Exemple #1
1
//VerifySignature verifies the signature of a message
func (rsaKey *RsaKey) VerifySignature(message string, signature string) (err error) {
	hashAlgorithm := crypto.SHA256
	if rsaKey.privateKey == nil {
		err = errors.New("privateKey is nil")
		return
	}
	messageBytes := bytes.NewBufferString(message)

	//hash
	pssh := hashAlgorithm.New()
	pssh.Write(messageBytes.Bytes())
	messageHash := pssh.Sum(nil)

	var signatureBytes []byte
	signatureBytes, err = base64.StdEncoding.DecodeString(signature)
	if err != nil {
		return
	}

	//Verify signature
	var opts rsa.PSSOptions
	opts.SaltLength = rsa.PSSSaltLengthAuto
	err = rsa.VerifyPSS(&rsaKey.privateKey.PublicKey, hashAlgorithm, messageHash, signatureBytes, &opts)

	return
}
Exemple #2
0
func (m *Msg) Message(fromkey *rsa.PublicKey, dstkey *rsa.PrivateKey) (data []byte, err error) {
	hash := crypto.SHA256
	data = make([]byte, 0)
	for i, d := range m.Data {
		plainText, err := rsa.DecryptOAEP(hash.New(), rand.Reader, dstkey, d, []byte(""))
		if err != nil {
			return nil, e.Push(err, "can't decrypt the message")
		}
		pssh := hash.New()
		pssh.Write(plainText)
		hashed := pssh.Sum(nil)
		var opts rsa.PSSOptions
		opts.SaltLength = rsa.PSSSaltLengthAuto
		err = rsa.VerifyPSS(fromkey, hash, hashed, m.Signature[i], &opts)
		if err != nil {
			return nil, e.Push(err, "can't verify the signature")
		}
		data = append(data, plainText...)
	}
	return data, nil
}
Exemple #3
0
func NewMsg(from, to string, fromkey *rsa.PrivateKey, tokey *rsa.PublicKey, data []byte) (*Msg, error) {
	hash := crypto.SHA256
	max := tokey.N.BitLen()/8 - 2*hash.Size() - 2
	num := len(data) / max
	if len(data)%max > 0 {
		num++
	}
	msg := &Msg{
		From:      from,
		To:        to,
		Data:      make([][]byte, num),
		Signature: make([][]byte, num),
	}
	j := 0
	for i := 0; i < len(data); i += max {
		end := i + max
		if end > len(data) {
			end = len(data)
		}

		ciphertex, err := rsa.EncryptOAEP(hash.New(), rand.Reader, tokey, data[i:end], []byte(""))
		if err != nil {
			return nil, e.Push(err, "can't encrypt message")
		}
		pssh := hash.New()
		pssh.Write(data[i:end])
		hashed := pssh.Sum(nil)
		var opts rsa.PSSOptions
		opts.SaltLength = rsa.PSSSaltLengthAuto
		signature, err := rsa.SignPSS(rand.Reader, fromkey, hash, hashed, &opts)
		if err != nil {
			return nil, e.Push(err, "can't sign the message")
		}
		msg.Data[j] = ciphertex
		msg.Signature[j] = signature
		j++
	}

	return msg, nil
}
Exemple #4
0
//Sign creates the signature for a message
func (rsaKey *RsaKey) Sign(message string) (signature string, err error) {
	var signatureBytes []byte
	hashAlgorithm := crypto.SHA256

	messageBytes := bytes.NewBufferString(message)

	//hash
	hasher := hashAlgorithm.New()
	hasher.Write(messageBytes.Bytes())
	messageHash := hasher.Sum(nil)

	//sign
	var pssOptions rsa.PSSOptions
	pssOptions.SaltLength = saltSize
	pssOptions.Hash = hashAlgorithm
	signatureBytes, err = rsa.SignPSS(rand.Reader, rsaKey.privateKey, hashAlgorithm, messageHash, &pssOptions)
	if err != nil {
		return
	}
	signature = base64.StdEncoding.EncodeToString(signatureBytes)

	return
}
func main() {

	// Generate RSA Keys
	miryanPrivateKey, err := rsa.GenerateKey(rand.Reader, 2048)

	if err != nil {
		fmt.Println(err.Error)
		os.Exit(1)
	}

	miryanPublicKey := &miryanPrivateKey.PublicKey

	raulPrivateKey, err := rsa.GenerateKey(rand.Reader, 2048)

	if err != nil {
		fmt.Println(err.Error)
		os.Exit(1)
	}

	raulPublicKey := &raulPrivateKey.PublicKey

	fmt.Println("Private Key : ", miryanPrivateKey)
	fmt.Println("Public key ", miryanPublicKey)
	fmt.Println("Private Key : ", raulPrivateKey)
	fmt.Println("Public key ", raulPublicKey)

	//Encrypt Miryan Message
	message := []byte("the code must be like a piece of music")
	label := []byte("")
	hash := sha256.New()

	ciphertext, err := rsa.EncryptOAEP(hash, rand.Reader, raulPublicKey, message, label)

	if err != nil {
		fmt.Println(err)
		os.Exit(1)
	}

	fmt.Printf("OAEP encrypted [%s] to \n[%x]\n", string(message), ciphertext)
	fmt.Println()

	// Message - Signature
	var opts rsa.PSSOptions
	opts.SaltLength = rsa.PSSSaltLengthAuto // for simple example
	PSSmessage := message
	newhash := crypto.SHA256
	pssh := newhash.New()
	pssh.Write(PSSmessage)
	hashed := pssh.Sum(nil)

	signature, err := rsa.SignPSS(rand.Reader, miryanPrivateKey, newhash, hashed, &opts)

	if err != nil {
		fmt.Println(err)
		os.Exit(1)
	}

	fmt.Printf("PSS Signature : %x\n", signature)

	// Decrypt Message
	plainText, err := rsa.DecryptOAEP(hash, rand.Reader, raulPrivateKey, ciphertext, label)

	if err != nil {
		fmt.Println(err)
		os.Exit(1)
	}

	fmt.Printf("OAEP decrypted [%x] to \n[%s]\n", ciphertext, plainText)

	//Verify Signature
	err = rsa.VerifyPSS(miryanPublicKey, newhash, hashed, signature, &opts)

	if err != nil {
		fmt.Println("Who are U? Verify Signature failed")
		os.Exit(1)
	} else {
		fmt.Println("Verify Signature successful")
	}

}