update the license files to make go do happy

feat: rename Discriminant to Algorithm
feat(doc): add some basic examples
2025-08-05 15:46:53 +02:00 · 2025-08-05 15:41:30 +02:00 · 2025-08-05 15:36:36 +02:00 · 2025-07-29 15:22:15 +02:00 · 2025-07-28 20:41:02 +02:00
19 changed files with 304 additions and 705 deletions
--- a/25
+++ b/25
@@ -1,25 +0,0 @@
-The contents of this repository are Copyright (c) corresponding authors and
-contributors, licensed under the `Permissive License Stack` meaning either of:
-
- Apache-2.0 Software License: https://www.apache.org/licenses/LICENSE-2.0
-  ([...4tr2kfsq](https://dweb.link/ipfs/bafkreiankqxazcae4onkp436wag2lj3ccso4nawxqkkfckd6cg4tr2kfsq))
-
- MIT Software License: https://opensource.org/licenses/MIT
-  ([...vljevcba](https://dweb.link/ipfs/bafkreiepofszg4gfe2gzuhojmksgemsub2h4uy2gewdnr35kswvljevcba))
-
-You may not use the contents of this repository except in compliance
-with one of the listed Licenses. For an extended clarification of the
-intent behind the choice of Licensing please refer to
-https://protocol.ai/blog/announcing-the-permissive-license-stack/
-
-Unless required by applicable law or agreed to in writing, software
-distributed under the terms listed in this notice is distributed on
-an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,
-either express or implied. See each License for the specific language
-governing permissions and limitations under that License.
-
-<!--- SPDX-License-Identifier: Apache-2.0 OR MIT -->
-
-`SPDX-License-Identifier: Apache-2.0 OR MIT`
-
-Verbatim copies of both licenses are included in the LICENSE-APACHE-2.0 and LICENSE-MIT files.
--- a/21
+++ b/21
@@ -1,21 +0,0 @@
-MIT License
-
-Copyright (c) 2025 UCAN Working Group - All rights reserved
-
-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.
--- a/LICENSE-APACHE-2.0
+++ b/LICENSE-APACHE-2.0
@@ -1,6 +1,35 @@
+The contents of this repository are Copyright (c) corresponding authors and
+contributors, licensed under the `Permissive License Stack` meaning either of:
+
+- Apache-2.0 Software License: https://www.apache.org/licenses/LICENSE-2.0
+  ([...4tr2kfsq](https://dweb.link/ipfs/bafkreiankqxazcae4onkp436wag2lj3ccso4nawxqkkfckd6cg4tr2kfsq))
+
+- MIT Software License: https://opensource.org/licenses/MIT
+  ([...vljevcba](https://dweb.link/ipfs/bafkreiepofszg4gfe2gzuhojmksgemsub2h4uy2gewdnr35kswvljevcba))
+
+You may not use the contents of this repository except in compliance
+with one of the listed Licenses. For an extended clarification of the
+intent behind the choice of Licensing please refer to
+https://protocol.ai/blog/announcing-the-permissive-license-stack/
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the terms listed in this notice is distributed on
+an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,
+either express or implied. See each License for the specific language
+governing permissions and limitations under that License.
+
+<!--- SPDX-License-Identifier: Apache-2.0 OR MIT -->
+
+`SPDX-License-Identifier: Apache-2.0 OR MIT`
+
+Verbatim copies of both licenses are included below:
+
+<details><summary>Apache-2.0 Software License</summary>
+
+```
                                 Apache License
                           Version 2.0, January 2004
-                        http://www.apache.org/licenses/
+                        https://www.apache.org/licenses/

   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION

@@ -174,28 +203,30 @@
      of your accepting any such warranty or additional liability.

   END OF TERMS AND CONDITIONS
+```

-   APPENDIX: How to apply the Apache License to your work.
+</details>

-      To apply the Apache License to your work, attach the following
-      boilerplate notice, with the fields enclosed by brackets "[]"
-      replaced with your own identifying information. (Don't include
-      the brackets!)  The text should be enclosed in the appropriate
-      comment syntax for the file format. We also recommend that a
-      file or class name and description of purpose be included on the
-      same "printed page" as the copyright notice for easier
-      identification within third-party archives.
+<details><summary>MIT Software License</summary>

-   Copyright 2025 UCAN Working Group - All right reserved
+```
+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:

-   Licensed under the Apache License, Version 2.0 (the "License");
-   you may not use this file except in compliance with the License.
-   You may obtain a copy of the License at
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.

-       http://www.apache.org/licenses/LICENSE-2.0
+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.
+```

-   Unless required by applicable law or agreed to in writing, software
-   distributed under the License is distributed on an "AS IS" BASIS,
-   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-   See the License for the specific language governing permissions and
-   limitations under the License.
+</details>
--- a/README.md
+++ b/README.md
@@ -1,9 +1,6 @@
 # go-varsig

-`go-varsig` implements the upcoming v1.0.0 release of the [`varsig` specification](https://github.com/ChainAgnostic/varsig/pull/18)
-with limited (and soon to be deprecated) support for the `varsig` < v1.0
-specification.  This is predominantly included to support the UCAN v1.0
-use-case.
+`go-varsig` is a go implementation of the [`varsig` specification](https://github.com/ChainAgnostic/varsig).

 Built with ❤️ by [Consensys](https://consensys.io/).

@@ -15,6 +12,43 @@ Include the `go-varsig` library by running the following command:
 go get github.com/ucan-wg/go-varsig@latest
 ```

+## Quickstart
+
+```go
+func ExampleDecode() {
+	example, err := base64.RawStdEncoding.DecodeString("NAHtAe0BE3E")
+	handleErr(err)
+
+	vs, err := varsig.Decode(example)
+	handleErr(err)
+
+	fmt.Printf("%T\n", vs)
+	fmt.Printf("Algorithm: %d\n", vs.Algorithm())
+	fmt.Printf("Hash: %d\n", vs.Hash())
+	fmt.Printf("PayloadEncoding: %d\n", vs.PayloadEncoding())
+
+	// Output:
+	// varsig.EdDSAVarsig
+	// Algorithm: 237
+	// Hash: 19
+	// PayloadEncoding: 3
+}
+
+func ExampleEncode() {
+	edDSAVarsig := varsig.NewEdDSAVarsig(
+		varsig.CurveEd25519,
+		varsig.HashSha2_512,
+		varsig.PayloadEncodingDAGCBOR,
+	)
+
+	b64 := base64.RawStdEncoding.EncodeToString(edDSAVarsig.Encode())
+	fmt.Print(b64)
+
+	// Output:
+	// NAHtAe0BE3E
+}
+```
+
 ## Documentation

 Documentation for this library is provided as Go docs at
@@ -51,7 +85,7 @@ simulate the `docker` daemon:
 export DOCKER_HOST=unix:///var/run/podman/podman.sock
 ```

-Since there's only one workflow, the simplest command to test it is:
+The simplest command to test it is:

 ```bash
 act
--- a/common.go
+++ b/common.go
@@ -4,70 +4,70 @@ import "fmt"

 // [IANA JOSE specification]: https://www.iana.org/assignments/jose/jose.xhtml#web-signature-encryption-algorithms

-// Ed25519 produces a varsig for EdDSA using Ed25519 curve.
+// Ed25519 produces a varsig for EdDSA using the Ed25519 curve.
 // This algorithm is defined in [IANA JOSE specification].
-func Ed25519(payloadEncoding PayloadEncoding, opts ...Option) (EdDSAVarsig, error) {
-	return NewEdDSAVarsig(CurveEd25519, HashSha2_512, payloadEncoding, opts...)
+func Ed25519(payloadEncoding PayloadEncoding) EdDSAVarsig {
+	return NewEdDSAVarsig(CurveEd25519, HashSha2_512, payloadEncoding)
 }

-// Ed448 produces a varsig for EdDSA using Ed448 curve.
+// Ed448 produces a varsig for EdDSA using the Ed448 curve.
 // This algorithm is defined in [IANA JOSE specification].
-func Ed448(payloadEncoding PayloadEncoding, opts ...Option) (EdDSAVarsig, error) {
-	return NewEdDSAVarsig(CurveEd448, HashShake_256, payloadEncoding, opts...)
+func Ed448(payloadEncoding PayloadEncoding) EdDSAVarsig {
+	return NewEdDSAVarsig(CurveEd448, HashShake_256, payloadEncoding)
 }

 // RS256 produces a varsig for RSASSA-PKCS1-v1_5 using SHA-256.
