going somewhere

contract/contract_generators.go

@@ -0,0 +1,98 @@
+package contract
+
+import (
+	"crypto/rand"
+	"crypto/rsa"
+	"encoding/json"
+	"errors"
+	"os"
+	"path"
+
+	"github.com/didiercrunch/filou/keys"
+	"github.com/didiercrunch/filou/shared"
+)
+
+type ContractsGenerator struct {
+	publicKey  *keys.RSAPublicKey
+	privateKey *keys.RSAPrivateKey
+
+	privateContract *PrivateContract
+	publicContract  *PublicContract
+}
+
+func (this *ContractsGenerator) ensureDirectoryExists(dir string) error {
+	stat, err := os.Stat(dir)
+	if os.IsNotExist(err) {
+		return os.Mkdir(dir, 0700)
+	} else if err != nil {
+		return err
+	} else if !stat.IsDir() {
+		return errors.New(dir + " is not a directory")
+	}
+	return nil
+}
+
+func (this *ContractsGenerator) saveContractAsJSON(contract interface{}, filepath string) error {
+	w, err := os.Create(filepath)
+	if err != nil {
+		return err
+	}
+	enc := json.NewEncoder(w)
+	return enc.Encode(contract)
+}
+
+func (this *ContractsGenerator) saveContracts(dirPath string) error {
+	if err := this.ensureDirectoryExists(dirPath); err != nil {
+		return err
+	}
+	if err := this.saveContractAsJSON(this.publicContract, path.Join(dirPath, "public_contract.json")); err != nil {
+		return err
+	}
+	return this.saveContractAsJSON(this.privateContract, path.Join(dirPath, "private_contract.json"))
+}
+
+func (this *ContractsGenerator) createRSAKeys(size int) error {
+	rsaPrivateKey, err := rsa.GenerateKey(rand.Reader, size)
+	if err != nil {
+		return errors.New("cannot generate the rsa public/private key pair\n" + err.Error())
+	}
+
+	this.privateKey = keys.NewRSAPrivateKey(rsaPrivateKey)
+	this.publicKey = keys.NewRSAPublicKey(&rsaPrivateKey.PublicKey)
+	return nil
+}
+
+func (this *ContractsGenerator) createPrivateContractWithGoodDefaultValues(key *keys.RSAPrivateKey) {
+	this.privateContract = new(PrivateContract)
+	this.privateContract.AcceptedAsynchronousEncryptionScheme = []string{"rsa_oaep"}
+	this.privateContract.AcceptedSignatureScheme = []string{"rsa_pss"}
+	this.privateContract.AcceptedBlockCypherModes = []string{"ofb"}
+	this.privateContract.AcceptedBlockCyphers = []string{"aes"}
+	this.privateContract.RSAPrivateKey = []*keys.RSAPrivateKey{key}
+	this.privateContract.RSAPublicKey = []*keys.RSAPublicKey{}
+}
+
+func (this *ContractsGenerator) createPublicContractWithGoodDefaultValues(key *keys.RSAPublicKey) {
+	this.publicContract = new(PublicContract)
+	this.privateContract.AcceptedAsynchronousEncryptionScheme = []string{"rsa_oaep"}
+	this.privateContract.AcceptedSignatureScheme = []string{"rsa_pss"}
+	this.privateContract.AcceptedBlockCypherModes = []string{"ofb"}
+	this.privateContract.AcceptedBlockCyphers = []string{"aes"}
+	this.privateContract.RSAPublicKey = []*keys.RSAPublicKey{key}
+}
+
+func (this *ContractsGenerator) createContracts(keySize int) error {
+	if err := this.createRSAKeys(keySize); err != nil {
+		return err
+	}
+	this.createPrivateContractWithGoodDefaultValues(this.privateKey)
+	this.createPublicContractWithGoodDefaultValues(this.publicKey)
+	return nil
+}
+
+func (this *ContractsGenerator) CreateContracts(size int) error {
+	if err := this.createContracts(size); err != nil {
+		return err
+	}
+	return this.saveContracts(shared.GetEcryptoDir())
+}