crypto

Documentation

Index

• Constants
• Variables
• func CalculateSegments(fileSize uint64) (numSegments uint64)
• func GenerateSignatureKeys() (sk SecretKey, pk PublicKey, err error)
• func NewHash() hash.Hash
• func NewTree() tree
• func VerifyHash(data Hash, pk PublicKey, sig Signature) (err error)
• func VerifySegment(base [SegmentSize]byte, hashSet []Hash, numSegments, proofIndex uint64, ...) bool
• type Ciphertext
• type Hash
  • func BuildReaderProof(r io.Reader, proofIndex uint64) (base [SegmentSize]byte, hashSet []Hash, err error)
  • func HashAll(objs ...interface{}) Hash
  • func HashBytes(data []byte) Hash
  • func HashObject(obj interface{}) Hash
  • func MerkleRoot(leaves [][]byte) (h Hash)
  • func ReaderMerkleRoot(r io.Reader) (h Hash, err error)
• type HashSlice
  • func (hs HashSlice) Len() int
  • func (hs HashSlice) Less(i, j int) bool
  • func (hs HashSlice) Swap(i, j int)
• type PublicKey
• type SecretKey
• type Signature
  • func SignHash(data Hash, sk SecretKey) (sig Signature, err error)
• type TwofishKey
  • func GenerateTwofishKey() (key TwofishKey, err error)
  • func (key TwofishKey) DecryptBytes(ct Ciphertext) ([]byte, error)
  • func (key TwofishKey) EncryptBytes(plaintext []byte) (Ciphertext, error)
  • func (key TwofishKey) NewCipher() cipher.Block
  • func (key TwofishKey) NewReader(r io.Reader) io.Reader
  • func (key TwofishKey) NewWriter(w io.Writer) io.Writer

Constants

const (
	PublicKeySize = ed25519.PublicKeySize
	SecretKeySize = ed25519.PrivateKeySize
	SignatureSize = ed25519.SignatureSize
)

const (
	HashSize = 32
)

const (
	SegmentSize = 64 // number of bytes that are hashed to form each base leaf of the Merkle tree
)

Variables

var (
	ErrNilInput         = errors.New("cannot use nil input")
	ErrInvalidSignature = errors.New("invalid signature")
)

var (
	ErrInsufficientLen = errors.New("supplied ciphertext is not long enough to contain a nonce")
)

Functions

func CalculateSegments

func CalculateSegments(fileSize uint64) (numSegments uint64)

Calculates the number of segments in the file when building a Merkle tree. Should probably be renamed to CountLeaves() or something.

func GenerateSignatureKeys

func GenerateSignatureKeys() (sk SecretKey, pk PublicKey, err error)

GenerateKeyPair creates a public-secret keypair that can be used to sign and verify messages.

func NewHash

func NewHash() hash.Hash

func NewTree

func NewTree() tree

func VerifyHash

func VerifyHash(data Hash, pk PublicKey, sig Signature) (err error)

VerifyHash uses a public key and input data to verify a signature.

func VerifySegment

func VerifySegment(base [SegmentSize]byte, hashSet []Hash, numSegments, proofIndex uint64, root Hash) bool

Types

type Ciphertext

type Ciphertext []byte

type Hash

type Hash [HashSize]byte

func BuildReaderProof

func BuildReaderProof(r io.Reader, proofIndex uint64) (base [SegmentSize]byte, hashSet []Hash, err error)

func HashAll

func HashAll(objs ...interface{}) Hash

HashAll takes a set of objects as input, encodes them all using the encoding package, and then hashes the result.

func HashBytes

func HashBytes(data []byte) Hash

HashBytes takes a byte slice and returns the result.

func HashObject

func HashObject(obj interface{}) Hash

HashObject takes an object as input, encodes it using the encoding package, and then hashes the result.

func MerkleRoot

func MerkleRoot(leaves [][]byte) (h Hash)

MerkleRoot calculates the "root hash" formed by repeatedly concatenating and hashing a binary tree of hashes. If the number of leaves is not a power of 2, the orphan hash(es) are not rehashed. Examples:

     ┌───┴──┐       ┌────┴───┐         ┌─────┴─────┐
  ┌──┴──┐   │    ┌──┴──┐     │      ┌──┴──┐     ┌──┴──┐
┌─┴─┐ ┌─┴─┐ │  ┌─┴─┐ ┌─┴─┐ ┌─┴─┐  ┌─┴─┐ ┌─┴─┐ ┌─┴─┐   │
   (5-leaf)         (6-leaf)             (7-leaf)

func ReaderMerkleRoot

func ReaderMerkleRoot(r io.Reader) (h Hash, err error)

type HashSlice

type HashSlice []Hash

HashSlice is used for sorting

func (HashSlice) Len

func (hs HashSlice) Len() int

These functions implement sort.Interface, allowing hashes to be sorted.

func (HashSlice) Less

func (hs HashSlice) Less(i, j int) bool

func (HashSlice) Swap

func (hs HashSlice) Swap(i, j int)

type PublicKey

type PublicKey [ed25519.PublicKeySize]byte

type SecretKey

type SecretKey [ed25519.PrivateKeySize]byte

type Signature

type Signature [ed25519.SignatureSize]byte

func SignHash

func SignHash(data Hash, sk SecretKey) (sig Signature, err error)

SignHash signs a message using a secret key.

type TwofishKey

type TwofishKey [32]byte

func GenerateTwofishKey

func GenerateTwofishKey() (key TwofishKey, err error)

GenerateEncryptionKey produces a key that can be used for encrypting and decrypting files.

func (TwofishKey) DecryptBytes

func (key TwofishKey) DecryptBytes(ct Ciphertext) ([]byte, error)

DecryptBytes decrypts the ciphertext created by EncryptBytes. The nonce is expected to be the first 12 bytes of the ciphertext.

func (TwofishKey) EncryptBytes

func (key TwofishKey) EncryptBytes(plaintext []byte) (Ciphertext, error)

EncryptBytes encrypts a []byte using the key. EncryptBytes uses GCM and prepends the nonce (12 bytes) to the ciphertext.

func (TwofishKey) NewCipher

func (key TwofishKey) NewCipher() cipher.Block

NewCipher creates a new Twofish cipher from the key.

func (TwofishKey) NewReader

func (key TwofishKey) NewReader(r io.Reader) io.Reader

NewReader returns a reader that encrypts or decrypts its input stream.

func (TwofishKey) NewWriter

func (key TwofishKey) NewWriter(w io.Writer) io.Writer

NewWriter returns a writer that encrypts or decrypts its input stream.