 // This algorithm is defined in [IANA JOSE specification].
-func RS256(keyLength uint64, payloadEncoding PayloadEncoding, opts ...Option) (RSAVarsig, error) {
-	return NewRSAVarsig(HashSha2_256, keyLength, payloadEncoding, opts...)
+func RS256(keyLength uint64, payloadEncoding PayloadEncoding) RSAVarsig {
+	return NewRSAVarsig(HashSha2_256, keyLength, payloadEncoding)
 }

 // RS384 produces a varsig for RSASSA-PKCS1-v1_5 using SHA-384.
 // This algorithm is defined in [IANA JOSE specification].
-func RS384(keyLength uint64, payloadEncoding PayloadEncoding, opts ...Option) (RSAVarsig, error) {
-	return NewRSAVarsig(HashSha2_384, keyLength, payloadEncoding, opts...)
+func RS384(keyLength uint64, payloadEncoding PayloadEncoding) RSAVarsig {
+	return NewRSAVarsig(HashSha2_384, keyLength, payloadEncoding)
 }

 // RS512 produces a varsig for RSASSA-PKCS1-v1_5 using SHA-512.
 // This algorithm is defined in [IANA JOSE specification].
-func RS512(keyLength uint64, payloadEncoding PayloadEncoding, opts ...Option) (RSAVarsig, error) {
-	return NewRSAVarsig(HashSha2_512, keyLength, payloadEncoding, opts...)
+func RS512(keyLength uint64, payloadEncoding PayloadEncoding) RSAVarsig {
+	return NewRSAVarsig(HashSha2_512, keyLength, payloadEncoding)
 }

 // ES256 produces a varsig for ECDSA using P-256 and SHA-256.
 // This algorithm is defined in [IANA JOSE specification].
-func ES256(payloadEncoding PayloadEncoding, opts ...Option) (ECDSAVarsig, error) {
-	return NewECDSAVarsig(CurveP256, HashSha2_256, payloadEncoding, opts...)
+func ES256(payloadEncoding PayloadEncoding) ECDSAVarsig {
+	return NewECDSAVarsig(CurveP256, HashSha2_256, payloadEncoding)
 }

 // ES256K produces a varsig for ECDSA using secp256k1 curve and SHA-256.
 // This algorithm is defined in [IANA JOSE specification].
-func ES256K(payloadEncoding PayloadEncoding, opts ...Option) (ECDSAVarsig, error) {
-	return NewECDSAVarsig(CurveSecp256k1, HashSha2_256, payloadEncoding, opts...)
+func ES256K(payloadEncoding PayloadEncoding) ECDSAVarsig {
+	return NewECDSAVarsig(CurveSecp256k1, HashSha2_256, payloadEncoding)
 }

 // ES384 produces a varsig for ECDSA using P-384 and SHA-384.
 // This algorithm is defined in [IANA JOSE specification].
-func ES384(payloadEncoding PayloadEncoding, opts ...Option) (ECDSAVarsig, error) {
-	return NewECDSAVarsig(CurveP384, HashSha2_384, payloadEncoding, opts...)
+func ES384(payloadEncoding PayloadEncoding) ECDSAVarsig {
+	return NewECDSAVarsig(CurveP384, HashSha2_384, payloadEncoding)
 }

 // ES512 produces a varsig for ECDSA using P-521 and SHA-512.
 // This algorithm is defined in [IANA JOSE specification].
-func ES512(payloadEncoding PayloadEncoding, opts ...Option) (ECDSAVarsig, error) {
-	return NewECDSAVarsig(CurveP521, HashSha2_512, payloadEncoding, opts...)
+func ES512(payloadEncoding PayloadEncoding) ECDSAVarsig {
+	return NewECDSAVarsig(CurveP521, HashSha2_512, payloadEncoding)
 }

 // EIP191 produces a varsig for ECDSA using the Secp256k1 curve, Keccak256 and encoded
 // with the "personal_sign" format defined by [EIP191].
 // payloadEncoding must be either PayloadEncodingEIP191Raw or PayloadEncodingEIP191Cbor.
 // [EIP191]: https://eips.ethereum.org/EIPS/eip-191
-func EIP191(payloadEncoding PayloadEncoding, opts ...Option) (ECDSAVarsig, error) {
+func EIP191(payloadEncoding PayloadEncoding) (ECDSAVarsig, error) {
 	switch payloadEncoding {
 	case PayloadEncodingEIP191Raw, PayloadEncodingEIP191Cbor:
 	default:
 		return ECDSAVarsig{}, fmt.Errorf("%w for EIP191: %v", ErrUnsupportedPayloadEncoding, payloadEncoding)
 	}

-	return NewECDSAVarsig(CurveSecp256k1, HashKeccak256, payloadEncoding, opts...)
+	return NewECDSAVarsig(CurveSecp256k1, HashKeccak_256, payloadEncoding), nil
 }
--- a/common_test.go
+++ b/common_test.go
@@ -19,47 +19,47 @@ func TestRoundTrip(t *testing.T) {
 		// Arbitrary use of presets
 		{
 			name:    "Ed25519",
-			varsig:  must(varsig.Ed25519(varsig.PayloadEncodingDAGCBOR)),
+			varsig:  varsig.Ed25519(varsig.PayloadEncodingDAGCBOR),
 			dataHex: "3401ed01ed011371",
 		},
 		{
 			name:    "Ed448",
-			varsig:  must(varsig.Ed448(varsig.PayloadEncodingDAGCBOR)),
+			varsig:  varsig.Ed448(varsig.PayloadEncodingDAGCBOR),
 			dataHex: "3401ed0183241971",
 		},
 		{
 			name:    "RS256",
-			varsig:  must(varsig.RS256(0x100, varsig.PayloadEncodingDAGCBOR)),
+			varsig:  varsig.RS256(0x100, varsig.PayloadEncodingDAGCBOR),
 			dataHex: "3401852412800271",
 		},
 		{
 			name:    "RS384",
-			varsig:  must(varsig.RS384(0x100, varsig.PayloadEncodingDAGCBOR)),
+			varsig:  varsig.RS384(0x100, varsig.PayloadEncodingDAGCBOR),
 			dataHex: "3401852420800271",
 		},
 		{
 			name:    "RS512",
-			varsig:  must(varsig.RS512(0x100, varsig.PayloadEncodingDAGCBOR)),
+			varsig:  varsig.RS512(0x100, varsig.PayloadEncodingDAGCBOR),
 			dataHex: "3401852413800271",
 		},
 		{
 			name:    "ES256",
-			varsig:  must(varsig.ES256(varsig.PayloadEncodingDAGCBOR)),
+			varsig:  varsig.ES256(varsig.PayloadEncodingDAGCBOR),
 			dataHex: "3401ec0180241271",
 		},
 		{
 			name:    "ES256K",
-			varsig:  must(varsig.ES256K(varsig.PayloadEncodingDAGCBOR)),
+			varsig:  varsig.ES256K(varsig.PayloadEncodingDAGCBOR),
 			dataHex: "3401ec01e7011271",
 		},
 		{
 			name:    "ES384",
-			varsig:  must(varsig.ES384(varsig.PayloadEncodingDAGCBOR)),
+			varsig:  varsig.ES384(varsig.PayloadEncodingDAGCBOR),
 			dataHex: "3401ec0181242071",
 		},
 		{
 			name:    "ES512",
-			varsig:  must(varsig.ES512(varsig.PayloadEncodingDAGCBOR)),
+			varsig:  varsig.ES512(varsig.PayloadEncodingDAGCBOR),
 			dataHex: "3401ec0182241371",
 		},
 		{
@@ -71,22 +71,22 @@ func TestRoundTrip(t *testing.T) {
 		// from https://github.com/hugomrdias/iso-repo/blob/main/packages/iso-ucan/test/varsig.test.js
 		{
 			name:      "RS256+RAW",
-			varsig:    must(varsig.RS256(256, varsig.PayloadEncodingVerbatim)),
+			varsig:    varsig.RS256(256, varsig.PayloadEncodingVerbatim),
 			dataBytes: []byte{52, 1, 133, 36, 18, 128, 2, 95},
 		},
 		{
 			name:      "ES256+RAW",
-			varsig:    must(varsig.ES256(varsig.PayloadEncodingVerbatim)),
+			varsig:    varsig.ES256(varsig.PayloadEncodingVerbatim),
 			dataBytes: []byte{52, 1, 236, 1, 128, 36, 18, 95},
 		},
 		{
