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authorArd Biesheuvel <ard.biesheuvel@linaro.org>2019-07-02 21:41:22 +0200
committerHerbert Xu <herbert@gondor.apana.org.au>2019-07-26 14:55:33 +1000
commite59c1c98745637796df824c0177f279b6e9cad94 (patch)
tree7cd4e284c1634defc73581c5ac879cb17bb2c907 /include/crypto/aes.h
parentcrypto: aes/fixed-time - align key schedule with other implementations (diff)
downloadlinux-dev-e59c1c98745637796df824c0177f279b6e9cad94.tar.xz
linux-dev-e59c1c98745637796df824c0177f279b6e9cad94.zip
crypto: aes - create AES library based on the fixed time AES code
Take the existing small footprint and mostly time invariant C code and turn it into a AES library that can be used for non-performance critical, casual use of AES, and as a fallback for, e.g., SIMD code that needs a secondary path that can be taken in contexts where the SIMD unit is off limits (e.g., in hard interrupts taken from kernel context) Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Diffstat (limited to '')
-rw-r--r--include/crypto/aes.h34
1 files changed, 34 insertions, 0 deletions
diff --git a/include/crypto/aes.h b/include/crypto/aes.h
index 0fdb542c70cd..d0067fca0cd0 100644
--- a/include/crypto/aes.h
+++ b/include/crypto/aes.h
@@ -37,4 +37,38 @@ int crypto_aes_set_key(struct crypto_tfm *tfm, const u8 *in_key,
unsigned int key_len);
int crypto_aes_expand_key(struct crypto_aes_ctx *ctx, const u8 *in_key,
unsigned int key_len);
+
+/**
+ * aes_expandkey - Expands the AES key as described in FIPS-197
+ * @ctx: The location where the computed key will be stored.
+ * @in_key: The supplied key.
+ * @key_len: The length of the supplied key.
+ *
+ * Returns 0 on success. The function fails only if an invalid key size (or
+ * pointer) is supplied.
+ * The expanded key size is 240 bytes (max of 14 rounds with a unique 16 bytes
+ * key schedule plus a 16 bytes key which is used before the first round).
+ * The decryption key is prepared for the "Equivalent Inverse Cipher" as
+ * described in FIPS-197. The first slot (16 bytes) of each key (enc or dec) is
+ * for the initial combination, the second slot for the first round and so on.
+ */
+int aes_expandkey(struct crypto_aes_ctx *ctx, const u8 *in_key,
+ unsigned int key_len);
+
+/**
+ * aes_encrypt - Encrypt a single AES block
+ * @ctx: Context struct containing the key schedule
+ * @out: Buffer to store the ciphertext
+ * @in: Buffer containing the plaintext
+ */
+void aes_encrypt(const struct crypto_aes_ctx *ctx, u8 *out, const u8 *in);
+
+/**
+ * aes_decrypt - Decrypt a single AES block
+ * @ctx: Context struct containing the key schedule
+ * @out: Buffer to store the plaintext
+ * @in: Buffer containing the ciphertext
+ */
+void aes_decrypt(const struct crypto_aes_ctx *ctx, u8 *out, const u8 *in);
+
#endif