86 lines
2.1 KiB
Go
86 lines
2.1 KiB
Go
package jwt
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import (
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"errors"
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"crypto"
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"crypto/ed25519"
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"crypto/rand"
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)
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var (
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ErrEd25519Verification = errors.New("ed25519: verification error")
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)
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// SigningMethodEd25519 implements the EdDSA family.
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// Expects ed25519.PrivateKey for signing and ed25519.PublicKey for verification
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type SigningMethodEd25519 struct{}
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// Specific instance for EdDSA
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var (
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SigningMethodEdDSA *SigningMethodEd25519
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)
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func init() {
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SigningMethodEdDSA = &SigningMethodEd25519{}
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RegisterSigningMethod(SigningMethodEdDSA.Alg(), func() SigningMethod {
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return SigningMethodEdDSA
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})
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}
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func (m *SigningMethodEd25519) Alg() string {
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return "EdDSA"
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}
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// Verify implements token verification for the SigningMethod.
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// For this verify method, key must be an ed25519.PublicKey
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func (m *SigningMethodEd25519) Verify(signingString, signature string, key interface{}) error {
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var err error
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var ed25519Key ed25519.PublicKey
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var ok bool
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if ed25519Key, ok = key.(ed25519.PublicKey); !ok {
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return ErrInvalidKeyType
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}
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if len(ed25519Key) != ed25519.PublicKeySize {
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return ErrInvalidKey
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}
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// Decode the signature
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var sig []byte
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if sig, err = DecodeSegment(signature); err != nil {
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return err
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}
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// Verify the signature
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if !ed25519.Verify(ed25519Key, []byte(signingString), sig) {
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return ErrEd25519Verification
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}
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return nil
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}
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// Sign implements token signing for the SigningMethod.
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// For this signing method, key must be an ed25519.PrivateKey
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func (m *SigningMethodEd25519) Sign(signingString string, key interface{}) (string, error) {
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var ed25519Key crypto.Signer
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var ok bool
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if ed25519Key, ok = key.(crypto.Signer); !ok {
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return "", ErrInvalidKeyType
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}
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if _, ok := ed25519Key.Public().(ed25519.PublicKey); !ok {
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return "", ErrInvalidKey
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}
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// Sign the string and return the encoded result
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// ed25519 performs a two-pass hash as part of its algorithm. Therefore, we need to pass a non-prehashed message into the Sign function, as indicated by crypto.Hash(0)
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sig, err := ed25519Key.Sign(rand.Reader, []byte(signingString), crypto.Hash(0))
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if err != nil {
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return "", err
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}
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return EncodeSegment(sig), nil
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}
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