 			name:      "ES512+RAW",
-			varsig:    must(varsig.ES512(varsig.PayloadEncodingVerbatim)),
+			varsig:    varsig.ES512(varsig.PayloadEncodingVerbatim),
 			dataBytes: []byte{52, 1, 236, 1, 130, 36, 19, 95},
 		},
 		{
 			name:      "ES256K+RAW",
-			varsig:    must(varsig.ES256K(varsig.PayloadEncodingVerbatim)),
+			varsig:    varsig.ES256K(varsig.PayloadEncodingVerbatim),
 			dataBytes: []byte{52, 1, 236, 1, 231, 1, 18, 95},
 		},
 		{
@@ -115,9 +115,8 @@ func TestRoundTrip(t *testing.T) {
 			require.NoError(t, err)

 			require.Equal(t, tc.varsig.Version(), rt.Version())
-			require.Equal(t, tc.varsig.Discriminator(), rt.Discriminator())
+			require.Equal(t, tc.varsig.Algorithm(), rt.Algorithm())
 			require.Equal(t, tc.varsig.PayloadEncoding(), rt.PayloadEncoding())
-			require.Equal(t, tc.varsig.Signature(), rt.Signature())

 			switch vs := tc.varsig.(type) {
 			case varsig.EdDSAVarsig:
--- a/constant.go
+++ b/constant.go
@@ -37,8 +37,14 @@ const (

 	HashShake_256 = Hash(0x19)

-	HashKeccak256 = Hash(0x1b)
-	HashKeccak512 = Hash(0x1d)
+	HashKeccak_256 = Hash(0x1b)
+	HashKeccak_512 = Hash(0x1d)
+
+	// You should likely not use those:
+	HashRipemd_160 = Hash(0x1053)
+	HashMd4        = Hash(0xd4)
+	HashMd5        = Hash(0xd5)
+	HashSha1       = Hash(0x11)
 )

 // DecodeHashAlgorithm reads and validates the expected hash algorithm
@@ -67,8 +73,12 @@ func DecodeHashAlgorithm(r BytesReader) (Hash, error) {
 		HashBlake2b_384,
 		HashBlake2b_512,
 		HashShake_256,
-		HashKeccak256,
-		HashKeccak512:
+		HashKeccak_256,
+		HashKeccak_512,
+		HashRipemd_160,
+		HashMd4,
+		HashMd5,
+		HashSha1:
 		return h, nil
 	default:
 		return HashUnspecified, fmt.Errorf("%w: %x", ErrUnknownHash, h)
@@ -82,7 +92,6 @@ type PayloadEncoding int

 // Constant values that allow Varsig implementations to specify how the
 // payload content is encoded before being hashed.
-// In varsig >= v1, only canonical encoding is allowed.
 const (
 	PayloadEncodingUnspecified = PayloadEncoding(iota)
 	PayloadEncodingVerbatim
@@ -105,67 +114,34 @@ const (

 // DecodePayloadEncoding reads and validates the expected canonical payload
 // encoding of the data to be signed.
-func DecodePayloadEncoding(r BytesReader, vers Version) (PayloadEncoding, error) {
+func DecodePayloadEncoding(r BytesReader) (PayloadEncoding, error) {
 	seg1, err := binary.ReadUvarint(r)
 	if err != nil {
 		return PayloadEncodingUnspecified, fmt.Errorf("%w: %w", ErrUnsupportedPayloadEncoding, err)
 	}

-	switch vers {
-	case Version0:
-		switch seg1 {
-		case encodingSegmentVerbatim:
-			return PayloadEncodingVerbatim, nil
-		case encodingSegmentDAGPB:
-			return PayloadEncodingDAGPB, nil
-		case encodingSegmentDAGCBOR:
-			return PayloadEncodingDAGCBOR, nil
-		case encodingSegmentDAGJSON:
-			return PayloadEncodingDAGJSON, nil
-		case encodingSegmentEIP191:
-			seg2, err := binary.ReadUvarint(r)
-			if err != nil {
-				return PayloadEncodingUnspecified, fmt.Errorf("%w: incomplete EIP191 encoding: %w", ErrUnsupportedPayloadEncoding, err)
-			}
-			switch seg2 {
-			case encodingSegmentVerbatim:
-				return PayloadEncodingEIP191Raw, nil
-			case encodingSegmentDAGCBOR:
-				return PayloadEncodingEIP191Cbor, nil
-			default:
-				return PayloadEncodingUnspecified, fmt.Errorf("%w: version=%d, encoding=%x+%x", ErrUnsupportedPayloadEncoding, vers, seg1, seg2)
-			}
-		case encodingSegmentJWT:
-			return PayloadEncodingJWT, nil
-		default:
-			return PayloadEncodingUnspecified, fmt.Errorf("%w: version=%d, encoding=%x", ErrUnsupportedPayloadEncoding, vers, seg1)
+	switch seg1 {
+	case encodingSegmentVerbatim:
+		return PayloadEncodingVerbatim, nil
+	case encodingSegmentDAGCBOR:
+		return PayloadEncodingDAGCBOR, nil
+	case encodingSegmentDAGJSON:
+		return PayloadEncodingDAGJSON, nil
+	case encodingSegmentEIP191:
+		seg2, err := binary.ReadUvarint(r)
+		if err != nil {
+			return PayloadEncodingUnspecified, fmt.Errorf("%w: incomplete EIP191 encoding: %w", ErrUnsupportedPayloadEncoding, err)
 		}
-	case Version1:
-		switch seg1 {
+		switch seg2 {
 		case encodingSegmentVerbatim:
-			return PayloadEncodingVerbatim, nil
+			return PayloadEncodingEIP191Raw, nil
 		case encodingSegmentDAGCBOR:
-			return PayloadEncodingDAGCBOR, nil
-		case encodingSegmentDAGJSON:
-			return PayloadEncodingDAGJSON, nil
-		case encodingSegmentEIP191:
-			seg2, err := binary.ReadUvarint(r)
-			if err != nil {
-				return PayloadEncodingUnspecified, fmt.Errorf("%w: incomplete EIP191 encoding: %w", ErrUnsupportedPayloadEncoding, err)
-			}
-			switch seg2 {
-			case encodingSegmentVerbatim:
-				return PayloadEncodingEIP191Raw, nil
-			case encodingSegmentDAGCBOR:
-				return PayloadEncodingEIP191Cbor, nil
-			default:
-				return PayloadEncodingUnspecified, fmt.Errorf("%w: version=%d, encoding=%x+%x", ErrUnsupportedPayloadEncoding, vers, seg1, seg2)
-			}
+			return PayloadEncodingEIP191Cbor, nil
 		default:
-			return PayloadEncodingUnspecified, fmt.Errorf("%w: version=%d, encoding=%x", ErrUnsupportedPayloadEncoding, vers, seg1)
+			return PayloadEncodingUnspecified, fmt.Errorf("%w: encoding=%x+%x", ErrUnsupportedPayloadEncoding, seg1, seg2)
 		}
 	default:
-		return 0, ErrUnsupportedVersion
+		return PayloadEncodingUnspecified, fmt.Errorf("%w: encoding=%x", ErrUnsupportedPayloadEncoding, seg1)
 	}
 }

@@ -197,14 +173,14 @@ func EncodePayloadEncoding(enc PayloadEncoding) []byte {
 	return res
 }

-// Discriminator is (usually) the value representing the public key type of
+// Algorithm is (usually) the value representing the public key type of
 // the algorithm used to create the signature.
 //
 // There is no set list of constants here, nor is there a decode function
 // as the author of an implementation should include the constant with the
 // implementation, and the decoding is handled by the Handler, which uses
-// the Discriminator to choose the correct implementation.  Also note that
-// some of the Discriminator values for a specific implementation have
+// the Algorithm to choose the correct implementation.  Also note that
+// some of the Algorithm values for a specific implementation have
 // changed between varsig v0 and v1, so it's possible to have more than one
 // constant defined per implementation.
