ct

README

Certificate Transparency: Go Code

This repository holds Go code related to Certificate Transparency (CT). The repository requires Go version 1.22.

• Repository Structure
• Trillian CT Personality
• Working on the Code
  • Running Codebase Checks
  • Rebuilding Generated Code

Support

• Slack: https://transparency-dev.slack.com/ (invitation)

Repository Structure

The main parts of the repository are:

• Encoding libraries:
  • asn1/ and x509/ are forks of the upstream Go encoding/asn1 and crypto/x509 libraries. We maintain separate forks of these packages because CT is intended to act as an observatory of certificates across the ecosystem; as such, we need to be able to process somewhat-malformed certificates that the stricter upstream code would (correctly) reject. Our x509 fork also includes code for working with the pre-certificates defined in RFC 6962.
  • tls holds a library for processing TLS-encoded data as described in RFC 5246.
  • x509util/ provides additional utilities for dealing with x509.Certificates.
• CT client libraries:
  • The top-level ct package (in .) holds types and utilities for working with CT data structures defined in RFC 6962.
  • client/ and jsonclient/ hold libraries that allow access to CT Logs via HTTP entrypoints described in section 4 of RFC 6962.
  • dnsclient/ has a library that allows access to CT Logs over DNS.
  • scanner/ holds a library for scanning the entire contents of an existing CT Log.
• CT Personality for Trillian:
  • trillian/ holds code that allows a Certificate Transparency Log to be run using a Trillian Log as its back-end -- see below.
• Command line tools:
  • ./client/ctclient allows interaction with a CT Log.
  • ./ctutil/sctcheck allows SCTs (signed certificate timestamps) from a CT Log to be verified.
  • ./scanner/scanlog allows an existing CT Log to be scanned for certificates of interest; please be polite when running this tool against a Log.
  • ./x509util/certcheck allows display and verification of certificates
  • ./x509util/crlcheck allows display and verification of certificate revocation lists (CRLs).
• Other libraries related to CT:
  • ctutil/ holds utility functions for validating and verifying CT data structures.
  • loglist3/ has a library for reading v3 JSON lists of CT Logs.

Trillian CT Personality

The trillian/ subdirectory holds code and scripts for running a CT Log based on the Trillian general transparency Log, and is documented separately.

Working on the Code

Developers who want to make changes to the codebase need some additional dependencies and tools, described in the following sections.

Running Codebase Checks

The scripts/presubmit.sh script runs various tools and tests over the codebase; please ensure this script passes before sending pull requests for review.

# Install golangci-lint
go install github.com/golangci/golangci-lint/cmd/golangci-lint@v1.55.1

# Run code generation, build, test and linters
./scripts/presubmit.sh

# Run build, test and linters but skip code generation
./scripts/presubmit.sh  --no-generate

# Or just run the linters alone:
golangci-lint run

Rebuilding Generated Code

Some of the CT Go code is autogenerated from other files:

• Protocol buffer message definitions are converted to .pb.go implementations.
• A mock implementation of the Trillian gRPC API (in trillian/mockclient) is created with GoMock.

Re-generating mock or protobuffer files is only needed if you're changing the original files; if you do, you'll need to install the prerequisites:

• tools written in go can be installed with a single run of go install (courtesy of tools.go and go.mod).
• protoc tool: you'll need version 3.20.1 installed, and PATH updated to include its bin/ directory.

With tools installed, run the following:

go generate -x ./...  # hunts for //go:generate comments and runs them

Documentation

Overview

Package ct holds core types and utilities for Certificate Transparency.

