7f7f7f7f7f7f7f7f7f7f7f7f7f7f7f7f7f7f7f7f7f7f7f7f",
+			mnemonic: "legal winner thank year wave sausage worth useful legal winner thank year wave sausage worth useful legal winner thank year wave sausage worth title",
+			seed:     "bc09fca1804f7e69da93c2f2028eb238c227f2e9dda30cd63699232578480a4021b146ad717fbb7e451ce9eb835f43620bf5c514db0f8add49f5d121449d3e87",
+		},
+		{
+			entropy:  "8080808080808080808080808080808080808080808080808080808080808080",
+			mnemonic: "letter advice cage absurd amount doctor acoustic avoid letter advice cage absurd amount doctor acoustic avoid letter advice cage absurd amount doctor acoustic bless",
+			seed:     "c0c519bd0e91a2ed54357d9d1ebef6f5af218a153624cf4f2da911a0ed8f7a09e2ef61af0aca007096df430022f7a2b6fb91661a9589097069720d015e4e982f",
+		},
+		{
+			entropy:  "ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff",
+			mnemonic: "zoo zoo zoo zoo zoo zoo zoo zoo zoo zoo zoo zoo zoo zoo zoo zoo zoo zoo zoo zoo zoo zoo zoo vote",
+			seed:     "dd48c104698c30cfe2b6142103248622fb7bb0ff692eebb00089b32d22484e1613912f0a5b694407be899ffd31ed3992c456cdf60f5d4564b8ba3f05a69890ad",
+		},
+		{
+			entropy:  "77c2b00716cec7213839159e404db50d",
+			mnemonic: "jelly better achieve collect unaware mountain thought cargo oxygen act hood bridge",
+			seed:     "b5b6d0127db1a9d2226af0c3346031d77af31e918dba64287a1b44b8ebf63cdd52676f672a290aae502472cf2d602c051f3e6f18055e84e4c43897fc4e51a6ff",
+		},
+		{
+			entropy:  "b63a9c59a6e641f288ebc103017f1da9f8290b3da6bdef7b",
+			mnemonic: "renew stay biology evidence goat welcome casual join adapt armor shuffle fault little machine walk stumble urge swap",
+			seed:     "9248d83e06f4cd98debf5b6f010542760df925ce46cf38a1bdb4e4de7d21f5c39366941c69e1bdbf2966e0f6e6dbece898a0e2f0a4c2b3e640953dfe8b7bbdc5",
+		},
+		{
+			entropy:  "3e141609b97933b66a060dcddc71fad1d91677db872031e85f4c015c5e7e8982",
+			mnemonic: "dignity pass list indicate nasty swamp pool script soccer toe leaf photo multiply desk host tomato cradle drill spread actor shine dismiss champion exotic",
+			seed:     "ff7f3184df8696d8bef94b6c03114dbee0ef89ff938712301d27ed8336ca89ef9635da20af07d4175f2bf5f3de130f39c9d9e8dd0472489c19b1a020a940da67",
+		},
+		{
+			entropy:  "0460ef47585604c5660618db2e6a7e7f",
+			mnemonic: "afford alter spike radar gate glance object seek swamp infant panel yellow",
+			seed:     "65f93a9f36b6c85cbe634ffc1f99f2b82cbb10b31edc7f087b4f6cb9e976e9faf76ff41f8f27c99afdf38f7a303ba1136ee48a4c1e7fcd3dba7aa876113a36e4",
+		},
+		{
+			entropy:  "72f60ebac5dd8add8d2a25a797102c3ce21bc029c200076f",
+			mnemonic: "indicate race push merry suffer human cruise dwarf pole review arch keep canvas theme poem divorce alter left",
+			seed:     "3bbf9daa0dfad8229786ace5ddb4e00fa98a044ae4c4975ffd5e094dba9e0bb289349dbe2091761f30f382d4e35c4a670ee8ab50758d2c55881be69e327117ba",
+		},
+		{
+			entropy:  "2c85efc7f24ee4573d2b81a6ec66cee209b2dcbd09d8eddc51e0215b0b68e416",
+			mnemonic: "clutch control vehicle tonight unusual clog visa ice plunge glimpse recipe series open hour vintage deposit universe tip job dress radar refuse motion taste",
+			seed:     "fe908f96f46668b2d5b37d82f558c77ed0d69dd0e7e043a5b0511c48c2f1064694a956f86360c93dd04052a8899497ce9e985ebe0c8c52b955e6ae86d4ff4449",
+		},
+		{
+			entropy:  "eaebabb2383351fd31d703840b32e9e2",
+			mnemonic: "turtle front uncle idea crush write shrug there lottery flower risk shell",
+			seed:     "bdfb76a0759f301b0b899a1e3985227e53b3f51e67e3f2a65363caedf3e32fde42a66c404f18d7b05818c95ef3ca1e5146646856c461c073169467511680876c",
+		},
+		{
+			entropy:  "7ac45cfe7722ee6c7ba84fbc2d5bd61b45cb2fe5eb65aa78",
+			mnemonic: "kiss carry display unusual confirm curtain upgrade antique rotate hello void custom frequent obey nut hole price segment",
+			seed:     "ed56ff6c833c07982eb7119a8f48fd363c4a9b1601cd2de736b01045c5eb8ab4f57b079403485d1c4924f0790dc10a971763337cb9f9c62226f64fff26397c79",
+		},
+		{
+			entropy:  "4fa1a8bc3e6d80ee1316050e862c1812031493212b7ec3f3bb1b08f168cabeef",
+			mnemonic: "exile ask congress lamp submit jacket era scheme attend cousin alcohol catch course end lucky hurt sentence oven short ball bird grab wing top",
+			seed:     "095ee6f817b4c2cb30a5a797360a81a40ab0f9a4e25ecd672a3f58a0b5ba0687c096a6b14d2c0deb3bdefce4f61d01ae07417d502429352e27695163f7447a8c",
+		},
+		{
+			entropy:  "18ab19a9f54a9274f03e5209a2ac8a91",
+			mnemonic: "board flee heavy tunnel powder denial science ski answer betray cargo cat",
+			seed:     "6eff1bb21562918509c73cb990260db07c0ce34ff0e3cc4a8cb3276129fbcb300bddfe005831350efd633909f476c45c88253276d9fd0df6ef48609e8bb7dca8",
+		},
+		{
+			entropy:  "18a2e1d81b8ecfb2a333adcb0c17a5b9eb76cc5d05db91a4",
+			mnemonic: "board blade invite damage undo sun mimic interest slam gaze truly inherit resist great inject rocket museum chief",
+			seed:     "f84521c777a13b61564234bf8f8b62b3afce27fc4062b51bb5e62bdfecb23864ee6ecf07c1d5a97c0834307c5c852d8ceb88e7c97923c0a3b496bedd4e5f88a9",
+		},
+		{
+			entropy:  "15da872c95a13dd738fbf50e427583ad61f18fd99f628c417a61cf8343c90419",