-type Discriminator uint64
+type Algorithm uint64
--- a/constant_test.go
+++ b/constant_test.go
@@ -53,18 +53,10 @@ func TestDecodePayloadEncoding(t *testing.T) {
 	t.Run("passes", func(t *testing.T) {
 		t.Parallel()

-		t.Run("v0", func(t *testing.T) {
-			t.Parallel()
-
-			payEnc, err := varsig.DecodePayloadEncoding(bytes.NewReader([]byte{0x5f}), varsig.Version1)
-			require.NoError(t, err)
-			require.Equal(t, varsig.PayloadEncodingVerbatim, payEnc)
-		})
-
 		t.Run("v1", func(t *testing.T) {
 			t.Parallel()

-			payEnc, err := varsig.DecodePayloadEncoding(bytes.NewReader([]byte{0x5f}), varsig.Version1)
+			payEnc, err := varsig.DecodePayloadEncoding(bytes.NewReader([]byte{0x5f}))
 			require.NoError(t, err)
 			require.Equal(t, varsig.PayloadEncodingVerbatim, payEnc)
 		})
@@ -76,27 +68,13 @@ func TestDecodePayloadEncoding(t *testing.T) {
 		tests := []struct {
 			name string
 			data []byte
-			vers varsig.Version
 			err  error
 		}{
 			{
-				name: "unsupported encoding - v0",
-				data: []byte{0x42}, // random
-				vers: varsig.Version0,
-				err:  varsig.ErrUnsupportedPayloadEncoding,
-			},
-			{
-				name: "unsupported encoding - v1",
+				name: "unsupported encoding",
 				data: []byte{0x6a, 0x77}, // JWT
-				vers: varsig.Version1,
 				err:  varsig.ErrUnsupportedPayloadEncoding,
 			},
-			{
-				name: "unsupported version",
-				data: []byte{0x5f}, // Verbatim
-				vers: 99,           // random
-				err:  varsig.ErrUnsupportedVersion,
-			},
 		}

 		for _, tt := range tests {
@@ -105,10 +83,8 @@ func TestDecodePayloadEncoding(t *testing.T) {
 				t.Parallel()

 				r := bytes.NewReader(tt.data)
-				_, err := varsig.DecodePayloadEncoding(r, tt.vers)
+				_, err := varsig.DecodePayloadEncoding(r)
 				require.ErrorIs(t, err, tt.err)
-				// t.Log(err)
-				// t.Fail()
 			})
 		}
 	})
@@ -118,6 +94,6 @@ func BenchmarkDecodePayloadEncoding(b *testing.B) {
 	b.ReportAllocs()
 	data := []byte{0x5f}
 	for i := 0; i < b.N; i++ {
-		_, _ = varsig.DecodePayloadEncoding(bytes.NewReader(data), varsig.Version1)
+		_, _ = varsig.DecodePayloadEncoding(bytes.NewReader(data))
 	}
 }
--- a/ecdsa.go
+++ b/ecdsa.go
@@ -5,8 +5,8 @@ import (
 	"fmt"
 )

-// DiscriminatorECDSA is the value specifying an ECDSA signature.
-const DiscriminatorECDSA = Discriminator(0xec)
+// AlgorithmECDSA is the value specifying an ECDSA signature.
+const AlgorithmECDSA = Algorithm(0xec)

 // ECDSACurve are values that specify which ECDSA curve is used when
 // generating the signature.
@@ -48,42 +48,15 @@ type ECDSAVarsig struct {

 // NewECDSAVarsig creates and validates an ECDSA varsig with the provided
 // curve, hash algorithm and payload encoding.
-func NewECDSAVarsig(curve ECDSACurve, hashAlgorithm Hash, payloadEncoding PayloadEncoding, opts ...Option) (ECDSAVarsig, error) {
-	options := newOptions(opts...)
-
-	var (
-		vers = Version1
-		disc = DiscriminatorECDSA
-		sig  []byte
-	)
-
-	if options.ForceVersion0() {
-		vers = Version0
-		disc = Discriminator(curve)
-		sig = options.Signature()
-	}
-
-	v := ECDSAVarsig{
+func NewECDSAVarsig(curve ECDSACurve, hashAlgorithm Hash, payloadEncoding PayloadEncoding) ECDSAVarsig {
+	return ECDSAVarsig{
 		varsig: varsig{
-			vers:   vers,
-			disc:   disc,
+			algo:   AlgorithmECDSA,
 			payEnc: payloadEncoding,
-			sig:    sig,
 		},
 		curve:   curve,
 		hashAlg: hashAlgorithm,
 	}
-
-	switch curve {
-	case CurveSecp256k1, CurveP256:
-		return validateSig(v, 64)
-	case CurveP384:
-		return validateSig(v, 96)
-	case CurveP521:
-		return validateSig(v, 132)
-	default:
-		return ECDSAVarsig{}, fmt.Errorf("%w: %x", ErrUnknownECDSACurve, curve)
-	}
 }

 // Curve returns the elliptic curve used to generate the ECDSA signature.
@@ -101,26 +74,17 @@ func (v ECDSAVarsig) Hash() Hash {
 func (v ECDSAVarsig) Encode() []byte {
 	buf := v.encode()

-	if v.vers != Version0 {
-		buf = binary.AppendUvarint(buf, uint64(v.curve))
-	}
-
+	buf = binary.AppendUvarint(buf, uint64(v.curve))
 	buf = binary.AppendUvarint(buf, uint64(v.hashAlg))
 	buf = append(buf, EncodePayloadEncoding(v.payEnc)...)
-	buf = append(buf, v.Signature()...)

 	return buf
 }

-func decodeECDSA(r BytesReader, vers Version, disc Discriminator) (Varsig, error) {
-	curve := ECDSACurve(disc)
-	if vers != Version0 {
-		var err error
-
-		curve, err = decodeECDSACurve(r)
-		if err != nil {
-			return nil, err
-		}
+func decodeECDSA(r BytesReader) (Varsig, error) {
+	curve, err := decodeECDSACurve(r)
+	if err != nil {
+		return nil, err
 	}

 	hashAlg, err := DecodeHashAlgorithm(r)
@@ -128,28 +92,10 @@ func decodeECDSA(r BytesReader, vers Version, disc Discriminator) (Varsig, error
 		return nil, err
 	}

-	v := ECDSAVarsig{
-		varsig: varsig{
-			vers: vers,
-			disc: disc,
-		},
-		curve:   curve,
-		hashAlg: hashAlg,
-	}
-
-	v.payEnc, v.sig, err = v.decodePayEncAndSig(r)
+	payEnc, err := DecodePayloadEncoding(r)
 	if err != nil {
 		return nil, err
 	}

-	switch curve {
-	case CurveSecp256k1, CurveP256:
-		return validateSig(v, 64)
-	case CurveP384:
-		return validateSig(v, 96)
-	case CurveP521:
-		return validateSig(v, 132)
-	default:
-		return ECDSAVarsig{}, fmt.Errorf("%w: %x", ErrUnknownECDSACurve, curve)
-	}
+	return NewECDSAVarsig(curve, hashAlg, payEnc), nil
 }
--- a/eddsa.go
+++ b/eddsa.go
@@ -1,13 +1,12 @@
 package varsig

 import (
-	"crypto/ed25519"
 	"encoding/binary"
 	"fmt"
 )

-// DiscriminatorEdDSA is the value specifying an EdDSA signature.
-const DiscriminatorEdDSA = Discriminator(0xed)
+// AlgorithmEdDSA is the value specifying an EdDSA signature.
+const AlgorithmEdDSA = Algorithm(0xed)

 // EdDSACurve are values that specify which Edwards curve is used when
 // generating the signature.
@@ -47,40 +46,15 @@ type EdDSAVarsig struct {

 // NewEdDSAVarsig creates and validates an EdDSA varsig with the provided
 // curve, hash algorithm and payload encoding.
-func NewEdDSAVarsig(curve EdDSACurve, hashAlgorithm Hash, payloadEncoding PayloadEncoding, opts ...Option) (EdDSAVarsig, error) {
-	options := newOptions(opts...)
-
-	var (
-		vers = Version1
-		disc = DiscriminatorEdDSA
-		sig  []byte
-	)
-
-	if options.ForceVersion0() {
-		vers = Version0
-		disc = Discriminator(curve)
-		sig = options.Signature()
-	}
-
-	v := EdDSAVarsig{
+func NewEdDSAVarsig(curve EdDSACurve, hashAlgorithm Hash, payloadEncoding PayloadEncoding) EdDSAVarsig {
+	return EdDSAVarsig{
 		varsig: varsig{
-			vers:   vers,
-			disc:   disc,
+			algo:   AlgorithmEdDSA,
 			payEnc: payloadEncoding,
-			sig:    sig,
 		},
 		curve:   curve,
 		hashAlg: hashAlgorithm,
 	}
-
-	switch curve {
-	case CurveEd25519:
-		return validateSig(v, ed25519.SignatureSize)
-	case CurveEd448:
-		return validateSig(v, 114)
-	default:
-		return EdDSAVarsig{}, fmt.Errorf("%w: %x", ErrUnknownEdDSACurve, curve)
-	}
 }

 // Curve returns the Edwards curve used to generate the EdDSA signature.
