< draft-songlee-aes-cmac-00.txt		draft-songlee-aes-cmac-01.txt >
	JunHyuk Song		JunHyuk Song
	Jicheol Lee		Jicheol Lee
	INTERNET DRAFT Samsung Electronics		INTERNET DRAFT Samsung Electronics
	Expires: November 24, 2005 May 25 2005		Expires: November 30, 2005 May 31 2005
	The AES-CMAC Algorithm		The AES-CMAC Algorithm
	draft-songlee-aes-cmac-00.txt		draft-songlee-aes-cmac-01.txt
	Status of This Memo		Status of This Memo
	By submitting this Internet-Draft, each author represents that any		By submitting this Internet-Draft, each author represents that any
	applicable patent or other IPR claims of which he or she is aware		applicable patent or other IPR claims of which he or she is aware
	have been or will be disclosed, and any of which he or she becomes		have been or will be disclosed, and any of which he or she becomes
	aware will be disclosed, in accordance with Section 6 of BCP 79.		aware will be disclosed, in accordance with Section 6 of BCP 79.
	Internet-Drafts are working documents of the Internet Engineering		Internet-Drafts are working documents of the Internet Engineering
	Task Force (IETF), its areas, and its working groups. Note that		Task Force (IETF), its areas, and its working groups. Note that
	skipping to change at page 2, line 34 ¶		skipping to change at page 2, line 34 ¶
	1. Introduction		1. Introduction
	National Institute of Standards and Technology (NIST) has newly		National Institute of Standards and Technology (NIST) has newly
	specified the Cipher based MAC (CMAC). CMAC [NIST-CMAC] is a keyed		specified the Cipher based MAC (CMAC). CMAC [NIST-CMAC] is a keyed
	hashed function that is based on a symmetric key block cipher such		hashed function that is based on a symmetric key block cipher such
	as Advanced Encryption Standard [AES]. CMAC is equivalent to the		as Advanced Encryption Standard [AES]. CMAC is equivalent to the
	One-Key CBC-MAC1 (OMAC1) algorithm submitted by Iwata and Kurosawa		One-Key CBC-MAC1 (OMAC1) algorithm submitted by Iwata and Kurosawa
	[OMAC1]. Although the OMAC1 algorithm is based on the eXtended Cipher		[OMAC1]. Although the OMAC1 algorithm is based on the eXtended Cipher
	Block Chaining mode (XCBC) algorithm submitted by Rogaway and Black		Block Chaining mode (XCBC) algorithm submitted by Rogaway and Black
	[XCBC], OMAC1 efficiently reduces the key size of XCBC.		[XCBC], OMAC1 efficiently reduces the key size of XCBC. This memo
	This memo specifies the authentication mechanism based on		specifies the authentication mechanism based on CMAC mode of
	CMAC mode of operation with 128-bit Advanced Encryption Standard		operation with 128-bit Advanced Encryption Standard(AES) cipher
	(AES) cipher block. This new authentication algorithm is named		block. This new authentication algorithm is named AES-CMAC
	AES-CMAC
	2. Specification of Language		2. Specification of Language
	The keywords "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",		The keywords "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
	"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this		"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
	document are to be interpreted as described in RFC 2119 [3].		document are to be interpreted as described in RFC 2119 [3].
	In addition, the following words are used to signify the requirements		In addition, the following words are used to signify the requirements
	of the specification.		of the specification.
	skipping to change at page 7, line 5 ¶		skipping to change at page 7, line 5 ¶
	+ else K1 := (L << 1) XOR const_Rb; +		+ else K1 := (L << 1) XOR const_Rb; +
	+ Step 3. if MSB(K1) is equal to 0 +		+ Step 3. if MSB(K1) is equal to 0 +
	+ then K2 := K1 << 1; +		+ then K2 := K1 << 1; +
	+ else K2 := (K1 << 1) XOR const_Rb; +		+ else K2 := (K1 << 1) XOR const_Rb; +
	+ Step 4. return K1, K2; +		+ Step 4. return K1, K2; +
	+ +		+ +
	+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++		+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
	Figure 3.2 Generate_Subkey Algorithm		Figure 3.2 Generate_Subkey Algorithm
	Figure 3.2 describes the algorithm generating subkeys.		Figure 3.2 describes the algorithm generating subkeys.