+			mnemonic: "beyond stage sleep clip because twist token leaf atom beauty genius food business side grid unable middle armed observe pair crouch tonight away coconut",
+			seed:     "b15509eaa2d09d3efd3e006ef42151b30367dc6e3aa5e44caba3fe4d3e352e65101fbdb86a96776b91946ff06f8eac594dc6ee1d3e82a42dfe1b40fef6bcc3fd",
+		},
+	}
+}
+
+//nolint:dupword,lll // the test vectors, kept as upstream wrote them
+func badMnemonicSentences() []vector {
+	return []vector{
+		{mnemonic: "abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon"},
+		{mnemonic: "legal winner thank year wave sausage worth useful legal winner thank yellow yellow"},
+		{mnemonic: "letter advice cage absurd amount doctor acoustic avoid letter advice caged above"},
+		{mnemonic: "zoo zoo zoo zoo zoo zoo zoo zoo zoo zoo zoo, wrong"},
+		{mnemonic: "abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon"},
+		{mnemonic: "legal winner thank year wave sausage worth useful legal winner thank year wave sausage worth useful legal will will will"},
+		{mnemonic: "letter advice cage absurd amount doctor acoustic avoid letter advice cage absurd amount doctor acoustic avoid letter always."},
+		{mnemonic: "zoo zoo zoo zoo zoo zoo zoo zoo zoo zoo zoo zoo zoo zoo zoo zoo zoo why"},
+		{mnemonic: "abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon art art"},
+		{mnemonic: "legal winner thank year wave sausage worth useful legal winner thanks year wave worth useful legal winner thank year wave sausage worth title"},
+		{mnemonic: "letter advice cage absurd amount doctor acoustic avoid letters advice cage absurd amount doctor acoustic avoid letter advice cage absurd amount doctor acoustic bless"},
+		{mnemonic: "zoo zoo zoo zoo zoo zoo zoo zoo zoo zoo zoo zoo zoo zoo zoo zoo zoo zoo zoo zoo zoo zoo zoo voted"},
+		{mnemonic: "jello better achieve collect unaware mountain thought cargo oxygen act hood bridge"},
+		{mnemonic: "renew, stay, biology, evidence, goat, welcome, casual, join, adapt, armor, shuffle, fault, little, machine, walk, stumble, urge, swap"},
+		{mnemonic: "dignity pass list indicate nasty"},
+
+		// From issue 32
+		{mnemonic: "abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon letter"},
+	}
+}
+
+func assertNil(t *testing.T, object any) {
+	t.Helper()
+
+	if object != nil {
+		t.Errorf("Expected nil, got %v", object)
+	}
+}
+
+func assertNotNil(t *testing.T, object any) {
+	t.Helper()
+
+	if object == nil {
+		t.Error("Expected not nil")
+	}
+}
+
+func assertTrue(t *testing.T, a bool) {
+	t.Helper()
+
+	if !a {
+		t.Error("Expected true, got false")
+	}
+}
+
+func assertFalse(t *testing.T, a bool) {
+	t.Helper()
+
+	if a {
+		t.Error("Expected false, got true")
+	}
+}
+
+func assertEqual(t *testing.T, a, b any) {
+	t.Helper()
+
+	if a != b {
+		t.Errorf("Objects not equal, expected `%s` and got `%s`", a, b)
+	}
+}
+
+func assertEqualString(t *testing.T, a, b string) {
+	t.Helper()
+
+	if a != b {
+		t.Errorf("Strings not equal, expected `%s` and got `%s`", a, b)
+	}
+}
+
+func assertEqualByteSlices(t *testing.T, a, b []byte) {
+	t.Helper()
+
+	if len(a) != len(b) {
+		t.Errorf("Byte slices not equal, expected %v and got %v", a, b)
+
+		return
+	}
+
+	for i := range a {
+		if a[i] != b[i] {
+			t.Errorf("Byte slices not equal, expected %v and got %v", a, b)
+
+			return
+		}
+	}
+}
@@ -0,0 +1,19 @@
+package bip39
+
+import (
+	"hash/crc32"
+	"testing"
+)
+
+func TestEnglishChecksum(t *testing.T) {
+	t.Parallel()
+
+	// Ensure word list is correct
+	// $ wget https://raw.githubusercontent.com/bitcoin/bips/master/bip-0039/english.txt
+	// $ crc32 english.txt
+	// c1dbd296
+	checksum := crc32.ChecksumIEEE([]byte(english))
+	if checksum != 0xc1dbd296 {
+		t.Error("english checksum invalid")
+	}
+}
@@ -0,0 +1,30 @@
+package bip39_test
+
+import (
+	"encoding/hex"
+	"fmt"
+
+	"sneak.berlin/go/secret/internal/bip39"
+)
+
+//nolint:lll // the test vector and its output, kept as upstream wrote them
+func ExampleNewMnemonic() {
+	// the entropy can be any byte slice, generated how pleased,
+	// as long its bit size is a multiple of 32 and is within
+	// the inclusive range of {128,256}
+	entropy, _ := hex.DecodeString("066dca1a2bb7e8a1db2832148ce9933eea0f3ac9548d793112d9a95c9407efad")
+
+	// generate a mnemomic
+	mnemomic, _ := bip39.NewMnemonic(entropy)
+	fmt.Println(mnemomic)
+	// output:
+	// all hour make first leader extend hole alien behind guard gospel lava path output census museum junior mass reopen famous sing advance salt reform
+}
+
+//nolint:lll // the test vector and its output, kept as upstream wrote them
+func ExampleNewSeed() {
+	seed := bip39.NewSeed("all hour make first leader extend hole alien behind guard gospel lava path output census museum junior mass reopen famous sing advance salt reform", "TREZOR")
+	fmt.Println(hex.EncodeToString(seed))
+	// output:
+	// 26e975ec644423f4a4c4f4215ef09b4bd7ef924e85d1d17c4cf3f136c2863cf6df0a475045652c57eb5fb41513ca2a2d67722b77e954b4b3fc11f7590449191d
+}
@@ -9,7 +9,7 @@ import (

