1 files changed, 54 insertions, 0 deletions
diff --git a/include/crypto/chacha.h b/include/crypto/chacha.h
new file mode 100644
index 000000000000..1fc70a69d550
--- /dev/null
+++ b/include/crypto/chacha.h
@@ -0,0 +1,54 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Common values and helper functions for the ChaCha and XChaCha stream ciphers.
+ *
+ * XChaCha extends ChaCha's nonce to 192 bits, while provably retaining ChaCha's
+ * security.  Here they share the same key size, tfm context, and setkey
+ * function; only their IV size and encrypt/decrypt function differ.
+ *
+ * The ChaCha paper specifies 20, 12, and 8-round variants.  In general, it is
+ * recommended to use the 20-round variant ChaCha20.  However, the other
+ * variants can be needed in some performance-sensitive scenarios.  The generic
+ * ChaCha code currently allows only the 20 and 12-round variants.
+ */
+
+#ifndef _CRYPTO_CHACHA_H
+#define _CRYPTO_CHACHA_H
+
+#include <crypto/skcipher.h>
+#include <linux/types.h>
+#include <linux/crypto.h>
+
+/* 32-bit stream position, then 96-bit nonce (RFC7539 convention) */
+#define CHACHA_IV_SIZE		16
+
+#define CHACHA_KEY_SIZE		32
+#define CHACHA_BLOCK_SIZE	64
+#define CHACHAPOLY_IV_SIZE	12
+
+/* 192-bit nonce, then 64-bit stream position */
+#define XCHACHA_IV_SIZE		32
+
+struct chacha_ctx {
+	u32 key[8];
+	int nrounds;
+};
+
+void chacha_block(u32 *state, u8 *stream, int nrounds);
+static inline void chacha20_block(u32 *state, u8 *stream)
+{
+	chacha_block(state, stream, 20);
+}
+void hchacha_block(const u32 *in, u32 *out, int nrounds);
+
+void crypto_chacha_init(u32 *state, struct chacha_ctx *ctx, u8 *iv);
+
+int crypto_chacha20_setkey(struct crypto_skcipher *tfm, const u8 *key,
+			   unsigned int keysize);
+int crypto_chacha12_setkey(struct crypto_skcipher *tfm, const u8 *key,
+			   unsigned int keysize);
+
+int crypto_chacha_crypt(struct skcipher_request *req);
+int crypto_xchacha_crypt(struct skcipher_request *req);
+
+#endif /* _CRYPTO_CHACHA_H */