dsse

Documentation

Overview

Package dsse implements the Dead Simple Signing Envelope (DSSE) https://github.com/secure-systems-lab/dsse

Index

• Variables
• func PAE(payloadType string, payload []byte) []byte
• func SHA256KeyID(pub crypto.PublicKey) (string, error)
• type AcceptedKey
• type Envelope
  • func (e *Envelope) DecodeB64Payload() ([]byte, error)
• type EnvelopeSigner
  • func NewEnvelopeSigner(p ...Signer) (*EnvelopeSigner, error)
  • func NewMultiEnvelopeSigner(threshold int, p ...Signer) (*EnvelopeSigner, error)
  • func (es *EnvelopeSigner) SignPayload(ctx context.Context, payloadType string, body []byte) (*Envelope, error)
• type EnvelopeVerifier
  • func NewEnvelopeVerifier(v ...Verifier) (*EnvelopeVerifier, error)
  • func NewMultiEnvelopeVerifier(threshold int, p ...Verifier) (*EnvelopeVerifier, error)
  • func (ev *EnvelopeVerifier) Verify(ctx context.Context, e *Envelope) ([]AcceptedKey, error)
• type SignVerifier
• type Signature
• type Signer
• type SignerVerifier
• type Verifier

Variables

var ErrNoSignature = errors.New("no signature found")

ErrNoSignature indicates that an envelope did not contain any signatures.

var ErrNoSigners = errors.New("no signers provided")

ErrNoSigners indicates that no signer was provided.

Functions

func PAE

func PAE(payloadType string, payload []byte) []byte

PAE implementes the DSSE Pre-Authentic Encoding https://github.com/secure-systems-lab/dsse/blob/master/protocol.md#signature-definition

func SHA256KeyID

func SHA256KeyID(pub crypto.PublicKey) (string, error)

Types

type AcceptedKey

type AcceptedKey struct {
	Public crypto.PublicKey
	KeyID  string
	Sig    Signature
}

type Envelope

type Envelope struct {
	PayloadType string      `json:"payloadType"`
	Payload     string      `json:"payload"`
	Signatures  []Signature `json:"signatures"`
}

Envelope captures an envelope as described by the DSSE specification. See here: https://github.com/secure-systems-lab/dsse/blob/master/envelope.md

func (*Envelope) DecodeB64Payload

func (e *Envelope) DecodeB64Payload() ([]byte, error)

DecodeB64Payload returns the serialized body, decoded from the envelope's payload field. A flexible decoder is used, first trying standard base64, then URL-encoded base64.

type EnvelopeSigner

type EnvelopeSigner struct {
	// contains filtered or unexported fields
}

EnvelopeSigner creates signed Envelopes.

func NewEnvelopeSigner

func NewEnvelopeSigner(p ...Signer) (*EnvelopeSigner, error)

NewEnvelopeSigner creates an EnvelopeSigner that uses 1+ Signer algorithms to sign the data.

func NewMultiEnvelopeSigner

func NewMultiEnvelopeSigner(threshold int, p ...Signer) (*EnvelopeSigner, error)

NewMultiEnvelopeSigner creates an EnvelopeSigner that uses 1+ Signer algorithms to sign the data. The threshold parameter is legacy and is ignored.

Deprecated: This function simply calls NewEnvelopeSigner, and that function should be preferred.

func (*EnvelopeSigner) SignPayload

func (es *EnvelopeSigner) SignPayload(ctx context.Context, payloadType string, body []byte) (*Envelope, error)

SignPayload signs a payload and payload type according to DSSE. Returned is an envelope as defined here: https://github.com/secure-systems-lab/dsse/blob/master/envelope.md One signature will be added for each Signer in the EnvelopeSigner.

type EnvelopeVerifier

type EnvelopeVerifier struct {
	// contains filtered or unexported fields
}

func NewEnvelopeVerifier

func NewEnvelopeVerifier(v ...Verifier) (*EnvelopeVerifier, error)

func NewMultiEnvelopeVerifier

func NewMultiEnvelopeVerifier(threshold int, p ...Verifier) (*EnvelopeVerifier, error)

func (*EnvelopeVerifier) Verify

func (ev *EnvelopeVerifier) Verify(ctx context.Context, e *Envelope) ([]AcceptedKey, error)

type SignVerifier

type SignVerifier = SignerVerifier

Deprecated: switch to renamed SignerVerifier. This is currently aliased for backwards compatibility.

type Signature

type Signature struct {
	KeyID string `json:"keyid"`
	Sig   string `json:"sig"`
}

Signature represents a generic in-toto signature that contains the identifier of the key which was used to create the signature. The used signature scheme has to be agreed upon by the signer and verifer out of band. The signature is a base64 encoding of the raw bytes from the signature algorithm.

type Signer

type Signer interface {
	Sign(ctx context.Context, data []byte) ([]byte, error)
	KeyID() (string, error)
}

Signer defines the interface for an abstract signing algorithm. The Signer interface is used to inject signature algorithm implementations into the EnvelopeSigner. This decoupling allows for any signing algorithm and key management system can be used. The full message is provided as the parameter. If the signature algorithm depends on hashing of the message prior to signature calculation, the implementor of this interface must perform such hashing. The function must return raw bytes representing the calculated signature using the current algorithm, and the key used (if applicable).

type SignerVerifier

type SignerVerifier interface {
	Signer
	Verifier
}

SignerVerifier provides both the signing and verification interface.

type Verifier

type Verifier interface {
	Verify(ctx context.Context, data, sig []byte) error
	KeyID() (string, error)
	Public() crypto.PublicKey
}

Verifier verifies a complete message against a signature and key. If the message was hashed prior to signature generation, the verifier must perform the same steps. If KeyID returns successfully, only signature matching the key ID will be verified.