README
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Unique Ring Signatures (URS)
URS can be used to sign plaintext or binaries anonymously (among a group of known users). That is a user can sign a message, hiding among a group of known/registered users, that prevents the verifier from revealing the signer's identity other than knowing that it is in the set of registered users. The size of the set of registered users is flexible. Increasing this number slows down signing and verifying linearly, and also increases the size of the signatures linearly.
Bitcoin public and private keys are used to generate the signatures. You may generate your own keypairs with the set-generate function described below. Bitcoin addresses are also generated.
When in default (unique) mode, signatures are generated with the prefix '1' and contain immutable Hx, Hy values as the first two bigints in the signature. These are immutable per message and private key. That is, any single message signed with the same private key and keyring will always generate the same Hx, Hy values, so for this single message you can identify if multiple members of the keyring have signed (but not which one).
Signature blinding has also been implemented. Blind signatures are prefixed with '2'. While blind signatures lose their Hx, Hy uniqueness, they use an ephemeral key to generate that signature that is afterwards discarded. This will prevents someone in the future from being able to identify which member of the ring signaturesigned the message, even if all private keys for the public keys in the keyring are later revealed.
For more information on signature blinding, refer to this link.
Requirements
Go 1.11 or newer.
Usage
import "github.com/Cealgull/urs"
Acknowledgements
Documentation
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Overview ¶
Package urs implements Unique Ring Signatures, as defined in short version: http://csiflabs.cs.ucdavis.edu/~hbzhang/romring.pdf full version: http://eprint.iacr.org/2012/577.pdf
Index ¶
- func Base582Hex(b string) []byte
- func BlindVerify(R *PublicKeyRing, m []byte, rs *BlindRingSign) bool
- func CmpPubKey(i, j *ecdsa.PublicKey) bool
- func GenerateKey(c elliptic.Curve, rand io.Reader) (priv *ecdsa.PrivateKey, err error)
- func GetBinaryFileData(filename string) ([]byte, error)
- func GetSigFileData(filename string) ([]byte, error)
- func GetTextFileData(filename string) ([]byte, error)
- func Hex2Base58Str(val []byte) string
- func Hex2Base58String(val []byte) string
- func Hex2Big(b []byte) *big.Int
- func PubKeyToString(k ecdsa.PublicKey) string
- func ReadKeyPair(filename string) (*ecdsa.PrivateKey, error)
- func String2Hex(s string) []byte
- func StripTextFile(b []byte) []byte
- func TestBase58()
- func Verify(R *PublicKeyRing, m []byte, rs *RingSign) bool
- type Base58
- type BlindRingSign
- type PublicKeyRing
- type RingSign
Constants ¶
This section is empty.
Variables ¶
This section is empty.
Functions ¶
func BlindVerify ¶
func BlindVerify(R *PublicKeyRing, m []byte, rs *BlindRingSign) bool
BlindVerify verifies the signature in rs of m using the public key ring, R. Its return value records whether the signature is valid.
func CmpPubKey ¶
CmpPubKey compares two pubkeys and returns true if they are the same, else false. WARNING: Assumes the curves are equivalent!
func GenerateKey ¶
GenerateKey generates a public and private key pair.
func GetBinaryFileData ¶
GetBinaryFileData retrieves the []byte encoding of a binary file from a path. It hashes the data it obtains sequentially to compress the file.
func GetSigFileData ¶
GetSigFileData retrieves the []byte encoding of a signature file from a path.
func GetTextFileData ¶
GetTextFileData retrieves the []byte encoding of a text file from a path.
func Hex2Base58Str ¶
func Hex2Base58String ¶
func PubKeyToString ¶
func ReadKeyPair ¶
func ReadKeyPair(filename string) (*ecdsa.PrivateKey, error)
ReadKeyPair reads an ECDSA keypair a file in JSON object format. Example JSON input:
{
"privkey": "..."
}
It also checks if a pubkey is in the keyring and, if not, appends it to the keyring.
func String2Hex ¶
func StripTextFile ¶
StripTextFile removes line breaks from a text file to ensure that signatures of text files function correctly cross platform.
Types ¶
type Base58 ¶
type Base58 string
type to hold the Base58 string
func StrHex2Base58 ¶
func String2Base58 ¶
func StringHex2Base58 ¶
encodes string stored hex bytes into base58
func (Base58) Base582Big ¶
type BlindRingSign ¶
type BlindRingSign struct {
KX, KY *big.Int
X, Y *big.Int
C, T []*big.Int
// contains filtered or unexported fields
}
func BlindSign ¶
func BlindSign(rand io.Reader, priv *ecdsa.PrivateKey, R *PublicKeyRing, m []byte) (rs *BlindRingSign, err error)
BlindSign signs an arbitrary length message (which should NOT be the hash of a larger message) using the private key, priv and the public key ring, R. It returns the signature as a struct of type RingSign. The security of the private key depends on the entropy of rand. The public keys in the ring must all be using the same curve.
func (*BlindRingSign) FromBase58 ¶
func (k *BlindRingSign) FromBase58(sig string) error
FromBase58 returns a ring signature from a Base58 string, to the RingSign struct.
func (*BlindRingSign) ToBase58 ¶
func (k *BlindRingSign) ToBase58() string
ToBase58 returns a ring signature as a Base58 string.
type PublicKeyRing ¶
PublicKeyRing is a list of public keys.
func NewPublicKeyRing ¶
func NewPublicKeyRing(cap uint) *PublicKeyRing
NewPublicKeyRing creates a new public key ring. All keys added to the ring must use the same curve.
func ReadKeyRing ¶
func ReadKeyRing(filename string, kp *ecdsa.PrivateKey) (*PublicKeyRing, error)
ReadKeyRing reads a key ring of public keys from a file in JSON object format, and also inserts the pubkey of a keypair if it's not already present (handles bug in URS implementation).
func (*PublicKeyRing) Add ¶
func (r *PublicKeyRing) Add(pub ecdsa.PublicKey)
Add adds a public key, pub to the ring. All keys added to the ring must use the same curve.
func (*PublicKeyRing) Bytes ¶
func (r *PublicKeyRing) Bytes() (b []byte)
Bytes returns the public key ring as a byte slice.
func (*PublicKeyRing) Less ¶
func (r *PublicKeyRing) Less(i, j int) bool
Less determines which of two []ecdsa.PublicKey X values is smaller; if they are the same, evaluate the Y values instead.
func (*PublicKeyRing) Swap ¶
func (r *PublicKeyRing) Swap(i, j int)
Swap swaps two []ecdsa.PublicKey values.
type RingSign ¶
func Sign ¶
func Sign(rand io.Reader, priv *ecdsa.PrivateKey, R *PublicKeyRing, m []byte) (rs *RingSign, err error)
Sign signs an arbitrary length message (which should NOT be the hash of a larger message) using the private key, priv and the public key ring, R. It returns the signature as a struct of type RingSign. The security of the private key depends on the entropy of rand. The public keys in the ring must all be using the same curve.
func (*RingSign) FromBase58 ¶
FromBase58 returns a ring signature from a Base58 string, to the RingSign struct.
Source Files