going somewhere

asymetric/constructor.go

@@ -1,7 +1,11 @@
 package asymetric
 
 import (
+	"crypto/rand"
+	"errors"
+
 	"github.com/didiercrunch/filou/contract"
+	"github.com/didiercrunch/filou/helper"
 )
 
 type PublicKeyEncryptor interface {
@@ -12,10 +16,37 @@ type Signer interface {
 	Sign(data []byte) ([]byte, error)
 }
 
-func GetSigner(contract_ contract.AcceptedContract) (Signer, error) {
-	return nil, nil
+func GetSigner(contract_ *contract.AcceptedContract) (Signer, error) {
+	if contract_.SignatureScheme == "rsa_pss" {
+		return getRsaPssSignerFromContract(contract_)
+	}
+	return nil, errors.New("signature scheme " + contract_.SignatureScheme + " not supported")
 }
 
-func GetPublicKeyEncryptor(contract_ contract.AcceptedContract) (Signer, error) {
-	return nil, nil
+func GetPublicKeyEncryptor(contract_ *contract.AcceptedContract) (PublicKeyEncryptor, error) {
+	if contract_.AsynchronousEncryptionScheme == "rsa_oaep" {
+		return getRsaOaepEncryptorFromContract(contract_)
+	} else {
+		return nil, errors.New("asynchronous encryption scheme " + contract_.AsynchronousEncryptionScheme + " not supported")
+	}
+}
+
+func getRsaPssSignerFromContract(con *contract.AcceptedContract) (*RsaPssSigner, error) {
+	if privKey, err := con.RsaPrivateKey(); err != nil {
+		return nil, err
+	} else if hash, err := helper.GetHashFunctionByLowerCaseName(con.Hash); err != nil {
+		return nil, err
+	} else {
+		return &RsaPssSigner{privKey, con.RsaPublicKey, hash, rand.Reader}, nil
+	}
+}
+
+func getRsaOaepEncryptorFromContract(con *contract.AcceptedContract) (*RsaOaepEncrypter, error) {
+	if privKey, err := con.RsaPrivateKey(); err != nil {
+		return nil, err
+	} else if hash, err := helper.GetHashFunctionByLowerCaseName(con.Hash); err != nil {
+		return nil, err
+	} else {
+		return &RsaOaepEncrypter{privKey, con.RsaPublicKey, hash, rand.Reader}, nil
+	}
 }