diff --git a/bech32/bech32.go b/bech32/bech32.go index 7aa307d..fc2c063 100644 --- a/bech32/bech32.go +++ b/bech32/bech32.go @@ -348,3 +348,31 @@ func ConvertBits(data []byte, fromBits, toBits uint8, pad bool) ([]byte, error) return regrouped, nil } + +// EncodeFromBase256 converts a base256-encoded byte slice into a base32-encoded +// byte slice and then encodes it into a bech32 string with the given +// human-readable part (HRP). The HRP will be converted to lowercase if needed +// since mixed cased encodings are not permitted and lowercase is used for +// checksum purposes. +func EncodeFromBase256(hrp string, data []byte) (string, error) { + converted, err := ConvertBits(data, 8, 5, true) + if err != nil { + return "", err + } + return Encode(hrp, converted) +} + +// DecodeToBase256 decodes a bech32-encoded string into its associated +// human-readable part (HRP) and base32-encoded data, converts that data to a +// base256-encoded byte slice and returns it along with the lowercase HRP. +func DecodeToBase256(bech string) (string, []byte, error) { + hrp, data, err := Decode(bech) + if err != nil { + return "", nil, err + } + converted, err := ConvertBits(data, 5, 8, false) + if err != nil { + return "", nil, err + } + return hrp, converted, nil +} diff --git a/bech32/bech32_test.go b/bech32/bech32_test.go index f6fe773..9da0588 100644 --- a/bech32/bech32_test.go +++ b/bech32/bech32_test.go @@ -203,6 +203,173 @@ func TestCanDecodeUnlimtedBech32(t *testing.T) { } } +// TestBech32Base256 ensures decoding and encoding various bech32, HRPs, and +// data produces the expected results when using EncodeFromBase256 and +// DecodeToBase256. It includes tests for proper handling of case +// manipulations. +func TestBech32Base256(t *testing.T) { + tests := []struct { + name string // test name + encoded string // bech32 string to decode + hrp string // expected human-readable part + data string // expected hex-encoded data + err error // expected error + }{{ + name: "all uppercase, no data", + encoded: "A12UEL5L", + hrp: "a", + data: "", + }, { + name: "long hrp with separator and excluded chars, no data", + encoded: "an83characterlonghumanreadablepartthatcontainsthenumber1andtheexcludedcharactersbio1tt5tgs", + hrp: "an83characterlonghumanreadablepartthatcontainsthenumber1andtheexcludedcharactersbio", + data: "", + }, { + name: "6 char hrp with data with leading zero", + encoded: "abcdef1qpzry9x8gf2tvdw0s3jn54khce6mua7lmqqqxw", + hrp: "abcdef", + data: "00443214c74254b635cf84653a56d7c675be77df", + }, { + name: "hrp same as separator and max length encoded string", + encoded: "11qqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqc8247j", + hrp: "1", + data: "000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000", + }, { + name: "5 char hrp with data chosen to produce human-readable data part", + encoded: "split1checkupstagehandshakeupstreamerranterredcaperred2y9e3w", + hrp: "split", + data: "c5f38b70305f519bf66d85fb6cf03058f3dde463ecd7918f2dc743918f2d", + }, { + name: "same as previous but with checksum invalidated", + encoded: "split1checkupstagehandshakeupstreamerranterredcaperred2y9e2w", + err: ErrInvalidChecksum{"2y9e3w", "2y9e2w"}, + }, { + name: "hrp with invalid character (space)", + encoded: "s lit1checkupstagehandshakeupstreamerranterredcaperredp8hs2p", + err: ErrInvalidCharacter(' '), + }, { + name: "hrp with invalid character (DEL)", + encoded: "spl\x7ft1checkupstagehandshakeupstreamerranterredcaperred2y9e3w", + err: ErrInvalidCharacter(127), + }, { + name: "data part with invalid character (o)", + encoded: "split1cheo2y9e2w", + err: ErrNonCharsetChar('o'), + }, { + name: "data part too short", + encoded: "split1a2y9w", + err: