module ed25519 import crypto.rand import crypto.sha512 import crypto.internal.subtle import crypto.ed25519.internal.edwards25519 // public_key_size is the sizeof public keys in bytes pub const public_key_size = 32 // private_key_size is the sizeof private keys in bytes pub const private_key_size = 64 // signature_size is the size of signatures generated and verified by this modules, in bytes. pub const signature_size = 64 // seed_size is the size of private key seeds in bytes pub const seed_size = 32 // `PublicKey` is Ed25519 public keys. pub type PublicKey = []byte // equal reports whether p and x have the same value. pub fn (p PublicKey) equal(x []byte) bool { return subtle.constant_time_compare(p, PublicKey(x)) == 1 } // PrivateKey is Ed25519 private keys pub type PrivateKey = []byte // seed returns the private key seed corresponding to priv. // RFC 8032's private keys correspond to seeds in this module. pub fn (priv PrivateKey) seed() []byte { mut seed := []byte{len: ed25519.seed_size} copy(mut seed, priv[..32]) return seed } // public_key returns the []byte corresponding to priv. pub fn (priv PrivateKey) public_key() PublicKey { assert priv.len == ed25519.private_key_size mut publickey := []byte{len: ed25519.public_key_size} copy(mut publickey, priv[32..]) return PublicKey(publickey) } // currentyly x not `crypto.PrivateKey` pub fn (priv PrivateKey) equal(x []byte) bool { return subtle.constant_time_compare(priv, PrivateKey(x)) == 1 } // sign signs the given message with priv. pub fn (priv PrivateKey) sign(message []byte) ?[]byte { /* if opts.HashFunc() != crypto.Hash(0) { return nil, errors.New("ed25519: cannot sign hashed message") }*/ return sign(priv, message) } // sign`signs the message with privatekey and returns a signature pub fn sign(privatekey PrivateKey, message []byte) ?[]byte { mut signature := []byte{len: ed25519.signature_size} sign_generic(mut signature, privatekey, message) ? return signature } fn sign_generic(mut signature []byte, privatekey []byte, message []byte) ? { if privatekey.len != ed25519.private_key_size { panic('ed25519: bad private key length: $privatekey.len') } seed, publickey := privatekey[..ed25519.seed_size], privatekey[ed25519.seed_size..] mut h := sha512.sum512(seed) mut s := edwards25519.new_scalar() s.set_bytes_with_clamping(h[..32]) ? mut prefix := h[32..] mut mh := sha512.new() mh.write(prefix) ? mh.write(message) ? mut msg_digest := []byte{cap: sha512.size} msg_digest = mh.sum(msg_digest) mut r := edwards25519.new_scalar() r.set_uniform_bytes(msg_digest) ? mut rr := edwards25519.Point{} rr.scalar_base_mult(mut r) mut kh := sha512.new() kh.write(rr.bytes()) ? kh.write(publickey) ? kh.write(message) ? mut hram_digest := []byte{cap: sha512.size} hram_digest = kh.sum(hram_digest) mut k := edwards25519.new_scalar() k.set_uniform_bytes(hram_digest) ? mut ss := edwards25519.new_scalar() ss.multiply_add(k, s, r) copy(mut signature[..32], rr.bytes()) copy(mut signature[32..], ss.bytes()) } // verify reports whether sig is a valid signature of message by publickey. pub fn verify(publickey PublicKey, message []byte, sig []byte) ?bool { if publickey.len != ed25519.public_key_size { return error('ed25519: bad public key length: $publickey.len') } if sig.len != ed25519.signature_size || sig[63] & 224 != 0 { return false } mut aa := edwards25519.Point{} aa.set_bytes(publickey) ? mut kh := sha512.new() kh.write(sig[..32]) ? kh.write(publickey) ? kh.write(message) ? mut hram_digest := []byte{cap: sha512.size} hram_digest = kh.sum(hram_digest) mut k := edwards25519.new_scalar() k.set_uniform_bytes(hram_digest) ? mut ss := edwards25519.new_scalar() ss.set_canonical_bytes(sig[32..]) ? // [S]B = R + [k]A --> [k](-A) + [S]B = R mut minus_a := edwards25519.Point{} minus_a.negate(aa) mut rr := edwards25519.Point{} rr.vartime_double_scalar_base_mult(k, minus_a, ss) return subtle.constant_time_compare(sig[..32], rr.bytes()) == 1 } // generate_key generates a public/private key pair entropy using `crypto.rand`. pub fn generate_key() ?(PublicKey, PrivateKey) { mut seed := rand.bytes(ed25519.seed_size) ? privatekey := new_key_from_seed(seed) mut publickey := []byte{len: ed25519.public_key_size} copy(mut publickey, privatekey[32..]) return publickey, privatekey } // new_key_from_seed calculates a private key from a seed. private keys of RFC 8032 // correspond to seeds in this module pub fn new_key_from_seed(seed []byte) PrivateKey { // Outline the function body so that the returned key can be stack-allocated. mut privatekey := []byte{len: ed25519.private_key_size} new_key_from_seed_generic(mut privatekey, seed) return PrivateKey(privatekey) } fn new_key_from_seed_generic(mut privatekey []byte, seed []byte) { if seed.len != ed25519.seed_size { panic('ed25519: bad seed length: $seed.len') } mut h := sha512.sum512(seed) mut s := edwards25519.new_scalar() s.set_bytes_with_clamping(h[..32]) or { panic(err) } mut aa := edwards25519.Point{} aa.scalar_base_mult(mut s) mut publickey := aa.bytes() copy(mut privatekey, seed) copy(mut privatekey[32..], publickey) }