ory-am/hydra

// Copyright © 2022 Ory Corp
// SPDX-License-Identifier: Apache-2.0

package consent

import (
    "crypto/sha256"
    "fmt"
    "net/url"

    "github.com/ory/x/errorsx"

    "github.com/ory/fosite"
    "github.com/ory/hydra/v2/client"
)

type SubjectIdentifierAlgorithmPairwise struct {
    Salt []byte
}

func NewSubjectIdentifierAlgorithmPairwise(salt []byte) *SubjectIdentifierAlgorithmPairwise {
    return &SubjectIdentifierAlgorithmPairwise{Salt: salt}
}

func (g *SubjectIdentifierAlgorithmPairwise) Obfuscate(subject string, client *client.Client) (string, error) {
    // sub = SHA-256 ( sector_identifier || local_account_id || salt ).
    var id string
    if len(client.SectorIdentifierURI) == 0 && len(client.RedirectURIs) > 1 {
        return "", errorsx.WithStack(fosite.ErrInvalidRequest.WithHintf("OAuth 2.0 Client %s has multiple redirect_uris but no sector_identifier_uri was set which is not allowed when performing using subject type pairwise. Please reconfigure the OAuth 2.0 client properly.", client.GetID()))
    } else if len(client.SectorIdentifierURI) == 0 && len(client.RedirectURIs) == 0 {
        return "", errorsx.WithStack(fosite.ErrInvalidRequest.WithHintf("OAuth 2.0 Client %s neither specifies a sector_identifier_uri nor a redirect_uri which is not allowed when performing using subject type pairwise. Please reconfigure the OAuth 2.0 client properly.", client.GetID()))
    } else if len(client.SectorIdentifierURI) > 0 {
        id = client.SectorIdentifierURI
    } else {
        redirectURL, err := url.Parse(client.RedirectURIs[0])
        if err != nil {
            return "", errorsx.WithStack(err)
        }
        id = redirectURL.Host
    }

    return fmt.Sprintf("%x", sha256.Sum256(append(append([]byte{}, []byte(id+subject)...), g.Salt...))), nil
}