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284 lines
6.2 KiB
284 lines
6.2 KiB
10 years ago
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/*
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* Key handling functions for PPC AES implementation
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*
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* Copyright (c) 2015 Markus Stockhausen <stockhausen@collogia.de>
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License as published by the Free
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* Software Foundation; either version 2 of the License, or (at your option)
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* any later version.
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*
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*/
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#include <asm/ppc_asm.h>
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#ifdef __BIG_ENDIAN__
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#define LOAD_KEY(d, s, off) \
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lwz d,off(s);
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#else
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#define LOAD_KEY(d, s, off) \
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li r0,off; \
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lwbrx d,s,r0;
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#endif
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#define INITIALIZE_KEY \
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stwu r1,-32(r1); /* create stack frame */ \
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stw r14,8(r1); /* save registers */ \
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stw r15,12(r1); \
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stw r16,16(r1);
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#define FINALIZE_KEY \
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lwz r14,8(r1); /* restore registers */ \
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lwz r15,12(r1); \
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lwz r16,16(r1); \
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xor r5,r5,r5; /* clear sensitive data */ \
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xor r6,r6,r6; \
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xor r7,r7,r7; \
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xor r8,r8,r8; \
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xor r9,r9,r9; \
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xor r10,r10,r10; \
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xor r11,r11,r11; \
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xor r12,r12,r12; \
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addi r1,r1,32; /* cleanup stack */
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#define LS_BOX(r, t1, t2) \
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lis t2,PPC_AES_4K_ENCTAB@h; \
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ori t2,t2,PPC_AES_4K_ENCTAB@l; \
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rlwimi t2,r,4,20,27; \
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lbz t1,8(t2); \
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rlwimi r,t1,0,24,31; \
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rlwimi t2,r,28,20,27; \
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lbz t1,8(t2); \
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rlwimi r,t1,8,16,23; \
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rlwimi t2,r,20,20,27; \
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lbz t1,8(t2); \
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rlwimi r,t1,16,8,15; \
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rlwimi t2,r,12,20,27; \
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lbz t1,8(t2); \
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rlwimi r,t1,24,0,7;
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#define GF8_MUL(out, in, t1, t2) \
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lis t1,0x8080; /* multiplication in GF8 */ \
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ori t1,t1,0x8080; \
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and t1,t1,in; \
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srwi t1,t1,7; \
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mulli t1,t1,0x1b; \
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lis t2,0x7f7f; \
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ori t2,t2,0x7f7f; \
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and t2,t2,in; \
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slwi t2,t2,1; \
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xor out,t1,t2;
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/*
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* ppc_expand_key_128(u32 *key_enc, const u8 *key)
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*
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* Expand 128 bit key into 176 bytes encryption key. It consists of
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* key itself plus 10 rounds with 16 bytes each
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*
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*/
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_GLOBAL(ppc_expand_key_128)
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INITIALIZE_KEY
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LOAD_KEY(r5,r4,0)
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LOAD_KEY(r6,r4,4)
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LOAD_KEY(r7,r4,8)
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LOAD_KEY(r8,r4,12)
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stw r5,0(r3) /* key[0..3] = input data */
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stw r6,4(r3)
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stw r7,8(r3)
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stw r8,12(r3)
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li r16,10 /* 10 expansion rounds */
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lis r0,0x0100 /* RCO(1) */
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ppc_expand_128_loop:
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addi r3,r3,16
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mr r14,r8 /* apply LS_BOX to 4th temp */
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rotlwi r14,r14,8
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LS_BOX(r14, r15, r4)
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xor r14,r14,r0
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xor r5,r5,r14 /* xor next 4 keys */
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xor r6,r6,r5
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xor r7,r7,r6
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xor r8,r8,r7
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stw r5,0(r3) /* store next 4 keys */
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stw r6,4(r3)
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stw r7,8(r3)
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stw r8,12(r3)
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GF8_MUL(r0, r0, r4, r14) /* multiply RCO by 2 in GF */
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subi r16,r16,1
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cmpwi r16,0
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bt eq,ppc_expand_128_end
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b ppc_expand_128_loop
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ppc_expand_128_end:
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FINALIZE_KEY
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blr
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/*
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* ppc_expand_key_192(u32 *key_enc, const u8 *key)
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*
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* Expand 192 bit key into 208 bytes encryption key. It consists of key
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* itself plus 12 rounds with 16 bytes each
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*
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*/
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_GLOBAL(ppc_expand_key_192)
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INITIALIZE_KEY
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LOAD_KEY(r5,r4,0)
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LOAD_KEY(r6,r4,4)
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LOAD_KEY(r7,r4,8)
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LOAD_KEY(r8,r4,12)
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LOAD_KEY(r9,r4,16)
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LOAD_KEY(r10,r4,20)
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stw r5,0(r3)
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stw r6,4(r3)
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stw r7,8(r3)
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stw r8,12(r3)
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stw r9,16(r3)
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stw r10,20(r3)
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li r16,8 /* 8 expansion rounds */
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lis r0,0x0100 /* RCO(1) */
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ppc_expand_192_loop:
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addi r3,r3,24
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mr r14,r10 /* apply LS_BOX to 6th temp */
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rotlwi r14,r14,8
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LS_BOX(r14, r15, r4)
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xor r14,r14,r0
