3GPP機密性和完整性算法規範128-EEA3和128-EIA3（一）----密鑰生成原理
3GPP機密性和完整性算法規範128-EEA3和128-EIA3（二）----祖沖之算法的C語言實現
3GPP機密性和完整性算法規範128-EEA3和128-EIA3（三）----機密性算法(EEA3）和完整性算法（EIA3）
3GPP機密性和完整性算法規範128-EEA3和128-EIA3（四）----測試用例
3GPP機密性和完整性算法規範128-EEA3和128-EIA3（五）----文檔代碼資源
英文文檔，特別提示，文中有EEA3和EIA3的代碼
1 OUTLINE OF THE NORMATIVE PART
Section 2 introduces the algorithm and describes the notation used in the subsequent sections.
Section 3 specifies the confidentiality algorithm 128‐EEA3.
Section 4 specifies the integrity algorithm 128‐EIA3.
2
INTRODUCTORY INFORMATION
2.1
Introduction
Within the security architecture of the LTE system there are standardized algorithms for
confidentiality and integrity. Two sets of algorithms 128‐EEA1/128‐EIA1 and 128‐EEA2/128‐EIA2
have already been specified [1‐2]. In this document the third set of these algorithms
(128‐EEA3/128‐EIA3) based on ZUC [3] are proposed.
The confidentiality algorithm 128‐EEA3 is a stream cipher that is used to encrypt/decrypt blocks
of data using a confidentiality key CK. The block of data may be between 1 and 65504 bits long.
The algorithm uses ZUC as a keystream generator.
The integrity algorithm 128‐EIA3 computes a 32‐bit MAC (Message Authentication Code) of a
given input message using an integrity key IK. The core algorithms adopted by the MAC are a
universal hash and ZUC.
2.2
Notations
2.2.1 Radix
In this document, integers are represented as decimal numbers unless specified otherwise. We
use the prefix “0x” to indicate hexadecimal numbers and the subscript “2” to indicate a number
in binary representation.
Example 1.
Integer a can be written in different representations:
a = 1234567890 // decimal representation
= 0x499602D2 // hexadecimal representation
= 10010011001011000000010110100102 //binary representation
2.2.2 Bit/Byte ordering
All data variables in this document are presented with the most significant bit/byte on the left
and the least significant bit/byte on the right. When a variable is broken down into a number of
substrings, the leftmost substring is numbered by 0, the next most significant substring is
numbered by 1 and so on throughout to the least significant substring.
Example 2.
Let a=10010011001011000000010110100102. Then the leftmost bit 1 of integer a
represents its most significant bit, and the rightmost bit 0 represents its least significant bit.
Example 3.
Let a =100100101001011000000010110100102. If a is subdivided into 4 of 8‐bit
substrings a [0], a [1], a [2] and a [3], then we have
a [0] = 100100102, a [1] = 100101102, a [2] = 000000102, a [3] = 110100102.
2.2.3 Operation notations
In this document, operation notations are defined as follows:
a║b Concatenation of substrings a and b
⎡ x ⎤ The smallest integer no less than x
⊕ Exclusive‐OR
a<< t Left shift of integer a by t bits
Example 4.
For two substrings a= 0x1234 and b= 0x5678, then their concatenation will be
c=a║b =0x12345678.
2.2.4 List of Variables
COUNT The 32‐bit counter.
BEARER The 5‐bit bearer identity.
DIRECTION The 1‐bit input indicating the direction of transmission.
CK The 128‐bit confidentiality key.
IK The 128‐bit integrity key.
LENGTH The number of bits to be encrypted/decrypted.
M The input message.
C The output message.
KEY The 128‐bit initial key to ZUC.
IV The 128‐bit initial vector to ZUC.
L The number of key words generated by ZUC.
z[i] The i‐th key bit of keystream generated by ZUC.
3
CONFIDENTIALITY ALGORITHM 128-EEA3
3.1
Introduction
The confidentiality algorithm 128‐EEA3 is a stream cipher that is used to encrypt/decrypt blocks
of data under a confidentiality key. The block of data can be between 1 and 65504 bits in length.
3.2
Inputs and Outputs
The inputs to the algorithm are given in Table 1, the output in Table 2.
Table 1 The inputs to 128‐EEA3
Parameter Size(bits) Remark
COUNT 32 The counter
BEARER 5 The bearer identity
DIRECTION 1 The direction of transmission
CK 128 Confidentiality key
LENGTH 32 The length of the input message
M LENGTH The input bit stream
Table 2 The output of 128‐EEA3
Parameter Size(bits) Remark
C LENGTH The output bit stream
3.3
Initialisation
In this section we define how ZUC’s parameters, the initial key KEY and the initial vector IV, are
initialized with the confidentiality key CK and initialization variables before the generation of
keystream.