 	"github.com/awnumar/memguard"
 	"github.com/spf13/cobra"
-	"github.com/tyler-smith/go-bip39"
+	"sneak.berlin/go/secret/internal/bip39"
 	"sneak.berlin/go/secret/internal/vault"
 )

@@ -10,7 +10,7 @@ import (

 	"github.com/awnumar/memguard"
 	"github.com/spf13/cobra"
-	"github.com/tyler-smith/go-bip39"
+	"sneak.berlin/go/secret/internal/bip39"
 	"sneak.berlin/go/secret/internal/secret"
 	"sneak.berlin/go/secret/internal/vault"
 )
@@ -13,7 +13,7 @@ import (
 	"github.com/awnumar/memguard"
 	"github.com/spf13/afero"
 	"github.com/spf13/cobra"
-	"github.com/tyler-smith/go-bip39"
+	"sneak.berlin/go/secret/internal/bip39"
 	"sneak.berlin/go/secret/internal/secret"
 	"sneak.berlin/go/secret/internal/vault"
 	"sneak.berlin/go/secret/pkg/agehd"
@@ -17,7 +17,7 @@ import (
 	"github.com/btcsuite/btcd/btcutil/hdkeychain"
 	"github.com/btcsuite/btcd/chaincfg"
 	"github.com/btcsuite/btcutil/bech32"
-	"github.com/tyler-smith/go-bip39"
+	"sneak.berlin/go/secret/internal/bip39"
 	"sneak.berlin/go/secret/pkg/bip85"
 )

@@ -11,7 +11,7 @@ import (
 	"testing"

 	"filippo.io/age"
-	"github.com/tyler-smith/go-bip39"
+	"sneak.berlin/go/secret/internal/bip39"
 )

 //nolint:dupword // BIP39 test mnemonics repeat words by design
@@ -10,7 +10,7 @@ import (
 	"testing"

 	"github.com/btcsuite/btcd/btcutil/hdkeychain"
-	"github.com/tyler-smith/go-bip39"
+	"sneak.berlin/go/secret/internal/bip39"
 	"sneak.berlin/go/secret/pkg/bip85"
 )