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Felipe Moura
ce645060fa
The existing CRYPTO_AES_CTR is the RFC 3686 profile: the last 4 bytes of the key are a nonce, the IV is 8 bytes and only the low 32 bits of the counter block are incremented. SSH aes128/192/256-ctr (RFC 4344) instead uses the key as-is (no embedded nonce) and treats the whole 16-byte IV as the initial counter block, incremented as a 128-bit big-endian integer, with the first keystream block being E(IV). Add CRYPTO_AES_CTR_SSH as a new enc_xform mirroring the CRYPTO_CHACHA20_DJB addition. It reuses struct aes_ctr_ctx and the AES block; only setkey (full key, no nonce), reinit (full 16-byte counter) and crypt (encrypt-then- increment over all 16 bytes) differ from the RFC 3686 variant. Keystream validated against `openssl enc -aes-128-ctr`, including a counter that carries across byte boundaries and a non-block-aligned tail. Signed-off-by: Felipe Moura <moura.fmo@gmail.com>