Let
CK=CK[0] ║CK[1] ║CK[2] ║…║CK[15]
be the 128‐bit confidentiality key, where CK[i] (0≤i≤15) are bytes. We set the 128‐bit initial key
KEY to ZUC as
KEY = KEY[0] ║KEY[1] ║KEY[2] ║…║KEY[15],
where KEY[i] (0≤i≤15) are bytes. Then
KEY[i]=CK[i], i=0,1,2,…,15.
Let
COUNT=COUNT[0]║COUNT[1]║COUNT[2]║COUNT[3]
be the 32‐bit counter, where COUNT[i] ( 0≤i≤3) are bytes. We set the 128‐bit initial vector to ZUC
as
IV = IV[0]║IV[1] ║IV[2] ║…║IV[15],
where IV[i] ( 0≤i≤15) are bytes. Then
IV[0] = COUNT[0], IV[1] = COUNT[1],
IV[2] = COUNT[2], IV[3] = COUNT[3],
IV[4] = BEARER║DIRECTION║002,
IV[5] = IV[6] = IV[7] = 000000002,
IV[8] = IV[0], IV[9] = IV[1],
IV[10] = IV[2], IV[11] = IV[3],
IV[12] = IV[4], IV[13] = IV[5],
IV[14] = IV[6], IV[15] = IV[7].
3.4
Keystream Generation
Let ZUC generate keystream of L words. When each of the word is expanded into a 32‐bit string,
then we get a binary string z[0], z[1], …, z[32×L‐1], where z[0] is the most significant bit of the
first output word of ZUC and z[31] is the least significant bit. To encrypt a message of LENGTH bits,
it is required that L=⎡LENGTH/32⎤.
3.5
Encryption/Decryption
Encryption/decryption operations are identical operations and are performed by the exclusive‐OR
of the input message M with the generated keystream z.
Let
M = M[0] ║M[1] ║M[2] ║…║M[LENGTH‐1]
be the input bit stream of length LENGTH and
C = C[0] ║C[1] ║C[2] ║…║C[LENGTH‐1]
be the corresponding output bit stream of length LENGTH, where M[i] and C[i] are bits,
i=0,1,2,…,LENGTH‐1. Then
C[i] = M[i]⊕z[i],i=0,1,2,…,LENGTH‐1
4
INTEGRITY ALGORITHM 128-EIA3
4.1
Introduction
The integrity algorithm 128‐EIA3 is a message authentication code (MAC) function that is used to
compute the MAC of an input message using an integrity key IK. The message can be between 1
and 65504 bits in length.
4.2
Inputs and Outputs
The inputs to the algorithm are given in Table 3, and the output is in Table 4.
Table 3 The inputs to 128‐EIA3
Parameter Size (bits) Remark
COUNT 32 The counter
BEARER 5 The bearer identity
DIRECTION 1 The direction of transmission
IK 128 The integrity key
LENGTH 32 The bits of the input message
M LENGTH The input message
Table 4 The output of 128‐EIA3
Parameter Size(bits) Remark
MAC 32 The MAC
4.3
Initialisation
In this section we define how ZUC’s parameters, the initial key KEY and the initial vector IV, are
initialized with the integrity key IK and initialization variables before the generation of keystream.
Let
IK = IK[0] ║IK[1] ║IK[2] ║…║IK[15]
be the 128‐bit integrity key, where IK[i]( 0≤i≤15) are bytes. We set the 128‐bit initial key KEY to
ZUC as
KEY = KEY[0] ║KEY[1] ║KEY[2] ║…║KEY[15]
where KEY[i](0≤i≤15) are bytes. Then
KEY[i] = IK[i], i=0,1,2,…,15.
Let the 32‐bit counter COUNT be
COUNT=COUNT[0] ║COUNT[1] ║COUNT[2] ║COUNT[3]
where COUNT[i] are bytes, i=0,1,2,3. We set the 128‐bit initial vector IV to ZUC as
IV = IV[0] ║IV[1] ║IV[2] ║…║IV[15],
where IV[i]( 0≤i≤15) are bytes. Then
IV[0] = COUNT[0], IV[1] = COUNT[1],
IV[2] = COUNT[2], IV[3] = COUNT[3],
IV[4] = BEARER║0002, IV[5] =000000002,
IV[6] = 000000002, IV[7] = 000000002,
IV[8] = IV[0]⊕ (DIRECTION << 7), IV[9] = IV[1],
IV[10] = IV[2], IV[11] = IV[3],
IV[12] = IV[4], IV[13] = IV[5],
IV[14] = IV[6]⊕(DIRECTION << 7), IV[15] = IV[7].
