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x86 instruction listings |
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Instructions that have been added to the x86 instruction set in order to assist efficient calculation of cryptographic primitives, such as e.g. AES encryption, SHA hash calculation and random number generation.
6 new instructions.
Instruction | Encoding | Description | Added in |
---|---|---|---|
AESENC xmm1,xmm2/m128 | 66 0F 38 DC /r | Perform one round of an AES encryption flow. Performs the SubBytes , ShiftRows , MixColumns and AddRoundKey steps of an AES encryption round, in that order. [a] The first source argument provides a 128-bit data-block to perform an encryption round on, the second source argument provides a round key for the AddRoundKey stage. |
|
AESENCLAST xmm1,xmm2/m128 | 66 0F 38 DD /r | Perform the last round of an AES encryption flow. Performs the SubBytes , ShiftRows and AddRoundKey steps of an AES encryption round, in that order. [a] | |
AESDEC xmm1,xmm2/m128 | 66 0F 38 DE /r | Perform one round of an AES decryption flow. Performs the InvShiftRows , InvSubBytes , InvMixColumns and AddRoundKey steps of an AES decryption round, in that order. [a] [b] | |
AESDECLAST xmm1,xmm2/m128 | 66 0F 38 DF /r | Perform the last round of an AES decryption flow. Performs the InvShiftRows , InvSubBytes and AddRoundKey steps of an AES decryption round, in that order. [a] | |
AESKEYGENASSIST xmm1,xmm2/m128,imm8 | 66 0F 3A DF /r ib | Assist in AES round key generation. The operation performed is: temp[127: 0] := SubBytes( src[127:0] ) // AES SubBytes step dest[ 31: 0] := temp[63:32] dest[ 63:32] := rotate_left( temp[63:32], 8 ) XOR RCON dest[ 95:64] := temp[127:96] dest[127:96] := rotate_left( temp[127:96], 8 ) XOR RCON where RCON is the instruction's imm8 argument zero-extended to 32 bits. | |
AESIMC xmm1,xmm2/m128 | 66 0F 38 DB /r | Perform the InvMixColumns step of an AES decryption round on one 128-bit block.Mainly used to help prepare an AES key for use with the AESDEC instruction. [b] |
SubBytes
and ShiftRows
steps of an AES encryption round may be performed in either order - the result of the instruction is the same either way. [1] (Intel documentation describes the ShiftRows
step as being performed first, while AMD documentation describes SubBytes
as being performed first.) This also applies to the InvShiftRows
/InvSubBytes
steps of an AES decryption round.AESDEC
instructions followed by an AESDECLAST
), the AESDEC
instruction performs the InvMixColumns
and AddRoundKey
steps in the opposite order of what the AES specification (FIPS 197) indicates.AESDEC
cannot just be taken from the Rijndael key schedule directly, but instead has to be postprocessed by performing an InvMixColumn
on the round key after the key schedule and before it's used with AESDEC
[1] (this can be done with the AESIMC
instruction or by doing an AESENCLAST
+AESDEC
sequence with the round key set to 0.)(V)AESDEC
and does not apply to round keys used with the AESENC
, AESENCLAST
or AESDECLAST
instructions.Instruction | Opcode | Description |
---|---|---|
PCLMULQDQ xmm1,xmm2,imm8 | 66 0F 3A 44 /r ib | Perform a carry-less multiplication of two 64-bit polynomials over the finite field GF(2k). |
PCLMULLQLQDQ xmm1,xmm2/m128 | 66 0F 3A 44 /r 00 | Multiply the low halves of the two 128-bit operands. |
PCLMULHQLQDQ xmm1,xmm2/m128 | 66 0F 3A 44 /r 01 | Multiply the high half of the destination register by the low half of the source operand. |
PCLMULLQHQDQ xmm1,xmm2/m128 | 66 0F 3A 44 /r 10 | Multiply the low half of the destination register by the high half of the source operand. |
PCLMULHQHQDQ xmm1,xmm2/m128 | 66 0F 3A 44 /r 11 | Multiply the high halves of the two 128-bit operands. |
