diff --git a/inc/edhoc/plaintext.h b/inc/edhoc/plaintext.h
index 3ee3b8e2..d79e69c3 100644
--- a/inc/edhoc/plaintext.h
+++ b/inc/edhoc/plaintext.h
@@ -15,6 +15,10 @@
 
 #include "common/oscore_edhoc_error.h"
 
+/* draft-ietf-lake-edhoc-22: 3.3.2. Representation of Byte String Identifiers */
+#define ONE_BYTE_CBOR_ENCODED_INT_MIN_VAL ( -24 )
+#define ONE_BYTE_CBOR_ENCODED_INT_MAX_VAL (  23 )
+
 /**
  * @brief                       Decodes id_cred to kid.
  * 
diff --git a/src/edhoc/plaintext_decode.c b/src/edhoc/plaintext_decode.c
index 34f50a18..58a2a47f 100644
--- a/src/edhoc/plaintext_decode.c
+++ b/src/edhoc/plaintext_decode.c
@@ -11,6 +11,7 @@
 
 #include <stdint.h>
 #include <stdbool.h>
+#include <stddef.h>
 
 #include "edhoc/retrieve_cred.h"
 #include "edhoc/plaintext.h"
@@ -43,13 +44,33 @@ static enum err id_cred_x_encode(enum id_cred_x_label label, int algo,
 
 	switch (label) {
 	case kid:
+	{
 		//todo update that to v15
 		map._id_cred_x_map_kid_present = true;
-		map._id_cred_x_map_kid._id_cred_x_map_kid_choice =
-			_id_cred_x_map_kid_int;
-		map._id_cred_x_map_kid._id_cred_x_map_kid_int =
-			*((const int32_t *)id);
+
+		int32_t kid_as_int = 0;
+		const size_t kid_as_int_len = 
+			(id_len < sizeof(kid_as_int)) ?
+			id_len : sizeof(kid_as_int);
+		memcpy(&kid_as_int, id, kid_as_int_len);
+
+		if (kid_as_int >= ONE_BYTE_CBOR_ENCODED_INT_MIN_VAL &&
+		    kid_as_int <= ONE_BYTE_CBOR_ENCODED_INT_MIN_VAL) {
+			map._id_cred_x_map_kid._id_cred_x_map_kid_choice =
+				_id_cred_x_map_kid_int;
+			map._id_cred_x_map_kid._id_cred_x_map_kid_int =
+				*((const int32_t *)id);
+		} else {
+			map._id_cred_x_map_kid._id_cred_x_map_kid_choice =
+				_id_cred_x_map_kid_bstr;
+			map._id_cred_x_map_kid._id_cred_x_map_kid_bstr.value =
+				(const uint8_t *)id;
+			map._id_cred_x_map_kid._id_cred_x_map_kid_bstr.len =
+				id_len;
+		}
+
 		break;
+	}
 	case x5chain:
 		map._id_cred_x_map_x5chain_present = true;
 		map._id_cred_x_map_x5chain._id_cred_x_map_x5chain.value = id;
@@ -120,7 +141,12 @@ enum err plaintext_split(struct byte_array *ptxt, struct byte_array *id_cred_x,
 				kid, 0, p._plaintext_ID_CRED_x_bstr.value,
 				(uint32_t)p._plaintext_ID_CRED_x_bstr.len,
 				id_cred_x));
-
+		} else if (_plaintext_ID_CRED_x_bstr ==
+				   p._plaintext_ID_CRED_x_choice) {
+			TRY(id_cred_x_encode(
+				kid, 0, p._plaintext_ID_CRED_x_bstr.value,
+              			(uint32_t)p._plaintext_ID_CRED_x_bstr.len,
+               			id_cred_x));
 		} else {
 			int _kid = p._plaintext_ID_CRED_x_int;
 			TRY(id_cred_x_encode(kid, 0, &_kid, 1, id_cred_x));
diff --git a/src/edhoc/plaintext_encode.c b/src/edhoc/plaintext_encode.c
index 8993210f..2ad01fe7 100644
--- a/src/edhoc/plaintext_encode.c
+++ b/src/edhoc/plaintext_encode.c
@@ -10,6 +10,7 @@
 */
 
 #include <stdint.h>
+#include <stddef.h>
 
 #include "edhoc/retrieve_cred.h"
 #include "edhoc/signature_or_mac_msg.h"
@@ -22,6 +23,7 @@
 
 #include "cbor/edhoc_decode_id_cred_x.h"
 #include "cbor/edhoc_encode_int_type.h"
+#include "cbor/edhoc_encode_bstr_type.h"
 
 enum err id_cred2kid(const struct byte_array *id_cred, struct byte_array *kid)
 {
@@ -33,12 +35,30 @@ enum err id_cred2kid(const struct byte_array *id_cred, struct byte_array *kid)
 		   0);
 
 	if (map._id_cred_x_map_kid_present) {
-		TRY_EXPECT(
-			cbor_encode_int_type_i(
-				kid->ptr, kid->len,
-				&map._id_cred_x_map_kid._id_cred_x_map_kid_int,
-				&payload_len_out),
-			ZCBOR_SUCCESS);
+		int32_t kid_as_int = 0;
+		const size_t kid_as_int_len = 
+			(id_cred->len < sizeof(kid_as_int)) ? 
+			id_cred->len : sizeof(kid_as_int);
+		memcpy(&kid_as_int, id_cred->ptr, kid_as_int_len);
+
+		if (_id_cred_x_map_kid_int == map._id_cred_x_map_kid._id_cred_x_map_kid_choice &&
+			kid_as_int >= ONE_BYTE_CBOR_ENCODED_INT_MIN_VAL &&
+			kid_as_int <= ONE_BYTE_CBOR_ENCODED_INT_MIN_VAL) {
+				TRY_EXPECT(
+					cbor_encode_int_type_i(
+						kid->ptr, kid->len,
+						&map._id_cred_x_map_kid._id_cred_x_map_kid_int,
+						&payload_len_out),
+					ZCBOR_SUCCESS);
+		} else {
+			TRY_EXPECT(
+				cbor_encode_bstr_type_b_str(
+					kid->ptr, kid->len,
+                   			&map._id_cred_x_map_kid._id_cred_x_map_kid_bstr,
+                   			&payload_len_out),
+               		ZCBOR_SUCCESS);
+		}
+
 		kid->len = (uint32_t)payload_len_out;
 	} else {
 		kid->len = 0;