Index

• Constants
• Variables
• func IsPreIssuer(issuer *x509.Certificate) bool
• func LeafHashForLeaf(leaf *MerkleTreeLeaf) ([sha256.Size]byte, error)
• func PublicKeyFromB64(b64PubKey string) (crypto.PublicKey, error)
• func SerializeSCTSignatureInput(sct SignedCertificateTimestamp, entry LogEntry) ([]byte, error)
• func SerializeSTHSignatureInput(sth SignedTreeHead) ([]byte, error)
• func TimestampToTime(ts uint64) time.Time
• type APIEndpoint
• type ASN1Cert
• type AddChainRequest
• type AddChainResponse
  • func (r *AddChainResponse) ToSignedCertificateTimestamp() (*SignedCertificateTimestamp, error)
• type AddJSONRequest
• type AuditPath
• type CTExtensions
• type CertificateChain
• type CertificateChainHash
• type CertificateTimestamp
• type ConsistencyProof
• type DigitallySigned
  • func (d DigitallySigned) Base64String() (string, error)
  • func (d *DigitallySigned) FromBase64String(b64 string) error
  • func (d DigitallySigned) MarshalJSON() ([]byte, error)
  • func (d *DigitallySigned) UnmarshalJSON(b []byte) error
• type GetEntriesResponse
• type GetEntryAndProofResponse
• type GetProofByHashResponse
• type GetRootsResponse
• type GetSTHConsistencyResponse
• type GetSTHResponse
  • func (r *GetSTHResponse) ToSignedTreeHead() (*SignedTreeHead, error)
• type JSONDataEntry
• type LeafEntry
• type LeafInput
• type LogEntry
  • func LogEntryFromLeaf(index int64, leaf *LeafEntry) (*LogEntry, error)
• type LogEntryType
  • func (e LogEntryType) String() string
• type LogID
• type MerkleLeafType
  • func (m MerkleLeafType) String() string
• type MerkleTreeLeaf
  • func CreateX509MerkleTreeLeaf(cert ASN1Cert, timestamp uint64) *MerkleTreeLeaf
  • func MerkleTreeLeafForEmbeddedSCT(chain []*x509.Certificate, timestamp uint64) (*MerkleTreeLeaf, error)
  • func MerkleTreeLeafFromChain(chain []*x509.Certificate, etype LogEntryType, timestamp uint64) (*MerkleTreeLeaf, error)
  • func MerkleTreeLeafFromRawChain(rawChain []ASN1Cert, etype LogEntryType, timestamp uint64) (*MerkleTreeLeaf, error)
  • func (m *MerkleTreeLeaf) Precertificate() (*x509.Certificate, error)
  • func (m *MerkleTreeLeaf) X509Certificate() (*x509.Certificate, error)
• type MerkleTreeNode
• type PreCert
• type PrecertChainEntry
• type PrecertChainEntryHash
• type Precertificate
• type RawLogEntry
  • func RawLogEntryFromLeaf(index int64, entry *LeafEntry) (*RawLogEntry, error)
  • func (rle *RawLogEntry) ToLogEntry() (*LogEntry, error)
• type SHA256Hash
  • func PublicKeyFromPEM(b []byte) (crypto.PublicKey, SHA256Hash, []byte, error)
  • func (s SHA256Hash) Base64String() string
  • func (s *SHA256Hash) FromBase64String(b64 string) error
  • func (s SHA256Hash) MarshalJSON() ([]byte, error)
  • func (s *SHA256Hash) UnmarshalJSON(b []byte) error
• type SignatureType
  • func (st SignatureType) String() string
• type SignatureVerifier
  • func NewSignatureVerifier(pk crypto.PublicKey) (*SignatureVerifier, error)
  • func (s SignatureVerifier) VerifySCTSignature(sct SignedCertificateTimestamp, entry LogEntry) error
  • func (s SignatureVerifier) VerifySTHSignature(sth SignedTreeHead) error
  • func (s SignatureVerifier) VerifySignature(data []byte, sig tls.DigitallySigned) error
• type SignedCertificateTimestamp
  • func (s SignedCertificateTimestamp) String() string
• type SignedTreeHead
  • func (s SignedTreeHead) String() string
• type TimestampedEntry
• type TreeHeadSignature
• type Version
  • func (v Version) String() string

Constants

const (
	TreeLeafPrefix = byte(0x00)
	TreeNodePrefix = byte(0x01)
)