4.4
Generating the keystream
Let ZUC generate a keystream of L=⎡LENGTH/32⎤+2 words. Denote the generated bit string by z[0],
z[1], …, z[32×L‐1], where z[0] is the most significant bit of the first output word of ZUC and z[31]
is the least significant bit.
For each i=0,1,2,…,32×(L‐1), let
zi = z[i] ║z[i+1] ║…║z[i+31].
Then each zi is a 32‐bit word.
4.5
Compute the MAC
Let T be a 32‐bit word. Set T = 0.
For each i=0,1,2,…,LENGTH‐1, if M[i] = 1, then
T=T zi ⊕ .
Set
T=T ⊕ zLENGTH.
Finally we take T z
⊕
32×(L‐1) as the output MAC, i.e.
MAC= T ⊕ z32×(L‐1)
A C implementation of 128-EEA3
typedef unsigned char u8;
typedef unsigned int u32;
/* The ZUC algorithm, see ref. [3]*/
void ZUC(u8* k, u8* iv, u32* ks, int len)
{
/* The initialization of ZUC, see page 17 of ref. [3]*/
Initialization(k, iv);
/* The procedure of generating keystream of ZUC, see page 18 of ref. [3]*/
GenerateKeystream(ks, len);
}
void EEA3(u8* CK,u32 COUNT,u32 BEARER,u32 DIRECTION,u32 LENGTH,u32* M,u32* C)
{
u32 *z, L, i;
u8 IV[16];
L = (LENGTH+31)/32;
z = (u32 *) malloc(L*sizeof(u32));
IV[0] = (COUNT>>24) & 0xFF;
IV[1] = (COUNT>>16) & 0xFF;
IV[2] = (COUNT>>8) & 0xFF;
IV[3] = COUNT & 0xFF;
IV[4] = ((BEARER << 3) | ((DIRECTION&1)<<2)) & 0xFC;
IV[5] = 0;
IV[6] = 0;
IV[7] = 0;
IV[8] = IV[0];
IV[9] = IV[1];
IV[10] = IV[2];
IV[11] = IV[3];
IV[12] = IV[4];
IV[13] = IV[5];
IV[14] = IV[6];
IV[15] = IV[7];
ZUC(CK,IV,z,L);
for (i=0; i<L; i++)
{
C[i] = M[i] ^ z[i];
}
free(z);
}
ANNEX 2
A C implementation of 128-EIA3
typedef unsigned char u8;
typedef unsigned int u32;
void ZUC(u8* k, u8* iv, u32* keystream, int length); /*see Annex 1*/
u32 GET_WORD(u32 * DATA, u32 i)
{
u32 WORD, ti;
ti = i % 32;
if (ti == 0) {
WORD = DATA[i/32];
}
else {
WORD = (DATA[i/32]<<ti) | (DATA[i/32+1]>>(32-ti));
}
return WORD;
}
u8 GET_BIT(u32 * DATA, u32 i)
{
return (DATA[i/32] & (1<<(31-(i%32)))) ? 1 : 0;
}
void EIA3(u8* IK,u32 COUNT,u32 DIRECTION,u32 BEARER,u32 LENGTH,u32* M,u32* MAC)
{
u32 *z, N, L, T, i;
u8 IV[16];
IV[0] = (COUNT>>24) & 0xFF;
IV[1] = (COUNT>>16) & 0xFF;
IV[2] = (COUNT>>8) & 0xFF;
IV[3] = COUNT & 0xFF;
IV[4] = (BEARER << 3) & 0xF8;
IV[5] = IV[6] = IV[7] = 0;
IV[8] = ((COUNT>>24) & 0xFF) ^ ((DIRECTION&1)<<7);
IV[9] = (COUNT>>16) & 0xFF;
IV[10] = (COUNT>>8) & 0xFF;
IV[11] = COUNT & 0xFF;
IV[12] = IV[4];
IV[13] = IV[5];
IV[14] = IV[6] ^ ((DIRECTION&1)<<7);
IV[15] = IV[7];
N = LENGTH + 64;
L = (N + 31) / 32;
z = (u32 *) malloc(L*sizeof(u32));
ZUC(IK, IV, z, L);
T = 0;
for (i=0; i<LENGTH; i++) {
if (GET_BIT(M,i)) {
T ^= GET_WORD(z,i);
}
}
T ^= GET_WORD(z,LENGTH);
*MAC = T ^ z[L-1];
free(z);
}