Instruction | Encoding | Description | Added in |
---|---|---|---|
RDRAND r16 RDRAND r32 | NFx 0F C7 /6 | Return a random number that has been generated with a CSPRNG (Cryptographically Secure Pseudo-Random Number Generator) compliant with NIST SP 800-90A. [a] | Ivy Bridge, Silvermont, Excavator, Puma, ZhangJiang, Knights Landing, |
RDRAND r64 | NFx REX.W 0F C7 /6 | ||
RDSEED r16 RDSEED r32 | NFx 0F C7 /7 | Return a random number that has been generated with a HRNG/TRNG (Hardware/"True" Random Number Generator) compliant with NIST SP 800-90B and C. [a] | Broadwell, ZhangJiang, Knights Landing, Zen 1, Gracemont |
RDSEED r64 | NFx REX.W 0F C7 /7 |
RDRAND
and RDSEED
instructions may fail to obtain and return a random number if the CPU's random number generators cannot keep up with the issuing of these instructions – if this happens, then software may retry the instructions (although the number of retries should be limited, in order to ensure forward progress [2] ). The instructions set EFLAGS.CF
to 1 if a random number was successfully obtained and 0 otherwise. For RDSEED
, failure to obtain a random number will also set the instruction's destination register to 0.These instructions provide support for cryptographic hash functions such as SHA-1, SHA-256, SHA-512 and SM3. Each of these hash functions works on fixed-size data blocks, where the processing of each data-block mostly consists of two major phases: [3]
For each of the supported hash functions, separate instructions are provided to help compute the message schedule (instructions with "MSG" in their names) and to help perform the compression function rounds (instructions with "RND" in their names).
Hash function extension | Instructions | Encoding [a] | Description | Added in |
---|---|---|---|---|
SHA1RNDS4 xmm1,xmm2/m128,imm8 | NP 0F 3A CC /r ib | Perform Four Rounds of SHA-1 Operation | Goldmont, Zen 1, Cannon Lake, LuJiaZui, Rocket Lake | |
SHA1NEXTE xmm1,xmm2/m128 | NP 0F 38 C8 /r | Calculate SHA-1 State Variable E after Four Rounds | ||
SHA1MSG1 xmm1,xmm2/m128 | NP 0F 38 C9 /r | Perform an Intermediate Calculation for the Next Four SHA-1 Message Dwords | ||
SHA1MSG2 xmm1,xmm2/m128 | NP 0F 38 CA /r | Perform a Final Calculation for the Next Four SHA-1 Message Dwords | ||
SHA256RNDS2 xmm1,xmm2/m128 SHA256RNDS2 xmm1,xmm2/m128,XMM0 [b] | NP 0F 38 CB /r | Perform Two Rounds of SHA256 Operation | ||
SHA256MSG1 xmm1,xmm2/m128 | NP 0F 38 CC /r | Perform an Intermediate Calculation for the Next Four SHA-256 Message Dwords | ||
SHA256MSG2 xmm1,xmm2/m128 | NP 0F 38 CD /r | Perform a Final Calculation for the Next Four SHA-256 Message Dwords | ||
| VSHA512RNDS2 ymm1,ymm2,xmm3 | VEX.256.F2.0F38.W0 CB /r | Perform Two Rounds of SHA-512 operation | Lunar Lake, Arrow Lake |
VSHA512MSG1 ymm1,xmm2 | VEX.256.F2.0F38.W0 CC /r | Perform an Intermediate Calculation for the Next Four SHA-512 Message Qwords | ||
VSHA512MSG2 ymm1,ymm2 | VEX.256.F2.0F38.W0 CD /r | Perform a Final Calculation for the Next Four SHA-512 Message Qwords | ||
| VSM3RNDS2 xmm1,xmm2,xmm3/m128,imm8 | VEX.128.66.0F3A.W0 DE /r ib | Perform Two Rounds of SM3 Operation | Lunar Lake, Arrow Lake |
VSM3MSG1 xmm1,xmm2,xmm3/m128 | VEX.128.NP.0F38.W0 DA /r | Perform Initial Calculation for the Next Four SM3 Message Words | ||
VSM3MSG2 xmm1,xmm2,xmm3/m128 | VEX.128.66.0F38-W0 DA /r | Perform Final Calculation for the Next Four SM3 Message Words |
These instructions, available in Tiger Lake and later Intel processors, are designed to enable encryption/decryption with an AES key without having access to any unencrypted copies of the key during the actual encryption/decryption process.