RFC6962 section 2.1 requires a prefix byte on hash inputs for second preimage resistance.

const (
	AddChainPath          = "/ct/v1/add-chain"
	AddPreChainPath       = "/ct/v1/add-pre-chain"
	GetSTHPath            = "/ct/v1/get-sth"
	GetEntriesPath        = "/ct/v1/get-entries"
	GetProofByHashPath    = "/ct/v1/get-proof-by-hash"
	GetSTHConsistencyPath = "/ct/v1/get-sth-consistency"
	GetRootsPath          = "/ct/v1/get-roots"
	GetEntryAndProofPath  = "/ct/v1/get-entry-and-proof"

	AddJSONPath = "/ct/v1/add-json" // Experimental addition
)

URI paths for Log requests; see section 4. WARNING: Should match the API endpoints, with the "/ct/v1/" prefix. If changing these constants, may need to change those too.

Variables

var AllowVerificationWithNonCompliantKeys = false

AllowVerificationWithNonCompliantKeys may be set to true in order to allow SignatureVerifier to use keys which are technically non-compliant with RFC6962.

Functions

func IsPreIssuer

func IsPreIssuer(issuer *x509.Certificate) bool

IsPreIssuer indicates whether a certificate is a pre-cert issuer with the specific certificate transparency extended key usage.

func LeafHashForLeaf

func LeafHashForLeaf(leaf *MerkleTreeLeaf) ([sha256.Size]byte, error)

LeafHashForLeaf returns the leaf hash for a Merkle tree leaf.

func PublicKeyFromB64

func PublicKeyFromB64(b64PubKey string) (crypto.PublicKey, error)

PublicKeyFromB64 parses a base64-encoded public key.

func SerializeSCTSignatureInput

func SerializeSCTSignatureInput(sct SignedCertificateTimestamp, entry LogEntry) ([]byte, error)

SerializeSCTSignatureInput serializes the passed in sct and log entry into the correct format for signing.

func SerializeSTHSignatureInput

func SerializeSTHSignatureInput(sth SignedTreeHead) ([]byte, error)

SerializeSTHSignatureInput serializes the passed in STH into the correct format for signing.

func TimestampToTime

func TimestampToTime(ts uint64) time.Time

TimestampToTime converts a timestamp in the style of RFC 6962 (milliseconds since UNIX epoch) to a Go Time.

Types

type APIEndpoint

type APIEndpoint string

APIEndpoint is a string that represents one of the Certificate Transparency Log API endpoints.

const (
	AddChainStr          APIEndpoint = "add-chain"
	AddPreChainStr       APIEndpoint = "add-pre-chain"
	GetSTHStr            APIEndpoint = "get-sth"
	GetEntriesStr        APIEndpoint = "get-entries"
	GetProofByHashStr    APIEndpoint = "get-proof-by-hash"
	GetSTHConsistencyStr APIEndpoint = "get-sth-consistency"
	GetRootsStr          APIEndpoint = "get-roots"
	GetEntryAndProofStr  APIEndpoint = "get-entry-and-proof"
)

Certificate Transparency Log API endpoints; see section 4. WARNING: Should match the URI paths without the "/ct/v1/" prefix. If changing these constants, may need to change those too.

type ASN1Cert

type ASN1Cert struct {
	Data []byte `tls:"minlen:1,maxlen:16777215"`
}

ASN1Cert type for holding the raw DER bytes of an ASN.1 Certificate (section 3.1).

type AddChainRequest

type AddChainRequest struct {
	Chain [][]byte `json:"chain"`
}

AddChainRequest represents the JSON request body sent to the add-chain and add-pre-chain POST methods from sections 4.1 and 4.2.

type AddChainResponse

type AddChainResponse struct {
	SCTVersion Version `json:"sct_version"` // SCT structure version
	ID         []byte  `json:"id"`          // Log ID
	Timestamp  uint64  `json:"timestamp"`   // Timestamp of issuance
	Extensions string  `json:"extensions"`  // Holder for any CT extensions
	Signature  []byte  `json:"signature"`   // Log signature for this SCT
}

