credentials

type AttestedClaim ¶

type AttestedClaim struct {
	Credential    *gabi.Credential `json:"credential"`
	UpdateCounter uint64           `json:"updateCounter"`
	Claim         Claim            `json:"claim"`
}

AttestedClaim contains the Claim and the gabi.Credential. It can be used to disclose specific attributes to the verifier.

func NewAttestedClaim(cb *gabi.CredentialBuilder, attributes []*Attribute, signature *gabi.IssueSignatureMessage) (*AttestedClaim, error)

func (attestedClaim *AttestedClaim) Update(attesterPubK *gabi.PublicKey, update *revocation.Update) error

func (attestedClaim *AttestedClaim) UpdateAll(attesterPubK *gabi.PublicKey,
	updates []*revocation.Update) error

type AttestedClaimRequest ¶

type AttestedClaimRequest struct {
	CommitMsg *gabi.IssueCommitmentMessage `json:"commitMsg"`
	Claim     Claim                        `json:"claim"`
}

AttestedClaimRequest is send from the claimer to the attester as a response to the StartSessionMsg. It contains the values which should get attested.

type Attester ¶

type Attester struct {
	PrivateKey *gabi.PrivateKey `json:"PrivateKey"`
	PublicKey  *gabi.PublicKey  `json:"PublicKey"`
}

Attester can attest claims.

func NewAttester(sysParams *gabi.SystemParameters, attributeCount int, periodOfValidity int64) (*Attester, error)

func (attester *Attester) AttestClaim(reqCred *AttestedClaimRequest, session *AttesterSession, update *revocation.Update) (*gabi.IssueSignatureMessage, *revocation.Witness, error)

func (attester *Attester) CreateAccumulator() (*revocation.Update, error)

func (attester *Attester) InitiateAttestation() (*AttesterSession, *StartSessionMsg, error)

func (attester *Attester) RevokeAttestation(update *revocation.Update, witnesses []*revocation.Witness) (*revocation.Update, error)

type AttesterSession ¶

type AttesterSession struct {
	Context *big.Int `json:"context"`
	Nonce   *big.Int `json:"nonce"`
}

AttesterSession contains information needed by the attester to create an attestation

type Attribute ¶

type Attribute struct {
	Name     string `json:"name"`
	Typename string `json:"typename"`
	Value    []byte `json:"value"`
}

Attribute describes an attribute. It specifies the name and the type of the attribute. It should not contain the specific value of the attribute since this struct will be send to the verifier.

func BigIntsToAttributes(encodedAttributes []*big.Int) ([]*Attribute, error)

func (p Attribute) MarshalBinary() ([]byte, error)

func (p *Attribute) UnmarshalBinary(data []byte) error

type Claim ¶

type Claim map[string]interface{}

Claim contains the attributes the claimer claims to possess. Contents should be structures according to the specified ctype.

A claim represents any valid json data. Claims are represented using a map[string]interface{}. In order to build a credential from a claim, the claim needs to be transformed into an array of attributes. This is done using the following scheme:

1. go through the claim (map[string]interface{}) for each simple time or array: transform the value into bytes and store it together with type and path (inside the json "tree"). We receive a list of attributes
2. transform each of these attributes into a big.Int big.Int := bytes(Len(Name)|Name|len(Type)|type|len(value)|value)

func VerifyCombinedPresentation(attesterPubKeys []*gabi.PublicKey,
	latestAccs []*revocation.SignedAccumulator, combinedPresentation *CombinedPresentationResponse,
	session *CombinedVerifierSession) (bool, []Claim, error)

func VerifyPresentation(issuerPubK *gabi.PublicKey, latestAcc *revocation.SignedAccumulator,
	signedAttributes *PresentationResponse, session *VerifierSession) (bool, Claim, error)

func (claim Claim) ToAttributes() []*Attribute

type Claimer ¶

type Claimer struct {
	MasterSecret *big.Int `json:"MasterSecret"`
}

Claimer contains information about the claimer.

func NewClaimer(sysParams *gabi.SystemParameters) (*Claimer, error)

func NewClaimerFromSecret(sysParams *gabi.SystemParameters, seed []byte) (*Claimer, error)

func (user *Claimer) BuildCombinedPresentation(pubKs []*gabi.PublicKey, credentials []*AttestedClaim,
	reqAttributes *CombinedPresentationRequest) (*CombinedPresentationResponse, error)

func (user *Claimer) BuildCredential(signature *gabi.IssueSignatureMessage, session *UserIssuanceSession) (*AttestedClaim, error)

func (user *Claimer) BuildPresentation(pk *gabi.PublicKey, attestedClaim *AttestedClaim, reqAttributes *PresentationRequest) (*PresentationResponse, error)

func (user *Claimer) RequestAttestationForClaim(attesterPubK *gabi.PublicKey, startMsg *StartSessionMsg, claim Claim) (*UserIssuanceSession, *AttestedClaimRequest, error)

type CombinedPresentationRequest ¶

type CombinedPresentationRequest struct {
	PartialRequests []PartialPresentationRequest `json:"partialPresentationRequests"`
	Context         *big.Int                     `json:"context"`
	Nonce           *big.Int                     `json:"nonce"`
}

CombinedPresentationRequest request multiple credentials from a claimer

type CombinedPresentationResponse ¶

type CombinedPresentationResponse struct {
	Proof gabi.ProofList `json:"prooflist"`
}

CombinedPresentationResponse contains a list of proofs. It can be used to reconstruct multiple claims.

type CombinedVerifierSession ¶

type CombinedVerifierSession struct {
	Context         *big.Int                     `json:"context"`
	Nonce           *big.Int                     `json:"nonce"`
	PartialRequests []PartialPresentationRequest `json:"partialRequests"`
}

CombinedVerifierSession stores the information for a combined presentation session.

type PartialPresentationRequest ¶

type PartialPresentationRequest struct {
	RequestedAttributes   []string  `json:"requestedAttributes"`
	ReqNonRevocationProof bool      `json:"reqNonRevocationProof"`
	ReqUpdatedAfter       time.Time `json:"reqUpdatedAfter"`
}

PartialPresentationRequest contains partial information for a combined disclosure request

type PresentationRequest ¶

type PresentationRequest struct {
	PartialPresentationRequest *PartialPresentationRequest `json:"partialPresentationRequest"`
	Context                    *big.Int                    `json:"context"`
	Nonce                      *big.Int                    `json:"nonce"`
}

PresentationRequest is send from the verifier to the claimer. The verifier request specific attributes from the claimer.

type PresentationResponse ¶

type PresentationResponse struct {
	Proof gabi.ProofD `json:"proof"`
}

PresentationResponse represents the message that is send from the claimer to the verifier in order to disclose attributes. All disclosed attributes are inside the Proof. There should be no attributes elsewhere.

type StartSessionMsg ¶

type StartSessionMsg struct {
	Nonce   *big.Int `json:"nonce"`
	Context *big.Int `json:"context"`
}

StartSessionMsg is send from the attester to the claimer to start the attestation session

type UserIssuanceSession ¶

type UserIssuanceSession struct {
	Cb    *gabi.CredentialBuilder `json:"cb"`
	Claim Claim                   `json:"claim"`
}

UserIssuanceSession stores information which are used only by the user during the attestation of claims

type VerifierSession ¶

type VerifierSession struct {
	Context               *big.Int  `json:"context"`
	Nonce                 *big.Int  `json:"nonce"`
	ReqNonRevocationProof bool      `json:"reqNonRevocationProof"`
	ReqUpdatedAfter       time.Time `json:"reqUpdatedAfter"`
}

VerifierSession stores information which is needed to verify the response of the claimer