@@ -98,26 +72,17 @@ func (v EdDSAVarsig) Hash() Hash {
 func (v EdDSAVarsig) Encode() []byte {
 	buf := v.encode()

-	if v.vers != Version0 {
-		buf = binary.AppendUvarint(buf, uint64(v.curve))
-	}
-
+	buf = binary.AppendUvarint(buf, uint64(v.curve))
 	buf = binary.AppendUvarint(buf, uint64(v.hashAlg))
 	buf = append(buf, EncodePayloadEncoding(v.payEnc)...)
-	buf = append(buf, v.Signature()...)

 	return buf
 }

-func decodeEdDSA(r BytesReader, vers Version, disc Discriminator) (Varsig, error) {
-	curve := EdDSACurve(disc)
-	if vers != Version0 {
-		var err error
-
-		curve, err = decodeEdDSACurve(r)
-		if err != nil {
-			return nil, err
-		}
+func decodeEdDSA(r BytesReader) (Varsig, error) {
+	curve, err := decodeEdDSACurve(r)
+	if err != nil {
+		return nil, err
 	}

 	hashAlg, err := DecodeHashAlgorithm(r)
@@ -125,26 +90,10 @@ func decodeEdDSA(r BytesReader, vers Version, disc Discriminator) (Varsig, error
 		return nil, err
 	}

-	v := EdDSAVarsig{
-		varsig: varsig{
-			vers: vers,
-			disc: disc,
-		},
-		curve:   curve,
-		hashAlg: hashAlg,
-	}
-
-	v.payEnc, v.sig, err = v.decodePayEncAndSig(r)
+	payEnc, err := DecodePayloadEncoding(r)
 	if err != nil {
 		return nil, err
 	}

-	switch curve {
-	case CurveEd25519:
-		return validateSig(v, ed25519.SignatureSize)
-	case CurveEd448:
-		return validateSig(v, 114)
-	default:
-		return EdDSAVarsig{}, fmt.Errorf("%w: %x", ErrUnknownEdDSACurve, curve)
-	}
+	return NewEdDSAVarsig(curve, hashAlg, payEnc), nil
 }
--- a/eddsa_test.go
+++ b/eddsa_test.go
@@ -2,7 +2,6 @@ package varsig_test

 import (
 	"encoding/base64"
-	"encoding/hex"
 	"testing"

 	"github.com/stretchr/testify/assert"
@@ -11,53 +10,6 @@ import (
 	"github.com/ucan-wg/go-varsig"
 )

-func TestDecodeEd25519(t *testing.T) {
-	t.Parallel()
-
-	t.Run("passes - section 3 example - v0", func(t *testing.T) {
-		// Original:  34ed01    1371ae3784f03f9ee1163382fa6efa73b0c31ecf58c899c836709303ba4621d1e6df20e09aaa568914290b7ea124f5b38e70b9b69c7de0d216880eac885edd41c302
-		// Corrected: 34ed011371ae3784f03f9ee1163382fa6efa73b0c31ecf58c899c836709303ba4621d1e6df20e09aaa568914290b7ea124f5b38e70b9b69c7de0d216880eac885edd41c302")
-
-		hdr, err := hex.DecodeString("34ed011371")
-		require.NoError(t, err)
-
-		sig, err := hex.DecodeString("ae3784f03f9ee1163382fa6efa73b0c31ecf58c899c836709303ba4621d1e6df20e09aaa568914290b7ea124f5b38e70b9b69c7de0d216880eac885edd41c302")
-		require.NoError(t, err)
-		require.Len(t, sig, 64)
-
-		t.Run("Decode", func(t *testing.T) {
-			t.Parallel()
-
-			v, err := varsig.Decode(append(hdr, sig...))
-			require.NoError(t, err)
-			require.NotNil(t, v)
-			assert.Equal(t, varsig.Version0, v.Version())
-			assert.Equal(t, varsig.DiscriminatorEdDSA, v.Discriminator())
-			assert.Equal(t, varsig.PayloadEncodingDAGCBOR, v.PayloadEncoding())
-			assert.Len(t, v.Signature(), 64)
-
-			impl, ok := v.(varsig.EdDSAVarsig)
-			require.True(t, ok)
-			assert.Equal(t, varsig.CurveEd25519, impl.Curve())
-			assert.Equal(t, varsig.HashSha2_512, impl.Hash())
-		})
-
-		t.Run("Encode", func(t *testing.T) {
-			t.Parallel()
-
-			v, err := varsig.NewEdDSAVarsig(
-				varsig.CurveEd25519,
-				varsig.HashSha2_512,
-				varsig.PayloadEncodingDAGCBOR,
-				varsig.WithForceVersion0(sig),
-			)
-			require.NoError(t, err)
-			require.NotNil(t, v)
-			assert.Equal(t, append(hdr, sig...), v.Encode())
-		})
-	})
-}
-
 func TestUCANExampleV1(t *testing.T) {
 	t.Parallel()

@@ -77,22 +29,20 @@ func TestUCANExampleV1(t *testing.T) {
 		require.True(t, ok)

 		assert.Equal(t, varsig.Version1, ed25519V.Version())
-		assert.Equal(t, varsig.DiscriminatorEdDSA, ed25519V.Discriminator())
+		assert.Equal(t, varsig.AlgorithmEdDSA, ed25519V.Algorithm())
 		assert.Equal(t, varsig.CurveEd25519, ed25519V.Curve())
 		assert.Equal(t, varsig.HashSha2_512, ed25519V.Hash())
 		assert.Equal(t, varsig.PayloadEncodingDAGCBOR, ed25519V.PayloadEncoding())
-		assert.Len(t, ed25519V.Signature(), 0)
 	})

 	t.Run("Encode", func(t *testing.T) {
 		t.Parallel()

-		edDSAVarsig, err := varsig.NewEdDSAVarsig(
+		edDSAVarsig := varsig.NewEdDSAVarsig(
 			varsig.CurveEd25519,
 			varsig.HashSha2_512,
 			varsig.PayloadEncodingDAGCBOR,
 		)
-		require.NoError(t, err)

 		assert.Equal(t, example, edDSAVarsig.Encode())
 		t.Log(base64.RawStdEncoding.EncodeToString(edDSAVarsig.Encode()))
--- a/error.go
+++ b/error.go
@@ -2,25 +2,11 @@ package varsig

 import "errors"

-// ErrMissingSignature is returned when a varsig v0 is parsed and does
-// not contain the expected signature bytes.  This is expected in some
-// intermediate cases, such as the UCAN v1 specification.
-var ErrMissingSignature = errors.New("missing signature expected in varsig v0")
-
 // ErrNotYetImplemented is returned when a function is currently under
 // construction.  For released versions of this library, this error should
 // never occur.
 var ErrNotYetImplemented = errors.New("not yet implemented")

-// ErrUnexpectedSignaturePresent is returned when a signature is present
-// in a varsig >= v1.
-var ErrUnexpectedSignaturePresent = errors.New("unexpected signature present in varsig >= v1")
-
-// ErrUnexpectedSignatureSize is returned when the length of the decoded
-// signature doesn't match the expected signature length as defined by the
-// signing algorithm or sent via a Varsig field.
-var ErrUnexpectedSignatureSize = errors.New("unexpected signature size in varsig v0")
-
 // ErrUnknownHash is returned when an unexpected value is provided
 // while decoding the hashing algorithm.
 var ErrUnknownHash = errors.New("unknown hash algorithm")
@@ -30,9 +16,9 @@ var ErrUnknownHash = errors.New("unknown hash algorithm")
 // for this field may vary based on the varsig version.
 var ErrUnsupportedPayloadEncoding = errors.New("unsupported payload encoding")

-// ErrUnknownDiscriminator is returned when the Registry doesn't have a
+// ErrUnknownAlgorithm is returned when the Registry doesn't have a
 // parsing function for the decoded signing algorithm.