AddChainResponse represents the JSON response to the add-chain and add-pre-chain POST methods. An SCT represents a Log's promise to integrate a [pre-]certificate into the log within a defined period of time.

func (*AddChainResponse) ToSignedCertificateTimestamp

func (r *AddChainResponse) ToSignedCertificateTimestamp() (*SignedCertificateTimestamp, error)

ToSignedCertificateTimestamp creates a SignedCertificateTimestamp from the AddChainResponse.

type AddJSONRequest

type AddJSONRequest struct {
	Data interface{} `json:"data"`
}

AddJSONRequest represents the JSON request body sent to the add-json POST method. The corresponding response re-uses AddChainResponse. This is an experimental addition not covered by RFC6962.

type AuditPath

type AuditPath []MerkleTreeNode

AuditPath represents a CT inclusion proof (see sections 2.1.1 and 4.5).

type CTExtensions

type CTExtensions []byte // tls:"minlen:0,maxlen:65535"`

CTExtensions is a representation of the raw bytes of any CtExtension structure (see section 3.2). nolint: revive

type CertificateChain

type CertificateChain struct {
	Entries []ASN1Cert `tls:"minlen:0,maxlen:16777215"`
}

CertificateChain holds a chain of certificates, as returned as extra data for get-entries (section 4.6).

type CertificateChainHash

type CertificateChainHash struct {
	IssuanceChainHash []byte `tls:"minlen:0,maxlen:256"`
}

CertificateChainHash is an extended CertificateChain type with the IssuanceChainHash field added to store the hash of the Entries field of CertificateChain.

type CertificateTimestamp

type CertificateTimestamp struct {
	SCTVersion    Version       `tls:"maxval:255"`
	SignatureType SignatureType `tls:"maxval:255"`
	Timestamp     uint64
	EntryType     LogEntryType   `tls:"maxval:65535"`
	X509Entry     *ASN1Cert      `tls:"selector:EntryType,val:0"`
	PrecertEntry  *PreCert       `tls:"selector:EntryType,val:1"`
	JSONEntry     *JSONDataEntry `tls:"selector:EntryType,val:32768"`
	Extensions    CTExtensions   `tls:"minlen:0,maxlen:65535"`
}

CertificateTimestamp is the collection of data that the signature in an SCT is over; see section 3.2.

type ConsistencyProof

type ConsistencyProof []MerkleTreeNode

ConsistencyProof represents a CT consistency proof (see sections 2.1.2 and 4.4).

type DigitallySigned

type DigitallySigned tls.DigitallySigned

DigitallySigned is a local alias for tls.DigitallySigned so that we can attach a MarshalJSON method.

func (DigitallySigned) Base64String

func (d DigitallySigned) Base64String() (string, error)

Base64String returns the base64 representation of the DigitallySigned struct.

func (*DigitallySigned) FromBase64String

func (d *DigitallySigned) FromBase64String(b64 string) error

FromBase64String populates the DigitallySigned structure from the base64 data passed in. Returns an error if the base64 data is invalid.

func (DigitallySigned) MarshalJSON

func (d DigitallySigned) MarshalJSON() ([]byte, error)

MarshalJSON implements the json.Marshaller interface.

func (*DigitallySigned) UnmarshalJSON

func (d *DigitallySigned) UnmarshalJSON(b []byte) error

UnmarshalJSON implements the json.Unmarshaler interface.

type GetEntriesResponse

type GetEntriesResponse struct {
	Entries []LeafEntry `json:"entries"` // the list of returned entries
}

GetEntriesResponse represents the JSON response to the get-entries GET method from section 4.6.

type GetEntryAndProofResponse

type GetEntryAndProofResponse struct {
	LeafInput []byte   `json:"leaf_input"` // the entry itself
	ExtraData []byte   `json:"extra_data"` // any chain provided when the entry was added to the log
	AuditPath [][]byte `json:"audit_path"` // the corresponding proof
}

