RFR: 8326609: New AES implementation with updates specified in FIPS 197 [v5]

[Valerie Peng]

On Wed, 15 Oct 2025 23:04:10 GMT, Shawn M Emery <duke at openjdk.org> wrote:

>> General:
>> -----------
>> i) This work is to replace the existing AES cipher under the Cryptix license.
>> 
>> ii) The lookup tables are employed for performance, but also for operating in constant time.
>> 
>> iii) Several loops have been unrolled for optimization purposes, but are harder to read and don't meet coding style guidelines.
>> 
>> iv) None of the AES related intrinsics has been modified in this PR, but the new code has been updated to use the intrinsics related hooks for the AES block and key table arguments.
>> 
>> Note: I've purposefully not seen the original Cryptix code, so when making a code review comment please don't quote the code in the AESCrypt.java file.
>> 
>> Correctness:
>> -----------------
>> The following AES-specific regression tests have passed in intrinsics (default) and non-intrinsic (-Xint) modes:
>> 
>> i) test/jdk/com/sun/crypto/provider/Cipher/AES: all 27 tests pass
>> 
>> -intrinsics mode for:
>> 
>> ii) test/hotspot/jtreg/compiler/codegen/aes: all 4 tests pass
>> 
>> iii) jck:api/java_security, jck:api/javax_crypto, jck:api/javax_net, jck:api/javax_security, jck:api/org_ietf, and jck:api/javax_xml/crypto: passed, with 10 known failures
>> 
>> iv) jdk_security_infra: passed, with 48 known failures
>> 
>> v) tier1 and tier2: all 110257 tests pass
>> 
>> Security:
>> -----------
>> In order to prevent side-channel (timing and differential power analysis) attacks the code has been constructed to operate in constant time and does not use conditionals based on the key or key expansion table.  This is accomplished by using lookup tables in both the cipher and inverse cipher of AES.
>> 
>> Performance:
>> ------------------
>> All AES related benchmarks have been executed against the new and original Cryptix code:
>> 
>> micro:org.openjdk.bench.javax.crypto.AES
>> 
>> micro:org.openjdk.bench.javax.crypto.full.AESBench
>> 
>> micro:org.openjdk.bench.javax.crypto.full.AESExtraBench
>> 
>> micro:org.openjdk.bench.javax.crypto.full.AESGCMBench
>> 
>> micro:org.openjdk.bench.javax.crypto.full.AESGCMByteBuffer
>> 
>> micro:org.openjdk.bench.javax.crypto.full.AESGCMCipherInputStream
>> 
>> micro:org.openjdk.bench.javax.crypto.full.AESGCMCipherOutputStream
>> 
>> micro:org.openjdk.bench.javax.crypto.full.AESKeyWrapBench.
>> 
>> micro:org.openjdk.bench.java.security.CipherSuiteBench (AES)
>> 
>> The benchmarks were executed in different compiler modes (default (no compiler options), -Xint, and -Xcomp) and on two different architectures (x86 and arm64) with the following encryption re...
>
> Shawn M Emery has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Updates for code review comments from @valeriepeng

src/java.base/share/classes/com/sun/crypto/provider/AES_Crypt.java line 954:

> 952:             }
> 953:             w[i] = w[i - nk] ^ tmp;
> 954:         }

Looks like most of these local variables can be removed? Since you are not changing the value of `len`, you can just use `WB`. `rW` is only used inside the if-block from line 944-948, so it can be declared on line 945.  Line 946-948 can be merged on one line, e.g. `tmp = subByte(rW, SBOX) ^ RCON[(i / nk) - 1];` and no need for `subWord` and `g`. Same goes for line 950 and 951.
Also, the value of `WB * (rounds + 1)` is used twice, this can be stored in a local variable say `wLen`, so it's only calculated once.
Same goes for the `i * WB` value from line 937-940

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PR Review Comment: https://git.openjdk.org/jdk/pull/27807#discussion_r2434276514