Key Locker subset | Instruction | Encoding [a] | Description | |
---|---|---|---|---|
| LOADIWKEY xmm1,xmm2 | F3 0F 38 DC /r | Load internal wrapping key ("IWKey") from xmm1, xmm2 and XMM0 . The two explicit operands (which must be register operands) specify a 256-bit encryption key. The implicit operand in
| |
| ENCODEKEY128 r32,r32 | F3 0F 38 FA /r | Wrap a 128-bit AES key from XMM0 into a 384-bit key handle - and output this handle to XMM0-2 . | Source operand specifies handle restrictions to build into the handle. [c] Destination operand is initialized with information about the source and attributes of the key (this matches the value that was provided in EAX for the most recent invocation of These instructions may also modify |
ENCODEKEY256 r32,r32 | F3 0F 3A FB /r | Wrap a 256-bit AES key from XMM1:XMM0 into a 512-bit key handle - and output this handle to XMM0-3 . | ||
AESENC128KL xmm,m384 | F3 0F 38 DC /r | Encrypt xmm using 128-bit AES key indicated by handle at m384 and store result in xmm. [d] | ||
AESDEC128KL xmm,m384 | F3 0F 38 DD /r | Decrypt xmm using 128-bit AES key indicated by handle at m384 and store result in xmm. [d] | ||
AESENC256KL xmm,m512 | F3 0F 38 DE /r | Encrypt xmm using 256-bit AES key indicated by handle at m512 and store result in xmm. [d] | ||
AESDEC256KL xmm,m512 | F3 0F 38 DF /r | Decrypt xmm using 256-bit AES key indicated by handle at m512 and store result in xmm. [d] | ||
| AESENCWIDE128KL m384 | F3 0F 38 D8 /0 | Encrypt XMM0-7 using 128-bit AES key indicated by handle at m384 and store each resultant block back to its corresponding register. [d] | |
AESDECWIDE128KL m384 | F3 0F 38 D8 /1 | Decrypt XMM0-7 using 128-bit AES key indicated by handle at m384 and store each resultant block back to its corresponding register. [d] | ||
AESENCWIDE256KL m512 | F3 0F 38 D8 /2 | Encrypt XMM0-7 using 256-bit AES key indicated by handle at m512 and store each resultant block back to its corresponding register. [d] | ||
AESDECWIDE256KL m512 | F3 0F 38 D8 /3 | Decrypt XMM0-7 using 256-bit AES key indicated by handle at m512 and store each resultant block back to its corresponding register. [d] |
r16-r31
and xmm16-xmm31
registers with these instructions.LOADIWKEY
instruction in the EAX register are: Bits | Flags |
---|---|
0 | 1=Do not permit the wrapping key to be backed up to platform-scoped storage |
4:1 | KeySource field. The following values are supported:
|
31:5 | Reserved, must be set to 0 |
ENCODEKEY128
and ENCODEKEY256
are: Bits | Flags |
---|---|
0 | CPL0-only restriction |
1 | No-encrypt restriction |
2 | No-decrypt restriction |
31:3 | Reserved, must be set to 0 |
The VIA/Zhaoxin PadLock instructions are instructions designed to apply cryptographic primitives in bulk, similar to the 8086 repeated string instructions. As such, unless otherwise specified, they take, as applicable, pointers to source data in ES:rSI and destination data in ES:rDI, and a data-size or count in rCX. Like the old string instructions, they are all designed to be interruptible. [4] [5]
PadLock subset | Instruction mnemonics [a] | Encoding | Description | Added in |
---|---|---|---|---|
| XSTORE ,XSTORE-RNG | NFx 0F A7 C0 | Store random bytes to ES:[rDI], and increment ES:rDI accordingly. XSTORE will store currently-available bytes, which may be from 0 to 8 bytes. REP XSTORE and REP XRNG2 will write the number of random bytes specified by rCX, waiting for the random number generator when needed. [b] EDX specifies a "quality factor". [c] | Nehemiah (stepping 3) |
REP XSTORE ,REP XSTORE-RNG | F3 0F A7 C0 | |||
REP XRNG2 | F3 0F A7 F8 | ZhangJiang [d] | ||
