crypto

package
v1.3.7 Latest Latest
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Published: Aug 12, 2018 License: MIT Imports: 13 Imported by: 413

Documentation

Index

Constants

View Source
const (
	// EntropySize defines the amount of entropy necessary to do secure
	// cryptographic operations, in bytes.
	EntropySize = 32

	// PublicKeySize defines the size of public keys in bytes.
	PublicKeySize = ed25519.PublicKeySize

	// SecretKeySize defines the size of secret keys in bytes.
	SecretKeySize = ed25519.PrivateKeySize

	// SignatureSize defines the size of signatures in bytes.
	SignatureSize = ed25519.SignatureSize
)
View Source
const (
	// HashSize is the length of a Hash in bytes.
	HashSize = 32
)
View Source
const (
	// SegmentSize is the chunk size that is used when taking the Merkle root
	// of a file. 64 is chosen because bandwidth is scarce and it optimizes for
	// the smallest possible storage proofs. Using a larger base, even 256
	// bytes, would result in substantially faster hashing, but the bandwidth
	// tradeoff was deemed to be more important, as blockchain space is scarce.
	SegmentSize = 64
)
View Source
const (
	// TwofishOverhead is the number of bytes added by EncryptBytes
	TwofishOverhead = 28
)

Variables

View Source
var (
	// ErrHashWrongLen is the error when encoded value has the wrong
	// length to be a hash.
	ErrHashWrongLen = errors.New("encoded value has the wrong length to be a hash")
)
View Source
var (
	// ErrInsufficientLen is an error when supplied ciphertext is not
	// long enough to contain a nonce.
	ErrInsufficientLen = errors.New("supplied ciphertext is not long enough to contain a nonce")
)
View Source
var (
	// ErrInvalidSignature is returned if a signature is provided that does not
	// match the data and public key.
	ErrInvalidSignature = errors.New("invalid signature")
)

Functions

func CalculateLeaves added in v0.3.3

func CalculateLeaves(dataSize uint64) uint64

CalculateLeaves calculates the number of leaves that would be pushed from data of size 'dataSize'.

func GenerateKeyPair added in v1.0.0

func GenerateKeyPair() (sk SecretKey, pk PublicKey)

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

func GenerateKeyPairDeterministic added in v1.0.0

func GenerateKeyPairDeterministic(entropy [EntropySize]byte) (sk SecretKey, pk PublicKey)

GenerateKeyPairDeterministic generates keys deterministically using the input entropy. The input entropy must be 32 bytes in length.

func NewHash added in v0.3.0

func NewHash() hash.Hash

NewHash returns a blake2b 256bit hasher.

func ReadSignedObject added in v1.0.0

func ReadSignedObject(r io.Reader, obj interface{}, maxLen uint64, pk PublicKey) error

ReadSignedObject reads a length-prefixed object prefixed by its signature, and verifies the signature.

func SecureWipe added in v1.0.0

func SecureWipe(data []byte)

SecureWipe destroys the data contained within a byte slice. There are no strong guarantees that all copies of the memory have been eliminated. If the OS was doing context switching or using swap space the keys may still be elsewhere in memory.

func VerifyHash added in v0.3.0

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

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

func VerifySegment added in v0.3.0

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

VerifySegment will verify that a segment, given the proof, is a part of a Merkle root.

func WriteSignedObject added in v1.0.0

func WriteSignedObject(w io.Writer, obj interface{}, sk SecretKey) error

WriteSignedObject writes a length-prefixed object prefixed by its signature.

Types

type CachedMerkleTree added in v1.0.0

type CachedMerkleTree struct {
	merkletree.CachedTree
}

CachedMerkleTree wraps merkletree.CachedTree, changing some of the function definitions to assume sia-specific constants and return sia-specific types.

func NewCachedTree added in v1.0.0

func NewCachedTree(height uint64) *CachedMerkleTree

NewCachedTree returns a CachedMerkleTree, which can be used for getting Merkle roots and proofs from data that has cached subroots. See merkletree.CachedTree for more details.

func (*CachedMerkleTree) Prove added in v1.0.0

func (ct *CachedMerkleTree) Prove(base []byte, cachedHashSet []Hash) []Hash

Prove is a redefinition of merkletree.CachedTree.Prove, so that Sia-specific types are used instead of the generic types used by the parent package. The base is not a return value because the base is used as input.

func (*CachedMerkleTree) Push added in v1.0.0

func (ct *CachedMerkleTree) Push(h Hash)

Push is a redefinition of merkletree.CachedTree.Push, with the added type safety of only accepting a hash.

func (*CachedMerkleTree) PushSubTree added in v1.3.3

func (ct *CachedMerkleTree) PushSubTree(height int, h Hash) error

PushSubTree is a redefinition of merkletree.CachedTree.PushSubTree, with the added type safety of only accepting a hash.

