get rid of stdi2p package, move everything relivent to common package

lib/common/certificate.go

@@ -0,0 +1,92 @@
+package common
+
+import (
+	"encoding/binary"
+	"github.com/bounce-chat/go-i2p/lib/crypto"
+)
+
+const (
+	CERT_NULL = iota
+	CERT_HASHCASH
+	CERT_HIDDEN
+	CERT_SIGNED
+	CERT_MULTIPLE
+	CERT_KEY
+)
+
+const (
+	KEYCERT_SIGN_DSA_SHA1 = iota
+	KEYCERT_SIGN_P256
+	KEYCERT_SIGN_P384
+	KEYCERT_SIGN_P521
+	KEYCERT_SIGN_RSA2048
+	KEYCERT_SIGN_RSA3072
+	KEYCERT_SIGN_RSA4096
+	KEYCERT_SIGN_ED25519
+)
+
+const (
+	KEYCERT_CRYPTO_ELG = iota
+)
+
+// used to append data to existing data structures
+type Certificate []byte
+
+// return the type of this certificate
+func (c Certificate) Type() byte {
+	return c[0]
+}
+
+// get the length of the data in this certificate
+func (c Certificate) Len() int {
+	return int(binary.BigEndian.Uint16(c[1:3]))
+}
+
+// get the data for this certificate or null if non exists
+func (c Certificate) Data() (d []byte) {
+	l := c.Len()
+	if l > 0 {
+		// TODO(psi): check bounds correctly?
+		d = c[3 : 3+l]
+	}
+	return
+}
+
+// a Certificate of type KEY
+type KeyCert []byte
+
+func (c KeyCert) Type() byte {
+	return Certificate(c).Type()
+}
+
+func (c KeyCert) Data() []byte {
+	return Certificate(c).Data()
+}
+
+// get the signing public key from this key cert
+func (c KeyCert) SigningPublicKey() (k crypto.SigningPublicKey) {
+	data := c.Data()
+	ktype := binary.BigEndian.Uint16(data[:2])
+	// set data to be the key data now
+	data = data[4:]
+	// determine the key type
+	if ktype == KEYCERT_SIGN_DSA_SHA1 {
+		var pk crypto.DSAPublicKey
+		copy(pk[:], data[:pk.Len()])
+		k = pk
+	} else if ktype == KEYCERT_SIGN_P256 {
+		var pk crypto.ECP256PublicKey
+		copy(pk[:], data[:pk.Len()])
+		k = pk
+	} else if ktype == KEYCERT_SIGN_P384 {
+		var pk crypto.ECP384PublicKey
+		copy(pk[:], data[:pk.Len()])
+		k = pk
+	} else if ktype == KEYCERT_SIGN_P521 {
+		var pk crypto.ECP521PublicKey
+		copy(pk[:], data[:pk.Len()])
+		k = pk
+	}
+	// TODO: rsa/eddsa
+	return
+}