// Generates an RSA private key and computes the corresponding 64-bit
// Id for it, using Id=Fold(Sha256(Rsa64(PublicKey)))
//
// TODO:
// (*) Decide on default signature key size
// (*) Allow custom-size private keys, and/or
func GenerateSigKey() *SigKey {
randr := crypto.NewTimedRand()
rsapriv, err := rsa.GenerateKey(randr, SignatureModulusLen*8)
if err != nil {
panic("unable to generate RSA key")
}
return &SigKey{rsapriv}
}
func GenerateSigChallange() []byte {
urand := crypto.NewTimedRand()
ch := make([]byte, 20) // we are using SHA1 hash for RSA signature
n, err := urand.Read(ch)
if err != nil || n != len(ch) {
panic("sys, chall")
}
return ch
}
func GenerateKeyHalves() *KeyHalves {
urand := crypto.NewTimedRand()
kh := &KeyHalves{}
kh.bothKeys = make([]byte, KeyHalvesLen)
n, _ := urand.Read(kh.bothKeys)
if n != len(kh.bothKeys) {
panic("d")
}
return kh
}
func (sk *SigKey) Sign(msg []byte) ([]byte, os.Error) {
// Hash the message
hash := sha1.New()
n, err := hash.Write(msg)
if err != nil || n != len(msg) {
return nil, err
}
hashed := hash.Sum()
// Sign the message
urand := crypto.NewTimedRand()
s, err := rsa.SignPKCS1v15(urand, sk.RsaPrivKey(), rsa.HashSHA1, hashed)
if err != nil {
return nil, err
}
return s, nil
}
func GenerateDialKey() *DialKey {
rand := crypto.NewTimedRand()
dk := DialKey(rand.Int63())
return &dk
}