GetEntryAndProofResponse represents the JSON response to the get-entry-and-proof GET method from section 4.8. (The corresponding GET request has parameters 'leaf_index' and 'tree_size'.)

type GetProofByHashResponse

type GetProofByHashResponse struct {
	LeafIndex int64    `json:"leaf_index"` // The 0-based index of the end entity corresponding to the "hash" parameter.
	AuditPath [][]byte `json:"audit_path"` // An array of base64-encoded Merkle Tree nodes proving the inclusion of the chosen certificate.
}

GetProofByHashResponse represents the JSON response to the get-proof-by-hash GET method from section 4.5. (The corresponding GET request has parameters 'hash' and 'tree_size'.)

type GetRootsResponse

type GetRootsResponse struct {
	Certificates []string `json:"certificates"`
}

GetRootsResponse represents the JSON response to the get-roots GET method from section 4.7.

type GetSTHConsistencyResponse

type GetSTHConsistencyResponse struct {
	Consistency [][]byte `json:"consistency"`
}

GetSTHConsistencyResponse represents the JSON response to the get-sth-consistency GET method from section 4.4. (The corresponding GET request has parameters 'first' and 'second'.)

type GetSTHResponse

type GetSTHResponse struct {
	TreeSize          uint64 `json:"tree_size"`           // Number of certs in the current tree
	Timestamp         uint64 `json:"timestamp"`           // Time that the tree was created
	SHA256RootHash    []byte `json:"sha256_root_hash"`    // Root hash of the tree
	TreeHeadSignature []byte `json:"tree_head_signature"` // Log signature for this STH
}

GetSTHResponse represents the JSON response to the get-sth GET method from section 4.3.

func (*GetSTHResponse) ToSignedTreeHead

func (r *GetSTHResponse) ToSignedTreeHead() (*SignedTreeHead, error)

ToSignedTreeHead creates a SignedTreeHead from the GetSTHResponse.

type JSONDataEntry

type JSONDataEntry struct {
	Data []byte `tls:"minlen:0,maxlen:1677215"`
}

JSONDataEntry holds arbitrary data.

type LeafEntry

type LeafEntry struct {
	// LeafInput is a TLS-encoded MerkleTreeLeaf
	LeafInput []byte `json:"leaf_input"`
	// ExtraData holds (unsigned) extra data, normally the cert validation chain.
	ExtraData []byte `json:"extra_data"`
}

LeafEntry represents a leaf in the Log's Merkle tree, as returned by the get-entries GET method from section 4.6.

type LeafInput

type LeafInput []byte

LeafInput represents a serialized MerkleTreeLeaf structure.

type LogEntry

type LogEntry struct {
	Index int64
	Leaf  MerkleTreeLeaf
	// Exactly one of the following three fields should be non-empty.
	X509Cert *x509.Certificate // Parsed X.509 certificate
	Precert  *Precertificate   // Extracted precertificate
	JSONData []byte

	// Chain holds the issuing certificate chain, starting with the
	// issuer of the leaf certificate / pre-certificate.
	Chain []ASN1Cert
}

LogEntry represents the (parsed) contents of an entry in a CT log. This is described in section 3.1, but note that this structure does *not* match the TLS structure defined there (the TLS structure is never used directly in RFC6962).

func LogEntryFromLeaf

func LogEntryFromLeaf(index int64, leaf *LeafEntry) (*LogEntry, error)

LogEntryFromLeaf converts a LeafEntry object (which has the raw leaf data after JSON parsing) into a LogEntry object (which includes x509.Certificate objects, after TLS and ASN.1 parsing).