| REP XCRYPT-ECB | F3 0F A7 C8 | Encrypt/Decrypt data, using the AES cipher in various block modes (ECB, CBC, CFB, OFB and CTR, respectively). rCX contains the number of 16-byte blocks to encrypt/decrypt, rBX contains a pointer to an encryption key, ES:rAX a pointer to an initialization vector for block modes that need it, and ES:rDX a pointer to a control word. [e] | Nehemiah (stepping 8) |
REP XCRYPT-CBC | F3 0F A7 D0 | |||
REP XCRYPT-CFB | F3 0F A7 E0 | |||
REP XCRYPT-OFB | F3 0F A7 E8 | |||
| REP XCRYPT-CTR | F3 0F A7 D8 | C7 "Esther" [9] | |
| REP XSHA1 | F3 0F A6 C8 | Compute a cryptographic hash (using the SHA-1 and SHA-256 functions, respectively). ES:rSI points to data to compute a hash for, ES:rDI points to a message digest and rCX specifies the number of bytes. rAX should be set to 0 at the start of a calculation. [g] | Esther |
REP XSHA256 | F3 0F A6 D0 | |||
REP XSHA384 | F3 0F A6 D8 | Perform computation of a SHA-384/SHA-512 cryptographic hash. ES:rSI points to a series of 128-byte data chunks to perform hash computation for, ES:rDI points to a 64-byte digest to update, and ECX specifies the number of chunks to process. [h] | ZhangJiang [d] | |
REP XSHA512 | F3 0F A6 E0 | |||
| REP MONTMUL | F3 0F A6 C0 [i] | Perform Montgomery Multiplication. Takes an operand width in ECX (given as a number of bits – must be in range 256..32768 and divisible by 128) and pointer to a data structure in ES:ESI. [j] When starting a new Montgomery Multiplication, EAX and the result buffer in memory must be filled with all-0s before executing the | Esther |
REP MONTMUL2 | F3 0F A6 F0 | Perform modular multiplication/exponentiation. Takes pointers (all using the ES: segment) to bignum integers in registers rAX, rBX, rDX, rDI, respectively, where and are input numbers, is a modulus, [k] and will be overwritten with the result. The operation performed is:
ECX provides the size of the bignums, in number of bits (256..32768, must be divisble by 128), and ES:rSI provides a pointer to a scratchpad area to use during the calculation. [l] | ZhangJiang [d] | |
REP XMODEXP | F3 0F A6 F8 | |||
CCS_HASH ,CCS_SM3 [m] | F3 0F A6 E8 | Compute SM3 hash, similar to the REP XSHA* instructions. The rBX register is used to specify hash function (20h for SM3 being the only documented value). | ZhangJiang | |
CCS_ENCRYPT ,CCS_SM4 [m] | F3 0F A7 F0 | Encrypt/Decrypt data, using the SM4 cipher in various block modes. rCX contains the number of 16-byte blocks to encrypt/decrypt, rBX contains a pointer to an encryption key, rDX a pointer to an initialization vector for block modes that need it, and rAX contains a control word. [n] | ||
SM2 [14] | F2 0F A6 C0 | Perform SM2 (public key cryptographic algorithm) function. The function to perform is specified in bits 5:0 of EDX [o] - depending on function, rAX/rBX/rCX/rSI/rDI may provide additional input arguments. The instruction returns a status bit in EDX bit 6 (0=success, 1=failure) - depending on function, rAX, rCX and rDI may be modified as well. | KX-6000G |
REP
prefix optional for instructions other than XSTORE
- with such assemblers, the PadLock instructions will be assembled with one F3
(REP
) prefix byte regardless of whether the assembly instruction is written with REP
or not. (The F3
prefix is mandatory for all PadLock instructions except XSTORE
.)REP XSTORE
instruction (but not REP XRNG2
) may write not just the number of bytes specified in ECX, but up to 7 additional bytes as well. [7] REP XRNG2
instruction, bits 1:0 of EDX are used to indicate whether the instruction should return hardware random numbers directly (EDX[1:0]==0) or return postprocessed numbers (EDX[1:0] ≠ 0).REP XRNG2
