crypto: chacha20-generic - add XChaCha20 support

[linux.git] / include / crypto / chacha20.h

diff --git a/include/crypto/chacha20.h b/include/crypto/chacha20.h
index f76302d99e2bedbdb0be35c202cd8a8b24c3a6a6..c24b4ac03b8564cead7dd19c81f383598d337621 100644 (file)
--- a/include/crypto/chacha20.h
+++ b/include/crypto/chacha20.h
@@ -1,6 +1,10 @@
 /* SPDX-License-Identifier: GPL-2.0 */
 /*
- * Common values for the ChaCha20 algorithm
+ * Common values and helper functions for the ChaCha20 and XChaCha20 algorithms.
+ *
+ * XChaCha20 extends ChaCha20's nonce to 192 bits, while provably retaining
+ * ChaCha20's security.  Here they share the same key size, tfm context, and
+ * setkey function; only their IV size and encrypt/decrypt function differ.
  */
 
 #ifndef _CRYPTO_CHACHA20_H
@@ -10,18 +14,29 @@
 #include <linux/types.h>
 #include <linux/crypto.h>
 
+/* 32-bit stream position, then 96-bit nonce (RFC7539 convention) */
 #define CHACHA20_IV_SIZE       16
+
 #define CHACHA20_KEY_SIZE      32
 #define CHACHA20_BLOCK_SIZE    64
+#define CHACHAPOLY_IV_SIZE     12
+
+/* 192-bit nonce, then 64-bit stream position */
+#define XCHACHA20_IV_SIZE      32
 
 struct chacha20_ctx {
        u32 key[8];
 };
 
 void chacha20_block(u32 *state, u8 *stream);
+void hchacha20_block(const u32 *in, u32 *out);
+
 void crypto_chacha20_init(u32 *state, struct chacha20_ctx *ctx, u8 *iv);
+
 int crypto_chacha20_setkey(struct crypto_skcipher *tfm, const u8 *key,
                           unsigned int keysize);
+
 int crypto_chacha20_crypt(struct skcipher_request *req);
+int crypto_xchacha20_crypt(struct skcipher_request *req);
 
 #endif