app: restructure and start building p15 output

pkg/pkcs15/pem_to_p15.go

@@ -0,0 +1,36 @@
+package pkcs15
+
+import (
+	"crypto/rsa"
+	"crypto/x509"
+)
+
+// pkcs15KeyCert holds the data for a key and certificate pair; it provides
+// various methods to transform pkcs15 data
+type pkcs15KeyCert struct {
+	key  *rsa.PrivateKey
+	cert *x509.Certificate
+}
+
+// ParsePEMToPKCS15 parses the provide pem files to a pkcs15 struct; it also does some
+// basic sanity check; if any of this fails, an error is returned
+func ParsePEMToPKCS15(keyPem, certPem []byte) (*pkcs15KeyCert, error) {
+	// decode / check key
+	key, err := pemKeyDecode(keyPem)
+	if err != nil {
+		return nil, err
+	}
+
+	// decode / check cert
+	cert, err := pemCertDecode(certPem, keyPem)
+	if err != nil {
+		return nil, err
+	}
+
+	p15 := &pkcs15KeyCert{
+		key:  key,
+		cert: cert,
+	}
+
+	return p15, nil
+}