Note that this function may return a valid LogEntry object and a non-nil error value, when the error indicates a non-fatal parsing error.

type LogEntryType

type LogEntryType tls.Enum // tls:"maxval:65535"

LogEntryType represents the LogEntryType enum from section 3.1:

enum { x509_entry(0), precert_entry(1), (65535) } LogEntryType;

const (
	X509LogEntryType    LogEntryType = 0
	PrecertLogEntryType LogEntryType = 1
)

LogEntryType constants from section 3.1.

func (LogEntryType) String

func (e LogEntryType) String() string

type LogID

type LogID struct {
	KeyID [sha256.Size]byte
}

LogID holds the hash of the Log's public key (section 3.2). TODO(pphaneuf): Users should be migrated to the one in the logid package.

type MerkleLeafType

type MerkleLeafType tls.Enum // tls:"maxval:255"

MerkleLeafType represents the MerkleLeafType enum from section 3.4:

enum { timestamped_entry(0), (255) } MerkleLeafType;

const TimestampedEntryLeafType MerkleLeafType = 0 // Entry type for an SCT

TimestampedEntryLeafType is the only defined MerkleLeafType constant from section 3.4.

func (MerkleLeafType) String

func (m MerkleLeafType) String() string

type MerkleTreeLeaf

type MerkleTreeLeaf struct {
	Version          Version           `tls:"maxval:255"`
	LeafType         MerkleLeafType    `tls:"maxval:255"`
	TimestampedEntry *TimestampedEntry `tls:"selector:LeafType,val:0"`
}

MerkleTreeLeaf represents the deserialized structure of the hash input for the leaves of a log's Merkle tree; see section 3.4.

func CreateX509MerkleTreeLeaf

func CreateX509MerkleTreeLeaf(cert ASN1Cert, timestamp uint64) *MerkleTreeLeaf

CreateX509MerkleTreeLeaf generates a MerkleTreeLeaf for an X509 cert

func MerkleTreeLeafForEmbeddedSCT

func MerkleTreeLeafForEmbeddedSCT(chain []*x509.Certificate, timestamp uint64) (*MerkleTreeLeaf, error)

MerkleTreeLeafForEmbeddedSCT generates a MerkleTreeLeaf from a chain and an SCT timestamp, where the leaf certificate at chain[0] is a certificate that contains embedded SCTs. It is assumed that the timestamp provided is from one of the SCTs embedded within the leaf certificate.

func MerkleTreeLeafFromChain

func MerkleTreeLeafFromChain(chain []*x509.Certificate, etype LogEntryType, timestamp uint64) (*MerkleTreeLeaf, error)

MerkleTreeLeafFromChain generates a MerkleTreeLeaf from a chain and timestamp.

func MerkleTreeLeafFromRawChain

func MerkleTreeLeafFromRawChain(rawChain []ASN1Cert, etype LogEntryType, timestamp uint64) (*MerkleTreeLeaf, error)

MerkleTreeLeafFromRawChain generates a MerkleTreeLeaf from a chain (in DER-encoded form) and timestamp.

func (*MerkleTreeLeaf) Precertificate

func (m *MerkleTreeLeaf) Precertificate() (*x509.Certificate, error)

Precertificate returns the X.509 Precertificate contained within the MerkleTreeLeaf.

The returned precertificate is embedded in an x509.Certificate, but is in the form stored internally in the log rather than the original submitted form (i.e. it does not include the poison extension and any changes to reflect the final certificate's issuer have been made; see x509.BuildPrecertTBS).

func (*MerkleTreeLeaf) X509Certificate

func (m *MerkleTreeLeaf) X509Certificate() (*x509.Certificate, error)

X509Certificate returns the X.509 Certificate contained within the MerkleTreeLeaf.

type MerkleTreeNode

type MerkleTreeNode []byte

MerkleTreeNode represents an internal node in the CT tree.

type PreCert

type PreCert struct {
	IssuerKeyHash  [sha256.Size]byte
	TBSCertificate []byte `tls:"minlen:1,maxlen:16777215"` // DER-encoded TBSCertificate
}

PreCert represents a Precertificate (section 3.2).

type PrecertChainEntry

type PrecertChainEntry struct {
	PreCertificate   ASN1Cert   `tls:"minlen:1,maxlen:16777215"`
	CertificateChain []ASN1Cert `tls:"minlen:0,maxlen:16777215"`
}