-var ErrUnknownDiscriminator = errors.New("unknown signing algorithm")
+var ErrUnknownAlgorithm = errors.New("unknown signing algorithm")

 // ErrUnknownEdDSACurve is returned when the decoded uvarint isn't either
 // CurveEd25519 or CurveEd448.
--- a/option.go
+++ b/option.go
@@ -1,45 +0,0 @@
-package varsig
-
-// Options define customization when creating a new Varsig.
-type Options struct {
-	forceVersion0 bool
-	signature     []byte
-}
-
-func newOptions(opts ...Option) *Options {
-	o := &Options{}
-
-	for _, opt := range opts {
-		opt(o)
-	}
-
-	return o
-}
-
-// ForceVersion0 returns a boolean indicating that a Varsig < v1 should
-// be created (which means the encoded Varsig won't have a version field
-// and might contain the signature bytes as the last field.)
-func (o *Options) ForceVersion0() bool {
-	return o.forceVersion0
-}
-
-// Signature returns the optional signature bytes when creating a Varsig
-// < v1.
-func (o *Options) Signature() []byte {
-	return o.signature
-}
-
-// Option is a function that alters the default behavior of constructors
-// that produce implementations of the Varsig type.
-type Option func(*Options)
-
-// WithForceVersion0 indicates that a Varsig < v1 should be produced. If
-// the signature is a) not nil, b) not empty and c) the correct length
-// based on the signing algorithm or signing key, the signature's bytes
-// will be appended to the encoded Varsig.
-func WithForceVersion0(signature []byte) Option {
-	return func(o *Options) {
-		o.forceVersion0 = true
-		o.signature = signature
-	}
-}
--- a/registry.go
+++ b/registry.go
@@ -18,19 +18,19 @@ const (

 // DecodeFunc is a function that parses the varsig representing a specific
 // signing algorithm.
-type DecodeFunc func(BytesReader, Version, Discriminator) (Varsig, error)
+type DecodeFunc func(BytesReader) (Varsig, error)

 // Registry contains a mapping between known signing algorithms and
 // functions that can parse varsigs for that signing algorithm.
-type Registry map[Discriminator]DecodeFunc
+type Registry map[Algorithm]DecodeFunc

 // DefaultRegistry provides a Registry containing the mappings for the
 // signing algorithms which have an implementation within this library.
 func DefaultRegistry() Registry {
-	return map[Discriminator]DecodeFunc{
-		DiscriminatorRSA:   decodeRSA,
-		DiscriminatorEdDSA: decodeEdDSA,
-		DiscriminatorECDSA: decodeECDSA,
+	return map[Algorithm]DecodeFunc{
+		AlgorithmRSA:   decodeRSA,
+		AlgorithmEdDSA: decodeEdDSA,
+		AlgorithmECDSA: decodeECDSA,
 	}
 }

@@ -41,7 +41,7 @@ func NewRegistry() Registry {

 // Register allows new mappings between a signing algorithm and its parsing
 // function to the Registry.
-func (rs Registry) Register(alg Discriminator, decodeFunc DecodeFunc) {
+func (rs Registry) Register(alg Algorithm, decodeFunc DecodeFunc) {
 	rs[alg] = decodeFunc
 }

@@ -63,20 +63,24 @@ func (rs Registry) DecodeStream(r BytesReader) (Varsig, error) {
 		return nil, fmt.Errorf("%w: expected %d, got %d", ErrBadPrefix, Prefix, pre)
 	}

-	vers, disc, err := rs.decodeVersAnddisc(r)
+	vers, algo, err := rs.decodeVersAndAlgo(r)
 	if err != nil {
 		return nil, err
 	}

-	decodeFunc, ok := rs[Discriminator(disc)]
-	if !ok {
-		return nil, fmt.Errorf("%w: %x", ErrUnknownDiscriminator, disc)
+	if vers != Version1 {
+		return nil, fmt.Errorf("%w: %d", ErrUnsupportedVersion, vers)
 	}

-	return decodeFunc(r, vers, disc)
+	decodeFunc, ok := rs[Algorithm(algo)]
+	if !ok {
+		return nil, fmt.Errorf("%w: %x", ErrUnknownAlgorithm, algo)
+	}
+
+	return decodeFunc(r)
 }

-func (rs Registry) decodeVersAnddisc(r BytesReader) (Version, Discriminator, error) {
+func (rs Registry) decodeVersAndAlgo(r BytesReader) (Version, Algorithm, error) {
 	vers, err := binary.ReadUvarint(r)
 	if err != nil {
 		return Version(vers), 0, err
@@ -87,10 +91,10 @@ func (rs Registry) decodeVersAnddisc(r BytesReader) (Version, Discriminator, err
 	}

 	if vers >= 64 {
-		return 0, Discriminator(vers), nil
+		return 0, Algorithm(vers), nil
 	}

-	disc, err := binary.ReadUvarint(r)
+	algo, err := binary.ReadUvarint(r)

-	return Version(vers), Discriminator(disc), err
+	return Version(vers), Algorithm(algo), err
 }
--- a/registry_test.go
+++ b/registry_test.go
@@ -12,25 +12,7 @@ import (
 )

 func TestRegistry_Decode(t *testing.T) {
-	t.Parallel()
-
-	t.Run("passes - v0", func(t *testing.T) {
-		t.Parallel()
-
-		data, err := hex.DecodeString("348120")
-		require.NoError(t, err)
-
-		reg := testRegistry(t)
-
-		vs, err := reg.DecodeStream(bytes.NewReader(data))
-		require.NoError(t, err)
-		assert.Equal(t, varsig.Version0, vs.Version())
-		assert.Equal(t, testDiscriminator1, vs.Discriminator())
-	})
-
 	t.Run("passes - v1", func(t *testing.T) {
-		t.Parallel()
-
 		data, err := hex.DecodeString("34018120")
 		require.NoError(t, err)

@@ -39,63 +21,54 @@ func TestRegistry_Decode(t *testing.T) {
 		vs, err := reg.DecodeStream(bytes.NewReader(data))
 		require.NoError(t, err)
 		assert.Equal(t, varsig.Version1, vs.Version())
-		assert.Equal(t, testDiscriminator1, vs.Discriminator())
+		assert.Equal(t, testAlgorithm1, vs.Algorithm())
 	})
 }

 const (
-	testDiscriminator0 varsig.Discriminator = 0x1000
-	testDiscriminator1 varsig.Discriminator = 0x1001
+	testAlgorithm0 varsig.Algorithm = 0x1000
+	testAlgorithm1 varsig.Algorithm = 0x1001
 )

 func testRegistry(t *testing.T) varsig.Registry {
 	t.Helper()

 	reg := varsig.NewRegistry()
-	reg.Register(testDiscriminator0, testDecodeFunc(t))
-	reg.Register(testDiscriminator1, testDecodeFunc(t))
+	reg.Register(testAlgorithm0, testDecodeFunc(testAlgorithm0))
+	reg.Register(testAlgorithm1, testDecodeFunc(testAlgorithm1))

 	return reg
 }

-func testDecodeFunc(t *testing.T) varsig.DecodeFunc {
-	t.Helper()
-
-	return func(r varsig.BytesReader, vers varsig.Version, disc varsig.Discriminator) (varsig.Varsig, error) {
-		v := &testVarsig{
-			vers: vers,
-			disc: disc,
-		}
-
-		return v, nil
+func testDecodeFunc(algo varsig.Algorithm) varsig.DecodeFunc {
+	return func(r varsig.BytesReader) (varsig.Varsig, error) {
+		return &testVarsig{algo: algo}, nil
 	}
 }

 var _ varsig.Varsig = testVarsig{}

 type testVarsig struct {
-	vers   varsig.Version
-	disc   varsig.Discriminator
+	algo   varsig.Algorithm
 	payEnc varsig.PayloadEncoding
-	sig    []byte
 }

 func (v testVarsig) Version() varsig.Version {
-	return v.vers
+	return varsig.Version1
 }

-func (v testVarsig) Discriminator() varsig.Discriminator {
-	return v.disc
+func (v testVarsig) Algorithm() varsig.Algorithm {
+	return v.algo
+}
+
+func (v testVarsig) Hash() varsig.Hash {
+	return varsig.HashUnspecified
 }

 func (v testVarsig) PayloadEncoding() varsig.PayloadEncoding {
 	return v.payEnc
 }

-func (v testVarsig) Signature() []byte {
-	return v.sig
-}
-
 func (v testVarsig) Encode() []byte {
 	return nil
 }
--- a/rsa.go
+++ b/rsa.go
@@ -4,8 +4,8 @@ import (
 	"encoding/binary"
 )

-// DiscriminatorRSA is the value specifying an RSA signature.
