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Further reduce mentions of "TR-31". The TR-31 specification is
deprecated and therefore the name "TR-31" should only refer to the
library itself or to types provided by the library. The actual key block
concepts and functionality now involve multiple other specifications
while only the library itself is still called "TR-31".

src/tr31.c

@@ -41,7 +41,7 @@
 
 #define sizeof_field(TYPE, FIELD) sizeof(((TYPE*)0)->FIELD)
 
-// TR-31 header
+// key block header
 // see ANSI X9.143:2021, 6.2, table 1
 struct tr31_header_t {
 	uint8_t version_id;
@@ -56,14 +56,14 @@ struct tr31_header_t {
 	char reserved;
 } __attribute__((packed));
 
-// TR-31 optional block header with short length
+// optional block header with short length
 // see ANSI X9.143:2021, 6.2, table 1
 struct tr31_opt_blk_hdr_t {
 	uint16_t id;
 	char length[2] NONSTRING;
 } __attribute__((packed));
 
-// TR-31 optional block header with extended length
+// optional block header with extended length
 // see ANSI X9.143:2021, 6.2, table 1
 struct tr31_opt_blk_hdr_ext_t {
 	uint16_t id;
@@ -72,15 +72,15 @@ struct tr31_opt_blk_hdr_ext_t {
 	char ext_length[] NONSTRING;
 } __attribute__((packed));
 
-// TR-31 optional block with short length
+// optional block with short length
 // see ANSI X9.143:2021, 6.2, table 1
 struct tr31_opt_blk_t {
 	uint16_t id;
 	char length[2] NONSTRING;
 	char data[];
 } __attribute__((packed));
 
-// TR-31 payload
+// key block payload
 // see ANSI X9.143:2021, 6.1, figure 2
 // see ANSI X9.143:2021, 7.3.1, figure 11 and table 26
 struct tr31_payload_t {
@@ -89,7 +89,7 @@ struct tr31_payload_t {
 } __attribute__((packed));
 
 #define TR31_MIN_PAYLOAD_LENGTH (DES_BLOCK_SIZE)
-#define TR31_MIN_KEY_BLOCK_LENGTH (sizeof(struct tr31_header_t) + TR31_MIN_PAYLOAD_LENGTH + 8) // Minimum TR-31 key block length: header + minimum payload + authenticator
+#define TR31_MIN_KEY_BLOCK_LENGTH (sizeof(struct tr31_header_t) + TR31_MIN_PAYLOAD_LENGTH + 8) // Minimum key block length: header + minimum payload + authenticator
 
 // Internal processing state
 struct tr31_state_t {
@@ -768,7 +768,7 @@ int tr31_init_from_header(
 		return r;
 	}
 
-	// initialise TR-31 context object
+	// initialise key block context object
 	r = tr31_init(header->version_id, NULL, ctx);
 	if (r) {
 		// return error value as-is
@@ -2023,7 +2023,7 @@ int tr31_import(
 		return r;
 	}
 
-	// initialise TR-31 context object
+	// initialise key block context object
 	r = tr31_init(header->version_id, NULL, ctx);
 	if (r) {
 		// return error value as-is
@@ -2461,8 +2461,8 @@ int tr31_export(
 	// ISO 20038:2017, A.2.1 (page 10) indicates that the total length of all
 	// optional blocks must be a multiple of the encryption block size and
 	// does not make an exception for format version E.
-	// So we'll use the encryption block size which is determined by the TR-31
-	// format version.
+	// So we'll use the encryption block size which is determined by the key
+	// block format version.
 	if (opt_blk_len_total & (state.enc_block_size-1)) {
 		unsigned int pb_len = 4; // Minimum length of optional block PB
 
@@ -3175,7 +3175,7 @@ static int tr31_tdes_decrypt_verify_variant_binding(const struct tr31_state_t* s
 		goto error;
 	}
 
-	// decrypt key payload; note that the TR-31 header is used as the IV
+	// decrypt key payload; note that the key block header is used as the IV
 	decrypted_payload = malloc(state->payload_length);
 	r = crypto_tdes_decrypt(
 		kbek,
@@ -3243,7 +3243,7 @@ static int tr31_tdes_encrypt_sign_variant_binding(struct tr31_state_t* state, co
 		goto error;
 	}
 
-	// encrypt key payload; note that the TR-31 header is used as the IV
+	// encrypt key payload; note that the key block header is used as the IV
 	encrypted_payload = malloc(state->payload_length);
 	r = crypto_tdes_encrypt(
 		kbek,