ErrInvalidSeparatorIndex(5), + }, { + name: "empty hrp", + encoded: "1checkupstagehandshakeupstreamerranterredcaperred2y9e3w", + err: ErrInvalidSeparatorIndex(0), + }, { + name: "no separator", + encoded: "pzry9x0s0muk", + err: ErrInvalidSeparatorIndex(-1), + }, { + name: "too long by one char", + encoded: "11qqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqsqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqc8247j", + err: ErrInvalidLength(91), + }, { + name: "invalid due to mixed case in hrp", + encoded: "aBcdef1qpzry9x8gf2tvdw0s3jn54khce6mua7lmqqqxw", + err: ErrMixedCase{}, + }, { + name: "invalid due to mixed case in data part", + encoded: "abcdef1Qpzry9x8gf2tvdw0s3jn54khce6mua7lmqqqxw", + err: ErrMixedCase{}, + }} + + for _, test := range tests { + // Ensure the decode either produces an error or not as expected. + str := test.encoded + gotHRP, gotData, err := DecodeToBase256(str) + if test.err != err { + t.Errorf("%q: unexpected decode error -- got %v, want %v", + test.name, err, test.err) + continue + } + if err != nil { + // End test case here if a decoding error was expected. + continue + } + + // Ensure the expected HRP and original data are as expected. + if gotHRP != test.hrp { + t.Errorf("%q: mismatched decoded HRP -- got %q, want %q", test.name, + gotHRP, test.hrp) + continue + } + data, err := hex.DecodeString(test.data) + if err != nil { + t.Errorf("%q: invalid hex %q: %v", test.name, test.data, err) + continue + } + if !bytes.Equal(gotData, data) { + t.Errorf("%q: mismatched data -- got %x, want %x", test.name, + gotData, data) + continue + } + + // Encode the same data with the HRP converted to all uppercase and + // ensure the result is the lowercase version of the original encoded + // bech32 string. + gotEncoded, err := EncodeFromBase256(strings.ToUpper(test.hrp), data) + if err != nil { + t.Errorf("%q: unexpected uppercase HRP encode error: %v", test.name, + err) + } + wantEncoded := strings.ToLower(str) + if gotEncoded != wantEncoded { + t.Errorf("%q: mismatched encoding -- got %q, want %q", test.name, + gotEncoded, wantEncoded) + } + + // Encode the same data with the HRP converted to all lowercase and + // ensure the result is the lowercase version of the original encoded + // bech32 string. + gotEncoded, err = EncodeFromBase256(strings.ToLower(test.hrp), data) + if err != nil { + t.Errorf("%q: unexpected lowercase HRP encode error: %v", test.name, + err) + } + if gotEncoded != wantEncoded { + t.Errorf("%q: mismatched encoding -- got %q, want %q", test.name, + gotEncoded, wantEncoded) + } + + // Encode the same data with the HRP converted to mixed upper and + // lowercase and ensure the result is the lowercase version of the + // original encoded bech32 string. + var mixedHRPBuilder strings.Builder + for i, r := range test.hrp { + if i%2 == 0 { + mixedHRPBuilder.WriteString(strings.ToUpper(string(r))) + continue + } + mixedHRPBuilder.WriteRune(r) + } + gotEncoded, err = EncodeFromBase256(mixedHRPBuilder.String(), data) + if err != nil { + t.Errorf("%q: unexpected lowercase HRP encode error: %v", test.name, + err) + } + if gotEncoded != wantEncoded { + t.Errorf("%q: mismatched encoding -- got %q, want %q", test.name, + gotEncoded, wantEncoded) + } + + // Ensure a bit flip in the string is caught. + pos := strings.LastIndexAny(test.encoded, "1") + flipped := str[:pos+1] + string((str[pos+1] ^ 1)) + str[pos+2:] + _, _, err = DecodeToBase256(flipped) + if err == nil { + t.Error("expected decoding to fail") + } + } +} + // BenchmarkEncodeDecodeCycle performs a benchmark for a full encode/decode // cycle of a bech32 string. It also reports the allocation count, which we // expect to be 2 for a fully optimized cycle.