, REP XSHA384
, REP XSHA512
, REP MONTMUL2
and REP XMODEXP
instructions exist as documented instructions only on Zhaoxin processors. [5] REP XCRYPT*
is a 16-byte (128-bit) data structure with the following layout: Bits | Usage |
---|---|
3:0 | AES round count |
4 | Digest mode enable (ACE2 only) |
5 | 1=allow data that are not 16-byte aligned (ACE2 only) |
6 | Cipher: 0=AES, 1=undefined |
7 | Key schedule: 0=compute (128-bit key only), 1=load from memory |
8 | 0=normal, 1=intermediate-result |
9 | 0=encrypt, 1=decrypt |
11:10 | Key size: 00=128-bit,01=192-bit,10=256-bit, 11=reserved |
127:12 | Reserved, must be set to 0 |
REP XCRYPT*
instructions will use the 112 bytes directly after the control word as a scratchpad memory area for data realignment.REP XCRYPT-CTR
instruction, ACE2 also adds extra features to the other REP XCRYPT
instructions: a digest mode for the CBC and CFB instructions, and the ability to use input/output data that are not 16-byte aligned for the non-ECB instructions.REP XSHA*
instructions will enable an alternate operation mode, where rCX specifies the number of 64-byte blocks, and where the standard FIPS-180-2 length extension procedure at the end of the hash calculation is omitted. This makes for a variant more suitable for data streaming than the original EAX=0 variant. [10] This functionality also exists for CCS_HASH
.REP XSHA384
and REP XSHA512
instructions perform identical operations.REP MONTMUL
instruction is only supported with an AddressSize of 32 bits - for this reason, the address-size override prefix (67h
) is required in 16-bit and 64-bit modes, but disallowed in 32-bit mode.REP MONTMUL
contains six 32-bit elements, where the first one is a negated modular inverse of the bottom 32 bits of the modulus and the remaining 5 are pointers to various memory buffers (each of which uses the ES segment and must be 16-byte aligned): Offset | Data item |
---|---|
0 | Negated modular inverse |
4 | Pointer to first multiplicand |
8 | Pointer to second multiplicand |
12 | Pointer to result buffer |
16 | Pointer to modulus |
20 | Pointer to 32-byte scratchpad |
REP MONTMUL2
and REP XMODEXP
, the modulus is required to be greater than both and , and is also required to be odd. The instructions will produce a #GP exception if this is not the case.REP MONTMUL2
and REP XMODEXP
must have a size of at least bytes (e.g. for a 2048-bit bignum size, the scratchpad must be at least 808 bytes). Also, before starting either of these instructions, the 8 first bytes of this scratchpad must be zeroed out and the bignum size given in ECX must also be written as a 64-bit integer to the next 8 bytes.CCS_SM3
/CCS_SM4
mnemomics are used in a 2019 article, [13] while CCS_HASH
/CCS_ENCRYPT
are used in a 2020 article. [11] CCS_ENCRYPT
control word in rAX has the following format: Bits | Usage |
---|---|
0 | 0=Encrypt, 1=Decrypt |
5:1 | Must be 10000b for SM4. |
6 | ECB block mode |
7 | CBC block mode |
8 | CFB block mode |
9 | OFB block mode |
10 | CTR block mode |
11 | Digest enable |
SM2
instruction are: Value | Meaning |
---|---|
0x01 | Encryption |
0x02 | Decryption |
0x04 | Signature |
0x08 | Verify signature |
0x10 | Key exchange 1 |
0x11 | Key exchange 2 without hash |
0x12 | Key exchange 3 without hash |
0x15 | Key exchange 2 with hash |
0x16 | Key exchange 3 with hash |
0x20 | Preprocess1 to calculate hash value Z of user’s identification |
0x21 | Preprocess2 to calculate hash value e of hash value Z and message M |
SM2
instruction. Archived on 9 Nov 2024; attachment archived on 9 Nov 2024.