	In step 1. AES-128 is applied to all zero bits with key k		In step 1. AES-128 is applied to all zero bits with key K.
	In step 2 K1 is derive through following operation:		In step 2 K1 is derive through following operation:
	If the most significant bit of L is equal to 0, left-shift L by 1		If the most significant bit of L is equal to 0, left-shift L by 1
	bit. Otherwise, exclusive-OR const_Rb with the result of 1-bit		bit. Otherwise, exclusive-OR const_Rb with the result of 1-bit
	left-shift of L.		left-shift of L.
	In step 3. K2 is derived through following operation:		In step 3. K2 is derived through following operation:
	If the most significant bit of K1 is equal to 0, left-shift		If the most significant bit of K1 is equal to 0, left-shift
	K1 by 1 bit. Otherwise, exclusive-OR const_Rb with the result		K1 by 1 bit. Otherwise, exclusive-OR const_Rb with the result
	of 1-bit left-shift of K1.		of 1-bit left-shift of K1.
	skipping to change at page 9, line 40 ¶		skipping to change at page 9, line 40 ¶
	As is true with any cryptographic algorithm, part of its strength		As is true with any cryptographic algorithm, part of its strength
	lies in the correctness of the algorithm implementation, the security		lies in the correctness of the algorithm implementation, the security
	of the key management mechanism and its implementation, the strength		of the key management mechanism and its implementation, the strength
	of the associated secret key, and upon the correctness of the		of the associated secret key, and upon the correctness of the
	implementation in all of the participating systems. This document		implementation in all of the participating systems. This document
	contains test vectors to assist in verifying the correctness of		contains test vectors to assist in verifying the correctness of
	AES-CMAC code.		AES-CMAC code.
	5. Test Vectors		5. Test Vectors
	Following test vectors are same as that of [NIST-CMAC].		Following test vectors are same as those of [NIST-CMAC].
	The following vectors are also output of the test program in		The following vectors are also output of the test program in
	appendix A.		appendix A.
	--------------------------------------------------		--------------------------------------------------
	Subkey Generation		Subkey Generation
	K 2b7e1516 28aed2a6 abf71588 09cf4f3c		K 2b7e1516 28aed2a6 abf71588 09cf4f3c
	AES_128(key,0) 7df76b0c 1ab899b3 3e42f047 b91b546f		AES_128(key,0) 7df76b0c 1ab899b3 3e42f047 b91b546f
	K1 fbeed618 35713366 7c85e08f 7236a8de		K1 fbeed618 35713366 7c85e08f 7236a8de
	K2 f7ddac30 6ae266cc f90bc11e e46d513b		K2 f7ddac30 6ae266cc f90bc11e e46d513b
	--------------------------------------------------		--------------------------------------------------
	skipping to change at page 13, line 42 ¶		skipping to change at page 13, line 42 ¶
	unsigned char sbox(unsigned char a)		unsigned char sbox(unsigned char a)
	{		{
	return sbox_table[(int)a];		return sbox_table[(int)a];
	}		}
	void next_key(unsigned char *key, int round)		void next_key(unsigned char *key, int round)
	{		{
	unsigned char rcon;		unsigned char rcon;
	unsigned char sbox_key[4];		unsigned char sbox_key[4];
	unsigned char rcon_table[12] {		unsigned char rcon_table[12] = {
	0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80,		0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80,
	0x1b, 0x36, 0x36, 0x36		0x1b, 0x36, 0x36, 0x36
	};		};
	sbox_key[0] = sbox(key[13]);		sbox_key[0] = sbox(key[13]);
	sbox_key[1] = sbox(key[14]);		sbox_key[1] = sbox(key[14]);
	sbox_key[2] = sbox(key[15]);		sbox_key[2] = sbox(key[15]);
	sbox_key[3] = sbox(key[12]);		sbox_key[3] = sbox(key[12]);
	rcon = rcon_table[round];		rcon = rcon_table[round];
End of changes. 7 change blocks.
	11 lines changed or deleted		10 lines changed or added
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