func (*CachedMerkleTree) Root added in v1.0.0

func (ct *CachedMerkleTree) Root() (h Hash)

Root is a redefinition of merkletree.CachedTree.Root, returning a Hash instead of a []byte.

type Ciphertext added in v0.3.1

type Ciphertext []byte

Ciphertext is an encrypted []byte.

func (Ciphertext) MarshalJSON added in v1.0.0

func (c Ciphertext) MarshalJSON() ([]byte, error)

MarshalJSON returns the JSON encoding of a CipherText

func (*Ciphertext) UnmarshalJSON added in v1.0.0

func (c *Ciphertext) UnmarshalJSON(b []byte) error

UnmarshalJSON parses the JSON-encoded b and returns an instance of CipherText.

type Hash added in v0.3.0

type Hash [HashSize]byte

Hash is a BLAKE2b 256-bit digest.

func HashAll added in v0.3.0

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

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

func HashBytes added in v0.3.0

func HashBytes(data []byte) Hash

HashBytes takes a byte slice and returns the result.

func HashObject added in v0.3.0

func HashObject(obj interface{}) (hash Hash)

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

func MerkleProof added in v1.0.0

func MerkleProof(b []byte, proofIndex uint64) (base []byte, hashSet []Hash)

MerkleProof builds a Merkle proof that the data at segment 'proofIndex' is a part of the Merkle root formed by 'b'.

func MerkleRoot added in v0.3.0

func MerkleRoot(b []byte) Hash

MerkleRoot returns the Merkle root of the input data.

func (*Hash) LoadString added in v1.0.1

func (h *Hash) LoadString(s string) error

LoadString takes a string, parses the hash value of the string, and sets the value of the hash equal to the hash value of the string.

func (Hash) MarshalJSON added in v1.0.0

func (h Hash) MarshalJSON() ([]byte, error)

MarshalJSON marshales a hash as a hex string.

func (Hash) String added in v1.0.0

func (h Hash) String() string

String prints the hash in hex.

func (*Hash) UnmarshalJSON added in v1.0.0

func (h *Hash) UnmarshalJSON(b []byte) error

UnmarshalJSON decodes the json hex string of the hash.

type HashSlice added in v0.3.0

type HashSlice []Hash

HashSlice is used for sorting

func (HashSlice) Len added in v0.3.0

func (hs HashSlice) Len() int

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

func (HashSlice) Less added in v0.3.0

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

func (HashSlice) Swap added in v0.3.0

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

type MerkleTree added in v1.0.0

type MerkleTree struct {
	merkletree.Tree
}

MerkleTree wraps merkletree.Tree, changing some of the function definitions to assume sia-specific constants and return sia-specific types.

func NewTree added in v0.3.0

func NewTree() *MerkleTree

NewTree returns a MerkleTree, which can be used for getting Merkle roots and Merkle proofs on data. See merkletree.Tree for more details.

func (*MerkleTree) PushObject added in v1.0.0

func (t *MerkleTree) PushObject(obj interface{})

PushObject encodes and adds the hash of the encoded object to the tree as a leaf.

func (*MerkleTree) Root added in v1.0.0

func (t *MerkleTree) Root() (h Hash)

Root is a redefinition of merkletree.Tree.Root, returning a Hash instead of a []byte.

type PublicKey

type PublicKey [PublicKeySize]byte

PublicKey is an object that can be used to verify signatures.

type SecretKey

type SecretKey [SecretKeySize]byte

SecretKey can be used to sign data for the corresponding public key.

func (SecretKey) PublicKey added in v1.0.0

func (sk SecretKey) PublicKey() (pk PublicKey)

PublicKey returns the public key that corresponds to a secret key.

type Signature

type Signature [SignatureSize]byte

Signature proves that data was signed by the owner of a particular public key's corresponding secret key.

func SignHash added in v0.3.0

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

SignHash signs a message using a secret key.

type TwofishKey added in v0.3.0

type TwofishKey [EntropySize]byte

TwofishKey is a key used for encrypting and decrypting data.

func GenerateTwofishKey added in v0.3.0

func GenerateTwofishKey() (key TwofishKey)

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

func (TwofishKey) DecryptBytes added in v0.3.0

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) DecryptBytesInPlace added in v1.3.4

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

DecryptBytesInPlace decrypts the ciphertext created by EncryptBytes. The nonce is expected to be the first 12 bytes of the ciphertext. DecryptBytesInPlace reuses the memory of ct to be able to operate in-place. This means that ct can't be reused after calling DecryptBytesInPlace.

func (TwofishKey) EncryptBytes added in v0.3.0

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

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

func (TwofishKey) NewCipher added in v0.3.2

func (key TwofishKey) NewCipher() cipher.Block

NewCipher creates a new Twofish cipher from the key.

func (TwofishKey) NewReader added in v0.3.2

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

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

func (TwofishKey) NewWriter added in v0.3.2

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

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

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