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xor r5,r5,r14 /* xor next 6 keys */
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xor r6,r6,r5
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xor r7,r7,r6
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xor r8,r8,r7
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xor r9,r9,r8
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xor r10,r10,r9
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stw r5,0(r3)
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stw r6,4(r3)
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stw r7,8(r3)
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stw r8,12(r3)
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subi r16,r16,1
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cmpwi r16,0 /* last round early kick out */
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bt eq,ppc_expand_192_end
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stw r9,16(r3)
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stw r10,20(r3)
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GF8_MUL(r0, r0, r4, r14) /* multiply RCO GF8 */
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b ppc_expand_192_loop
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ppc_expand_192_end:
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FINALIZE_KEY
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blr
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/*
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* ppc_expand_key_256(u32 *key_enc, const u8 *key)
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*
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* Expand 256 bit key into 240 bytes encryption key. It consists of key
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* itself plus 14 rounds with 16 bytes each
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*
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*/
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_GLOBAL(ppc_expand_key_256)
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INITIALIZE_KEY
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LOAD_KEY(r5,r4,0)
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LOAD_KEY(r6,r4,4)
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LOAD_KEY(r7,r4,8)
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LOAD_KEY(r8,r4,12)
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LOAD_KEY(r9,r4,16)
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LOAD_KEY(r10,r4,20)
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LOAD_KEY(r11,r4,24)
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LOAD_KEY(r12,r4,28)
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stw r5,0(r3)
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stw r6,4(r3)
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stw r7,8(r3)
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stw r8,12(r3)
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stw r9,16(r3)
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stw r10,20(r3)
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stw r11,24(r3)
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stw r12,28(r3)
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li r16,7 /* 7 expansion rounds */
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lis r0,0x0100 /* RCO(1) */
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ppc_expand_256_loop:
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addi r3,r3,32
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mr r14,r12 /* apply LS_BOX to 8th temp */
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rotlwi r14,r14,8
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LS_BOX(r14, r15, r4)
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xor r14,r14,r0
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xor r5,r5,r14 /* xor 4 keys */
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xor r6,r6,r5
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xor r7,r7,r6
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xor r8,r8,r7
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mr r14,r8
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LS_BOX(r14, r15, r4) /* apply LS_BOX to 4th temp */
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xor r9,r9,r14 /* xor 4 keys */
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xor r10,r10,r9
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xor r11,r11,r10
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xor r12,r12,r11
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stw r5,0(r3)
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stw r6,4(r3)
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stw r7,8(r3)
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stw r8,12(r3)
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subi r16,r16,1
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cmpwi r16,0 /* last round early kick out */
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bt eq,ppc_expand_256_end
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stw r9,16(r3)
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stw r10,20(r3)
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stw r11,24(r3)
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stw r12,28(r3)
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GF8_MUL(r0, r0, r4, r14)
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b ppc_expand_256_loop
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ppc_expand_256_end:
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FINALIZE_KEY
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blr
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/*
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* ppc_generate_decrypt_key: derive decryption key from encryption key
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* number of bytes to handle are calculated from length of key (16/24/32)
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*
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*/
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_GLOBAL(ppc_generate_decrypt_key)
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addi r6,r5,24
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slwi r6,r6,2
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lwzx r7,r4,r6 /* first/last 4 words are same */
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stw r7,0(r3)
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lwz r7,0(r4)
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stwx r7,r3,r6
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addi r6,r6,4
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lwzx r7,r4,r6
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stw r7,4(r3)
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lwz r7,4(r4)
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stwx r7,r3,r6
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addi r6,r6,4
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lwzx r7,r4,r6
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stw r7,8(r3)
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lwz r7,8(r4)
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stwx r7,r3,r6
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addi r6,r6,4
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lwzx r7,r4,r6
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stw r7,12(r3)
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lwz r7,12(r4)
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stwx r7,r3,r6
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addi r3,r3,16
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add r4,r4,r6
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subi r4,r4,28
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addi r5,r5,20
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srwi r5,r5,2
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ppc_generate_decrypt_block:
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li r6,4
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mtctr r6
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ppc_generate_decrypt_word:
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lwz r6,0(r4)
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GF8_MUL(r7, r6, r0, r7)
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GF8_MUL(r8, r7, r0, r8)
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GF8_MUL(r9, r8, r0, r9)
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xor r10,r9,r6
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xor r11,r7,r8
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xor r11,r11,r9
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xor r12,r7,r10
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rotrwi r12,r12,24
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xor r11,r11,r12
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xor r12,r8,r10
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rotrwi r12,r12,16
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xor r11,r11,r12
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rotrwi r12,r10,8
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xor r11,r11,r12
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stw r11,0(r3)
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addi r3,r3,4
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addi r4,r4,4
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bdnz ppc_generate_decrypt_word
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subi r4,r4,32
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subi r5,r5,1
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cmpwi r5,0
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bt gt,ppc_generate_decrypt_block
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blr
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