-const DiscriminatorRSA = Discriminator(0x1205)
+// AlgorithmRSA is the value specifying an RSA signature.
+const AlgorithmRSA = Algorithm(0x1205)

 var _ Varsig = RSAVarsig{}

@@ -14,45 +14,29 @@ var _ Varsig = RSAVarsig{}
 type RSAVarsig struct {
 	varsig
 	hashAlg Hash
-	sigLen  uint64
+	keyLen  uint64
 }

 // NewRSAVarsig creates and validates an RSA varsig with the provided
 // hash algorithm, key length and payload encoding.
-func NewRSAVarsig(hashAlgorithm Hash, keyLength uint64, payloadEncoding PayloadEncoding, opts ...Option) (RSAVarsig, error) {
-	options := newOptions(opts...)
-
-	var (
-		vers = Version1
-		sig  []byte
-	)
-
-	if options.ForceVersion0() {
-		vers = Version0
-		sig = options.Signature()
-	}
-
-	v := RSAVarsig{
+func NewRSAVarsig(hashAlgorithm Hash, keyLen uint64, payloadEncoding PayloadEncoding) RSAVarsig {
+	return RSAVarsig{
 		varsig: varsig{
-			vers:   vers,
-			disc:   DiscriminatorRSA,
+			algo:   AlgorithmRSA,
 			payEnc: payloadEncoding,
-			sig:    sig,
 		},
 		hashAlg: hashAlgorithm,
-		sigLen:  keyLength,
+		keyLen:  keyLen,
 	}
-
-	return validateSig(v, v.sigLen)
 }

 // Encode returns the encoded byte format of the RSAVarsig.
 func (v RSAVarsig) Encode() []byte {
 	buf := v.encode()
+
 	buf = binary.AppendUvarint(buf, uint64(v.hashAlg))
-	buf = binary.AppendUvarint(buf, v.sigLen)
+	buf = binary.AppendUvarint(buf, v.keyLen)
 	buf = append(buf, EncodePayloadEncoding(v.payEnc)...)
-	buf = append(buf, v.Signature()...)

 	return buf
 }
@@ -66,33 +50,24 @@ func (v RSAVarsig) Hash() Hash {
 // KeyLength returns the length of the RSA key used to sign the payload
 // content.
 func (v RSAVarsig) KeyLength() uint64 {
-	return v.sigLen
+	return v.keyLen
 }

-func decodeRSA(r BytesReader, vers Version, disc Discriminator) (Varsig, error) {
+func decodeRSA(r BytesReader) (Varsig, error) {
 	hashAlg, err := DecodeHashAlgorithm(r)
 	if err != nil {
 		return nil, err
 	}

-	sigLen, err := binary.ReadUvarint(r)
+	keyLen, err := binary.ReadUvarint(r)
 	if err != nil {
 		return nil, err
 	}

-	vs := RSAVarsig{
-		varsig: varsig{
-			vers: vers,
-			disc: disc,
-		},
-		hashAlg: hashAlg,
-		sigLen:  sigLen,
-	}
-
-	vs.payEnc, vs.sig, err = vs.decodePayEncAndSig(r)
+	payEnc, err := DecodePayloadEncoding(r)
 	if err != nil {
 		return nil, err
 	}

-	return validateSig(vs, vs.sigLen)
+	return NewRSAVarsig(hashAlg, keyLen, payEnc), nil
 }
--- a/rsa_test.go
+++ b/rsa_test.go
@@ -4,7 +4,6 @@ import (
 	"encoding/base64"
 	"testing"

-	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"

 	"github.com/ucan-wg/go-varsig"
@@ -29,68 +28,23 @@ func TestRSAVarsig(t *testing.T) {
 		rsaVs, ok := vs.(varsig.RSAVarsig)
 		require.True(t, ok)

-		assert.Equal(t, varsig.Version1, rsaVs.Version())
-		assert.Equal(t, varsig.DiscriminatorRSA, rsaVs.Discriminator())
-		assert.Equal(t, varsig.HashSha2_256, rsaVs.Hash())
-		assert.Equal(t, varsig.PayloadEncodingDAGCBOR, rsaVs.PayloadEncoding())
-		assert.Equal(t, uint64(keyLen), rsaVs.KeyLength())
-		assert.Len(t, rsaVs.Signature(), 0)
+		require.Equal(t, varsig.Version1, rsaVs.Version())
+		require.Equal(t, varsig.AlgorithmRSA, rsaVs.Algorithm())
+		require.Equal(t, varsig.HashSha2_256, rsaVs.Hash())
+		require.Equal(t, varsig.PayloadEncodingDAGCBOR, rsaVs.PayloadEncoding())
+		require.Equal(t, uint64(keyLen), rsaVs.KeyLength())
 	})

 	t.Run("Encode", func(t *testing.T) {
 		t.Parallel()

-		rsaVarsig, err := varsig.NewRSAVarsig(
+		rsaVarsig := varsig.NewRSAVarsig(
 			varsig.HashSha2_256,
 			keyLen,
 			varsig.PayloadEncodingDAGCBOR,
 		)
-		require.NoError(t, err)

-		assert.Equal(t, example, rsaVarsig.Encode())
+		require.Equal(t, example, rsaVarsig.Encode())
 		t.Log(base64.RawStdEncoding.EncodeToString(rsaVarsig.Encode()))
 	})
 }
-
-func TestUCANExampleV0(t *testing.T) {
-	t.Parallel()
-
-	const keyLen = 0x100
-
-	// This test is the value shown in the UCAN v1.0.0 example, which is
-	// an RSA varsig < v1 encoded as RS256 with a key length of 0x100
-	// bytes and DAG-CBOR payload encoding.
-	example, err := base64.RawStdEncoding.DecodeString("NIUkEoACcQ")
-	require.NoError(t, err)
-
-	t.Run("Decode", func(t *testing.T) {
-		t.Parallel()
-
-		vs, err := varsig.Decode(example)
-		require.ErrorIs(t, err, varsig.ErrMissingSignature)
-
-		rsaVs, ok := vs.(varsig.RSAVarsig)
-		require.True(t, ok)
-
-		assert.Equal(t, varsig.Version0, rsaVs.Version())
-		assert.Equal(t, varsig.DiscriminatorRSA, rsaVs.Discriminator())
-		assert.Equal(t, varsig.HashSha2_256, rsaVs.Hash())
-		assert.Equal(t, varsig.PayloadEncodingDAGCBOR, rsaVs.PayloadEncoding())
-		assert.Equal(t, uint64(keyLen), rsaVs.KeyLength())
-		assert.Len(t, rsaVs.Signature(), 0)
-	})
-
-	t.Run("Encode", func(t *testing.T) {
-		t.Parallel()
-
-		rsaVarsig, err := varsig.NewRSAVarsig(
-			varsig.HashSha2_256,
-			keyLen,
-			varsig.PayloadEncodingDAGCBOR,
-			varsig.WithForceVersion0([]byte{}),
-		)
-		require.ErrorIs(t, err, varsig.ErrMissingSignature)
-
-		assert.Equal(t, example, rsaVarsig.Encode())
-	})
-}
--- a/varsig.go
+++ b/varsig.go
@@ -20,7 +20,6 @@ package varsig

 import (
 	"encoding/binary"
-	"errors"
 	"io"
 )

@@ -30,17 +29,15 @@ type Varsig interface {
 	// Version returns the varsig's version field.
 	Version() Version

-	// Discriminator returns the algorithm used to produce the corresponding signature.
-	Discriminator() Discriminator
+	// Algorithm returns the algorithm used to produce the corresponding signature.
+	Algorithm() Algorithm
+
+	// Hash returns the hash used on the data before signature.
+	Hash() Hash

 	// PayloadEncoding returns the codec that was used to encode the signed data.
 	PayloadEncoding() PayloadEncoding

-	// Signature returns the cryptographic signature of the signed data.
-	// This value is never present in a varsig >= v1 and must either be a valid
-	// signature with the correct length or empty in varsig < v1.
-	Signature() []byte
-
 	// Encode returns the encoded byte format of the varsig.