PrecertChainEntry holds an precertificate together with a validation chain for it; see section 3.1.

type PrecertChainEntryHash

type PrecertChainEntryHash struct {
	PreCertificate    ASN1Cert `tls:"minlen:1,maxlen:16777215"`
	IssuanceChainHash []byte   `tls:"minlen:0,maxlen:256"`
}

PrecertChainEntryHash is an extended PrecertChainEntry type with the IssuanceChainHash field added to store the hash of the CertificateChain field of PrecertChainEntry.

type Precertificate

type Precertificate struct {
	// DER-encoded pre-certificate as originally added, which includes a
	// poison extension and a signature generated over the pre-cert by
	// the pre-cert issuer (which might differ from the issuer of the final
	// cert, see RFC6962 s3.1).
	Submitted ASN1Cert
	// SHA256 hash of the issuing key
	IssuerKeyHash [sha256.Size]byte
	// Parsed TBSCertificate structure, held in an x509.Certificate for convenience.
	TBSCertificate *x509.Certificate
}

Precertificate represents the parsed CT Precertificate structure.

type RawLogEntry

type RawLogEntry struct {
	// Index is a position of the entry in the log.
	Index int64
	// Leaf is a parsed Merkle leaf hash input.
	Leaf MerkleTreeLeaf
	// Cert is:
	// - A certificate if Leaf.TimestampedEntry.EntryType is X509LogEntryType.
	// - A precertificate if Leaf.TimestampedEntry.EntryType is
	//   PrecertLogEntryType, in the form of a DER-encoded Certificate as
	//   originally added (which includes the poison extension and a signature
	//   generated over the pre-cert by the pre-cert issuer).
	// - Empty otherwise.
	Cert ASN1Cert
	// Chain is the issuing certificate chain starting with the issuer of Cert,
	// or an empty slice if Cert is empty.
	Chain []ASN1Cert
}

RawLogEntry represents the (TLS-parsed) contents of an entry in a CT log.

func RawLogEntryFromLeaf

func RawLogEntryFromLeaf(index int64, entry *LeafEntry) (*RawLogEntry, error)

RawLogEntryFromLeaf converts a LeafEntry object (which has the raw leaf data after JSON parsing) into a RawLogEntry object (i.e. a TLS-parsed structure).

func (*RawLogEntry) ToLogEntry

func (rle *RawLogEntry) ToLogEntry() (*LogEntry, error)

ToLogEntry converts RawLogEntry to a LogEntry, which includes an x509-parsed (pre-)certificate.

Note that this function may return a valid LogEntry object and a non-nil error value, when the error indicates a non-fatal parsing error.

type SHA256Hash

type SHA256Hash [sha256.Size]byte

SHA256Hash represents the output from the SHA256 hash function.

func PublicKeyFromPEM

func PublicKeyFromPEM(b []byte) (crypto.PublicKey, SHA256Hash, []byte, error)

PublicKeyFromPEM parses a PEM formatted block and returns the public key contained within and any remaining unread bytes, or an error.

func (SHA256Hash) Base64String

func (s SHA256Hash) Base64String() string

Base64String returns the base64 representation of this SHA256Hash.

func (*SHA256Hash) FromBase64String

func (s *SHA256Hash) FromBase64String(b64 string) error

FromBase64String populates the SHA256 struct with the contents of the base64 data passed in.

func (SHA256Hash) MarshalJSON

func (s SHA256Hash) MarshalJSON() ([]byte, error)

MarshalJSON implements the json.Marshaller interface for SHA256Hash.

func (*SHA256Hash) UnmarshalJSON

func (s *SHA256Hash) UnmarshalJSON(b []byte) error

UnmarshalJSON implements the json.Unmarshaller interface.

type SignatureType

type SignatureType tls.Enum // tls:"maxval:255"

SignatureType differentiates STH signatures from SCT signatures, see section 3.2.

