diff options
Diffstat (limited to 'vendor/golang.org/x/crypto/ed25519/ed25519.go')
| -rw-r--r-- | vendor/golang.org/x/crypto/ed25519/ed25519.go | 60 |
1 files changed, 48 insertions, 12 deletions
diff --git a/vendor/golang.org/x/crypto/ed25519/ed25519.go b/vendor/golang.org/x/crypto/ed25519/ed25519.go index 16cd385..d6f683b 100644 --- a/vendor/golang.org/x/crypto/ed25519/ed25519.go +++ b/vendor/golang.org/x/crypto/ed25519/ed25519.go @@ -6,7 +6,10 @@ // https://ed25519.cr.yp.to/. // // These functions are also compatible with the “Ed25519” function defined in -// https://tools.ietf.org/html/draft-irtf-cfrg-eddsa-05. +// RFC 8032. However, unlike RFC 8032's formulation, this package's private key +// representation includes a public key suffix to make multiple signing +// operations with the same key more efficient. This package refers to the RFC +// 8032 private key as the “seed”. package ed25519 // This code is a port of the public domain, “ref10” implementation of ed25519 @@ -31,6 +34,8 @@ const ( PrivateKeySize = 64 // SignatureSize is the size, in bytes, of signatures generated and verified by this package. SignatureSize = 64 + // SeedSize is the size, in bytes, of private key seeds. These are the private key representations used by RFC 8032. + SeedSize = 32 ) // PublicKey is the type of Ed25519 public keys. @@ -46,6 +51,15 @@ func (priv PrivateKey) Public() crypto.PublicKey { return PublicKey(publicKey) } +// Seed returns the private key seed corresponding to priv. It is provided for +// interoperability with RFC 8032. RFC 8032's private keys correspond to seeds +// in this package. +func (priv PrivateKey) Seed() []byte { + seed := make([]byte, SeedSize) + copy(seed, priv[:32]) + return seed +} + // Sign signs the given message with priv. // Ed25519 performs two passes over messages to be signed and therefore cannot // handle pre-hashed messages. Thus opts.HashFunc() must return zero to @@ -61,19 +75,33 @@ func (priv PrivateKey) Sign(rand io.Reader, message []byte, opts crypto.SignerOp // GenerateKey generates a public/private key pair using entropy from rand. // If rand is nil, crypto/rand.Reader will be used. -func GenerateKey(rand io.Reader) (publicKey PublicKey, privateKey PrivateKey, err error) { +func GenerateKey(rand io.Reader) (PublicKey, PrivateKey, error) { if rand == nil { rand = cryptorand.Reader } - privateKey = make([]byte, PrivateKeySize) - publicKey = make([]byte, PublicKeySize) - _, err = io.ReadFull(rand, privateKey[:32]) - if err != nil { + seed := make([]byte, SeedSize) + if _, err := io.ReadFull(rand, seed); err != nil { return nil, nil, err } - digest := sha512.Sum512(privateKey[:32]) + privateKey := NewKeyFromSeed(seed) + publicKey := make([]byte, PublicKeySize) + copy(publicKey, privateKey[32:]) + + return publicKey, privateKey, nil +} + +// NewKeyFromSeed calculates a private key from a seed. It will panic if +// len(seed) is not SeedSize. This function is provided for interoperability +// with RFC 8032. RFC 8032's private keys correspond to seeds in this +// package. +func NewKeyFromSeed(seed []byte) PrivateKey { + if l := len(seed); l != SeedSize { + panic("ed25519: bad seed length: " + strconv.Itoa(l)) + } + + digest := sha512.Sum512(seed) digest[0] &= 248 digest[31] &= 127 digest[31] |= 64 @@ -85,10 +113,11 @@ func GenerateKey(rand io.Reader) (publicKey PublicKey, privateKey PrivateKey, er var publicKeyBytes [32]byte A.ToBytes(&publicKeyBytes) + privateKey := make([]byte, PrivateKeySize) + copy(privateKey, seed) copy(privateKey[32:], publicKeyBytes[:]) - copy(publicKey, publicKeyBytes[:]) - return publicKey, privateKey, nil + return privateKey } // Sign signs the message with privateKey and returns a signature. It will @@ -171,9 +200,16 @@ func Verify(publicKey PublicKey, message, sig []byte) bool { edwards25519.ScReduce(&hReduced, &digest) var R edwards25519.ProjectiveGroupElement - var b [32]byte - copy(b[:], sig[32:]) - edwards25519.GeDoubleScalarMultVartime(&R, &hReduced, &A, &b) + var s [32]byte + copy(s[:], sig[32:]) + + // https://tools.ietf.org/html/rfc8032#section-5.1.7 requires that s be in + // the range [0, order) in order to prevent signature malleability. + if !edwards25519.ScMinimal(&s) { + return false + } + + edwards25519.GeDoubleScalarMultVartime(&R, &hReduced, &A, &s) var checkR [32]byte R.ToBytes(&checkR) |