 	Encode() []byte
 }
@@ -58,21 +55,19 @@ func DecodeStream(r BytesReader) (Varsig, error) {
 }

 type varsig struct {
-	vers   Version
-	disc   Discriminator
+	algo   Algorithm
 	payEnc PayloadEncoding
-	sig    []byte
 }

 // Version returns the varsig's version field.
 func (v varsig) Version() Version {
-	return v.vers
+	return Version1
 }

-// Discriminator returns the algorithm used to produce the corresponding
+// Algorithm returns the algorithm used to produce the corresponding
 // signature.
-func (v varsig) Discriminator() Discriminator {
-	return v.disc
+func (v varsig) Algorithm() Algorithm {
+	return v.algo
 }

 // PayloadEncoding returns the codec that was used to encode the signed
@@ -81,13 +76,6 @@ func (v varsig) PayloadEncoding() PayloadEncoding {
 	return v.payEnc
 }

-// Signature returns the cryptographic signature of the signed data. This
-// value is never present in a varsig >= v1 and must either be a valid
-// signature with the correct length or empty in varsig < v1.
-func (v varsig) Signature() []byte {
-	return v.sig
-}
-
 func (v varsig) encode() []byte {
 	// Pre-allocate to the maximum size to avoid re-allocating.
 	// I think the maximum is 10 bytes, but it's all the same for go to allocate 16 (due to the small
@@ -95,60 +83,12 @@ func (v varsig) encode() []byte {
 	buf := make([]byte, 0, 16)

 	buf = binary.AppendUvarint(buf, Prefix)
-
-	if v.Version() == Version1 {
-		buf = binary.AppendUvarint(buf, uint64(Version1))
-	}
-
-	buf = binary.AppendUvarint(buf, uint64(v.disc))
+	buf = binary.AppendUvarint(buf, uint64(Version1))
+	buf = binary.AppendUvarint(buf, uint64(v.algo))

 	return buf
 }

-func (v varsig) decodePayEncAndSig(r BytesReader) (PayloadEncoding, []byte, error) {
-	payEnc, err := DecodePayloadEncoding(r, v.Version())
-	if err != nil {
-		return 0, nil, err
-	}
-
-	var signature []byte
-	switch v.Version() {
-	case Version0:
-		signature, err = io.ReadAll(r)
-		if err != nil {
-			return 0, nil, err
-		}
-	case Version1:
-		_, err := r.ReadByte()
-		if err != nil && !errors.Is(err, io.EOF) {
-			return 0, nil, err
-		}
-		if err == nil {
-			return 0, nil, ErrUnexpectedSignaturePresent
-		}
-	default:
-		return 0, nil, ErrUnsupportedVersion
-	}
-
-	return payEnc, signature, nil
-}
-
-func validateSig[T Varsig](v T, expectedLength uint64) (T, error) {
-	if v.Version() == Version0 && len(v.Signature()) == 0 {
-		return v, ErrMissingSignature
-	}
-
-	if v.Version() == Version0 && uint64(len(v.Signature())) != expectedLength {
-		return *new(T), ErrUnexpectedSignatureSize
-	}
-
-	if v.Version() == Version1 && len(v.Signature()) != 0 {
-		return *new(T), ErrUnexpectedSignaturePresent
-	}
-
-	return v, nil
-}
-
 type BytesReader interface {
 	io.ByteReader
 	io.Reader
--- a/varsig_test.go
+++ b/varsig_test.go
@@ -1,7 +1,9 @@
 package varsig_test

 import (
+	"encoding/base64"
 	"encoding/hex"
+	"fmt"
 	"io"
 	"testing"

@@ -11,6 +13,39 @@ import (
 	"github.com/ucan-wg/go-varsig"
 )

+func ExampleDecode() {
+	example, err := base64.RawStdEncoding.DecodeString("NAHtAe0BE3E")
+	handleErr(err)
+
+	vs, err := varsig.Decode(example)
+	handleErr(err)
+
+	fmt.Printf("%T\n", vs)
+	fmt.Printf("Algorithm: %d\n", vs.Algorithm())
+	fmt.Printf("Hash: %d\n", vs.Hash())
+	fmt.Printf("PayloadEncoding: %d\n", vs.PayloadEncoding())
+
+	// Output:
+	// varsig.EdDSAVarsig
+	// Algorithm: 237
+	// Hash: 19
+	// PayloadEncoding: 3
+}
+
+func ExampleEncode() {
+	edDSAVarsig := varsig.NewEdDSAVarsig(
+		varsig.CurveEd25519,
+		varsig.HashSha2_512,
+		varsig.PayloadEncodingDAGCBOR,
+	)
+
+	b64 := base64.RawStdEncoding.EncodeToString(edDSAVarsig.Encode())
+	fmt.Print(b64)
+
+	// Output:
+	// NAHtAe0BE3E
+}
+
 func TestDecode(t *testing.T) {
 	t.Parallel()

@@ -58,17 +93,6 @@ func TestDecode(t *testing.T) {
 		assert.Nil(t, vs)
 	})

-	t.Run("fails - unknown signature algorithm - v0", func(t *testing.T) {
-		t.Parallel()
-
-		data, err := hex.DecodeString("3464")
-		require.NoError(t, err)
-
-		vs, err := varsig.Decode(data)
-		require.ErrorIs(t, err, varsig.ErrUnknownDiscriminator)
-		assert.Nil(t, vs)
-	})
-
 	t.Run("fails - unknown signature algorithm - v1", func(t *testing.T) {
 		t.Parallel()

@@ -76,7 +100,7 @@ func TestDecode(t *testing.T) {
 		require.NoError(t, err)

 		vs, err := varsig.Decode(data)
-		require.ErrorIs(t, err, varsig.ErrUnknownDiscriminator)
+		require.ErrorIs(t, err, varsig.ErrUnknownAlgorithm)
 		assert.Nil(t, vs)
 	})

@@ -87,7 +111,6 @@ func TestDecode(t *testing.T) {
 		rsaHex    = "8524"
 		sha256Hex = "12"
 		keyLen    = "8002"
-		rsaBaseV0 = "34" + rsaHex + sha256Hex + keyLen
 		rsaBaseV1 = "3401" + rsaHex + sha256Hex + keyLen
 	)

@@ -123,36 +146,10 @@ func TestDecode(t *testing.T) {
 		require.ErrorIs(t, err, varsig.ErrUnsupportedPayloadEncoding)
 		assert.Nil(t, vs)
 	})
-
-	t.Run("fails - unexpected signature length - v0", func(t *testing.T) {
-		t.Parallel()
-
-		data, err := hex.DecodeString(rsaBaseV0 + "5f" + "42") // 0x42 is only a single byte - 256 bytes are expected
-		require.NoError(t, err)
-
-		vs, err := varsig.Decode(data)
-		require.ErrorIs(t, err, varsig.ErrUnexpectedSignatureSize)
-		assert.Zero(t, vs)
-	})
-
-	t.Run("fails - unexpected signature present - v1", func(t *testing.T) {
-		t.Parallel()
-
-		data, err := hex.DecodeString(rsaBaseV1 + "5f" + "42") // 0x42 is only a single byte - 256 bytes are expected
-		require.NoError(t, err)
-
-		vs, err := varsig.Decode(data)
-		require.ErrorIs(t, err, varsig.ErrUnexpectedSignaturePresent)
-		assert.Nil(t, vs)
-	})
-
-	t.Run("passes with error - v0", func(t *testing.T) {
-		t.Parallel()
-		data, err := hex.DecodeString(rsaBaseV0 + "5f")
-		require.NoError(t, err)
-
-		vs, err := varsig.Decode(data)
-		require.ErrorIs(t, err, varsig.ErrMissingSignature)
-		assert.NotNil(t, vs) // varsig is still returned with just "header"
-	})
+}
+
+func handleErr(err error) {
+	if err != nil {
+		panic(err)
+	}
 }
Author	SHA1	Message	Date
Michael Muré	2c902a565e	update the license files to make go do happy	2025-08-05 15:46:53 +02:00
Michael Muré	58ebd20b04	feat: rename Discriminant to Algorithm	2025-08-05 15:41:30 +02:00
Michael Muré	68e0d91f64	feat(doc): add some basic examples	2025-08-05 15:36:36 +02:00
Michael Muré	8c8da51656	Expose the hash on all varsig	2025-07-29 15:22:15 +02:00
Michael Muré	af0845c832	Remove support for varsig v0	2025-07-28 20:41:02 +02:00