enum { certificate_timestamp(0), tree_hash(1), (255) } SignatureType;

const (
	CertificateTimestampSignatureType SignatureType = 0
	TreeHashSignatureType             SignatureType = 1
)

SignatureType constants from section 3.2.

func (SignatureType) String

func (st SignatureType) String() string

type SignatureVerifier

type SignatureVerifier struct {
	PubKey crypto.PublicKey
}

SignatureVerifier can verify signatures on SCTs and STHs

func NewSignatureVerifier

func NewSignatureVerifier(pk crypto.PublicKey) (*SignatureVerifier, error)

NewSignatureVerifier creates a new SignatureVerifier using the passed in PublicKey.

func (SignatureVerifier) VerifySCTSignature

func (s SignatureVerifier) VerifySCTSignature(sct SignedCertificateTimestamp, entry LogEntry) error

VerifySCTSignature verifies that the SCT's signature is valid for the given LogEntry.

func (SignatureVerifier) VerifySTHSignature

func (s SignatureVerifier) VerifySTHSignature(sth SignedTreeHead) error

VerifySTHSignature verifies that the STH's signature is valid.

func (SignatureVerifier) VerifySignature

func (s SignatureVerifier) VerifySignature(data []byte, sig tls.DigitallySigned) error

VerifySignature verifies the given signature sig matches the data.

type SignedCertificateTimestamp

type SignedCertificateTimestamp struct {
	SCTVersion Version `tls:"maxval:255"`
	LogID      LogID
	Timestamp  uint64
	Extensions CTExtensions    `tls:"minlen:0,maxlen:65535"`
	Signature  DigitallySigned // Signature over TLS-encoded CertificateTimestamp
}

SignedCertificateTimestamp represents the structure returned by the add-chain and add-pre-chain methods after base64 decoding; see sections 3.2, 4.1 and 4.2.

func (SignedCertificateTimestamp) String

func (s SignedCertificateTimestamp) String() string

type SignedTreeHead

type SignedTreeHead struct {
	Version           Version         `json:"sth_version"`         // The version of the protocol to which the STH conforms
	TreeSize          uint64          `json:"tree_size"`           // The number of entries in the new tree
	Timestamp         uint64          `json:"timestamp"`           // The time at which the STH was created
	SHA256RootHash    SHA256Hash      `json:"sha256_root_hash"`    // The root hash of the log's Merkle tree
	TreeHeadSignature DigitallySigned `json:"tree_head_signature"` // Log's signature over a TLS-encoded TreeHeadSignature
	LogID             SHA256Hash      `json:"log_id"`              // The SHA256 hash of the log's public key
}

SignedTreeHead represents the structure returned by the get-sth CT method after base64 decoding; see sections 3.5 and 4.3.

func (SignedTreeHead) String

func (s SignedTreeHead) String() string

type TimestampedEntry

type TimestampedEntry struct {
	Timestamp    uint64
	EntryType    LogEntryType   `tls:"maxval:65535"`
	X509Entry    *ASN1Cert      `tls:"selector:EntryType,val:0"`
	PrecertEntry *PreCert       `tls:"selector:EntryType,val:1"`
	JSONEntry    *JSONDataEntry `tls:"selector:EntryType,val:32768"`
	Extensions   CTExtensions   `tls:"minlen:0,maxlen:65535"`
}

TimestampedEntry is part of the MerkleTreeLeaf structure; see section 3.4.

type TreeHeadSignature

type TreeHeadSignature struct {
	Version        Version       `tls:"maxval:255"`
	SignatureType  SignatureType `tls:"maxval:255"` // == TreeHashSignatureType
	Timestamp      uint64
	TreeSize       uint64
	SHA256RootHash SHA256Hash
}

TreeHeadSignature holds the data over which the signature in an STH is generated; see section 3.5

type Version

type Version tls.Enum // tls:"maxval:255"

Version represents the Version enum from section 3.2:

enum { v1(0), (255) } Version;

const (
	V1 Version = 0
)

CT Version constants from section 3.2.

func (Version) String

func (v Version) String() string