crypto

package
v0.2.3 Latest Latest
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 Go to latest Published: Dec 11, 2018 License: MIT Imports: 17 Imported by: 22

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

	// CurvePointSize defines the size of a curve point in bytes.
	CurvePointSize = ed25519.CurvePointSize
)
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
)

Variables

View Source 
var (
	// TypeDefaultRenter is the default CipherType that is used for
	// encrypting pieces of uploaded data.
	TypeDefaultRenter = TypeThreefish
	// TypeDefaultWallet is the default CipherType that is used for
	// wallet operations like encrypting the wallet files.
	TypeDefaultWallet = TypeTwofish

	// TypePlain means no encryption is used.
	TypePlain = CipherType{0, 0, 0, 0, 0, 0, 0, 1}
	// TypeTwofish is the type for the Twofish-GCM encryption.
	TypeTwofish = CipherType{0, 0, 0, 0, 0, 0, 0, 2}
	// TypeThreefish is the type for the Threefish encryption.
	TypeThreefish = CipherType{0, 0, 0, 0, 0, 0, 0, 3}
)
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")

	// ErrCurvePointWrongLen is the error when encoded value has the wrong length to
	// be a curve point
	ErrCurvePointWrongLen = errors.New("encoded value has the wrong length to be a curve point")
)
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 (
	// ErrInvalidCipherType is returned upon encountering an unknown cipher
	// type.
	ErrInvalidCipherType = errors.New("provided cipher type is invalid")
)

Functions

func CalculateLeaves 

func CalculateLeaves(dataSize uint64) uint64

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

func GenerateKeyPair 

func GenerateKeyPair() (sk SecretKey, pk PublicKey)

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

func GenerateKeyPairDeterministic 

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 IsValidCipherType 

func IsValidCipherType(ct CipherType) bool

IsValidCipherType returns true if ct is a known CipherType and false otherwise.

func NewHash 

func NewHash() hash.Hash

NewHash returns a blake2b 256bit hasher.

func ReadSignedObject 

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 

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 

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

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

func VerifySegment 

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 

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

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

Types

type CachedMerkleTree 

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 

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 

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 

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 

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 

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

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

type CipherKey 

type CipherKey interface {
	// Key returns the underlying key.
	Key() []byte

	// Type returns the type of the key.
	Type() CipherType

	// EncryptBytes encrypts the given plaintext and returns the
	// ciphertext.
	EncryptBytes([]byte) Ciphertext

	// DecryptBytes decrypts the given ciphertext and returns the
	// plaintext.
	DecryptBytes(Ciphertext) ([]byte, error)

	// DecryptBytesInPlace decrypts the given ciphertext and returns the
	// plaintext. It will reuse the memory of the ciphertext which means
	// that it's not save to use it after calling DecryptBytesInPlace.
	DecryptBytesInPlace(Ciphertext) ([]byte, error)

	// Derive derives a child cipherkey given a provided chunk index and
	// piece index.
	Derive(chunkIndex, pieceIndex uint64) CipherKey
}

CipherKey is a key with Sia specific encryption/decryption methods.

func GenerateSiaKey 

func GenerateSiaKey(ct CipherType) CipherKey

GenerateSiaKey creates a new SiaKey from the provided type and entropy.

func NewSiaKey 

func NewSiaKey(ct CipherType, entropy []byte) (CipherKey, error)

NewSiaKey creates a new SiaKey from the provided type and entropy.

func NewWalletKey 

func NewWalletKey(entropy Hash) CipherKey

NewWalletKey is a helper method which is meant to be used only if the type and entropy are guaranteed to be valid. In the wallet this is always the case since we always use hashes as the entropy and we don't read the key from file.

type CipherType 

type CipherType [8]byte

CipherType is an identifier for the individual ciphers provided by this package.

func RandomCipherType 

func RandomCipherType() CipherType

RandomCipherType is a helper function for testing. It's located in the crypto package to centralize all the types within one file to make future changes to them easy.

func (*CipherType) FromString 

func (ct *CipherType) FromString(s string) error

FromString reads a CipherType from a string.

func (CipherType) Overhead 

func (ct CipherType) Overhead() uint64

Overhead reports the overhead produced by a CipherType in bytes.

func (CipherType) String 

func (ct CipherType) String() string

String creates a string representation of a CipherType that can be converted into a type with FromString.

type Ciphertext 

type Ciphertext []byte

Ciphertext is an encrypted []byte.

type CurvePoint 

type CurvePoint [CurvePointSize]byte

CurvePoint represents a point on the elliptic curve.

func (*CurvePoint) LoadString 

func (cp *CurvePoint) LoadString(s string) error

LoadString unmarshal CurvePoint from string

func (*CurvePoint) String 

func (cp *CurvePoint) String() string

type Hash 

type Hash [HashSize]byte

Hash is a BLAKE2b 256-bit digest.

func HashAll 

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 

func HashBytes(data []byte) Hash

HashBytes takes a byte slice and returns the result.

func HashObject 

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 

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 

func MerkleRoot(b []byte) Hash

MerkleRoot returns the Merkle root of the input data.

func (*Hash) LoadString 

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 

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

MarshalJSON marshales a hash as a hex string.

func (Hash) String 

func (h Hash) String() string

String prints the hash in hex.

func (*Hash) UnmarshalJSON 

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

UnmarshalJSON decodes the json hex string of the hash.

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 MerkleTree 

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 

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 

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 

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 

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 

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

SignHash signs a message using a secret key.

Source Files

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