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Ive spent about 10 hours benchmarking permutations on our counter-mode implementation. This is the one that flies. (Avoid OpenSSL; optimizze rijndael calling convention to avoid needing to marshall and unmarshall counter.) This should speed up cell encryption by about 27%.
svn:r5486
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@ -30,14 +30,14 @@ const char aes_c_id[] = "$Id$";
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#include <openssl/evp.h>
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#endif
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/* For now, if OpenSSL supports AES, we always use the EVP_CIPHER_CTX version
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* of it, so OpenSSL can use an engine instead if available. If the overhead
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* turns out to suck, we should maybe switch to use OpenSSL's AES directly
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* when no engine exists.
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/* Benchmarking suggests that using the built-in rijndael below is
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* significantly faster than using OpenSSL's EVP code (by about 27%)
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* and faster than using OpenSSL's AES functions (by about 19%).
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* The counter-mode optimization saves around 5%.
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*/
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#ifdef USE_OPENSSL_AES
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#define USE_OPENSSL_EVP
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#endif
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#undef USE_OPENSSL_AES
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#undef USE_OPENSSL_EVP
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#define USE_RIJNDAEL_COUNTER_OPTIMIZATION
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/*======================================================================*/
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/* From rijndael-alg-fst.h */
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@ -52,8 +52,12 @@ typedef uint8_t u8;
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#define MAXNR 14
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static int rijndaelKeySetupEnc(u32 rk[/*4*(Nr + 1)*/], const u8 cipherKey[], int keyBits);
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#ifdef USE_RIJNDAEL_COUNTER_OPTIMIZATION
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static void rijndaelEncrypt(const u32 rk[/*4*(Nr + 1)*/], int Nr, u32 ctr1, u32 ctr0, u8 ct[16]);
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#else
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static void rijndaelEncrypt(const u32 rk[/*4*(Nr + 1)*/], int Nr, const u8 pt[16], u8 ct[16]);
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#endif
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#endif
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/*======================================================================*/
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/* Interface to AES code, and counter implementation */
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@ -77,7 +81,7 @@ struct aes_cnt_cipher {
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* Helper function: set <b>cipher</b>'s internal buffer to the encrypted
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* value of the current counter.
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*/
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static void
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static INLINE void
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_aes_fill_buf(aes_cnt_cipher_t *cipher)
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{
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/* We don't currently use OpenSSL's counter mode implementation because:
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@ -86,6 +90,9 @@ _aes_fill_buf(aes_cnt_cipher_t *cipher)
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* 3) changing the counter position was not trivial, last time I looked.
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* None of these issues are insurmountable in principle.
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*/
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#if !defined(USE_OPENSSL_EVP) && !defined(USE_OPENSSL_AES) && defined(USE_RIJNDAEL_COUNTER_OPTIMIZATION)
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rijndaelEncrypt(cipher->rk, cipher->nr, cipher->counter1, cipher->counter0, cipher->buf);
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#else
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u32 counter0 = cipher->counter0;
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u32 counter1 = cipher->counter1;
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u8 buf[16];
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@ -109,6 +116,7 @@ _aes_fill_buf(aes_cnt_cipher_t *cipher)
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#else
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rijndaelEncrypt(cipher->rk, cipher->nr, buf, cipher->buf);
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#endif
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#endif
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}
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/**
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@ -694,8 +702,13 @@ rijndaelKeySetupEnc(u32 rk[/*4*(Nr + 1)*/], const u8 cipherKey[], int keyBits)
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return 0;
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}
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#ifdef USE_RIJNDAEL_COUNTER_OPTIMIZATION
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void
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rijndaelEncrypt(const u32 rk[/*4*(Nr + 1)*/], int Nr, u32 ctr1, u32 ctr0, u8 ct[16])
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#else
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void
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rijndaelEncrypt(const u32 rk[/*4*(Nr + 1)*/], int Nr, const u8 pt[16], u8 ct[16])
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#endif
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{
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u32 s0, s1, s2, s3, t0, t1, t2, t3;
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#ifndef FULL_UNROLL
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@ -706,10 +719,18 @@ rijndaelEncrypt(const u32 rk[/*4*(Nr + 1)*/], int Nr, const u8 pt[16], u8 ct[16]
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* map byte array block to cipher state
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* and add initial round key:
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*/
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#ifdef USE_RIJNDAEL_COUNTER_OPTIMIZATION
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s0 = rk[0];
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s1 = rk[1];
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s2 = ctr1 ^ rk[2];
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s3 = ctr0 ^ rk[3];
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#else
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s0 = GETU32(pt ) ^ rk[0];
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s1 = GETU32(pt + 4) ^ rk[1];
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s2 = GETU32(pt + 8) ^ rk[2];
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s3 = GETU32(pt + 12) ^ rk[3];
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#endif
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#ifdef FULL_UNROLL
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/* round 1: */
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t0 = Te0[s0 >> 24] ^ Te1[(s1 >> 16) & 0xff] ^ Te2[(s2 >> 8) & 0xff] ^ Te3[s3 & 0xff] ^ rk[ 4];
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