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-rw-r--r--include/crypto/ecdh.h58
1 files changed, 58 insertions, 0 deletions
diff --git a/include/crypto/ecdh.h b/include/crypto/ecdh.h
index 84bad548d194..03a64f62ba7a 100644
--- a/include/crypto/ecdh.h
+++ b/include/crypto/ecdh.h
@@ -13,18 +13,76 @@
#ifndef _CRYPTO_ECDH_
#define _CRYPTO_ECDH_
+/**
+ * DOC: ECDH Helper Functions
+ *
+ * To use ECDH with the KPP cipher API, the following data structure and
+ * functions should be used.
+ *
+ * The ECC curves known to the ECDH implementation are specified in this
+ * header file.
+ *
+ * To use ECDH with KPP, the following functions should be used to operate on
+ * an ECDH private key. The packet private key that can be set with
+ * the KPP API function call of crypto_kpp_set_secret.
+ */
+
/* Curves IDs */
#define ECC_CURVE_NIST_P192 0x0001
#define ECC_CURVE_NIST_P256 0x0002
+/**
+ * struct ecdh - define an ECDH private key
+ *
+ * @curve_id: ECC curve the key is based on.
+ * @key: Private ECDH key
+ * @key_size: Size of the private ECDH key
+ */
struct ecdh {
unsigned short curve_id;
char *key;
unsigned short key_size;
};
+/**
+ * crypto_ecdh_key_len() - Obtain the size of the private ECDH key
+ * @params: private ECDH key
+ *
+ * This function returns the packet ECDH key size. A caller can use that
+ * with the provided ECDH private key reference to obtain the required
+ * memory size to hold a packet key.
+ *
+ * Return: size of the key in bytes
+ */
int crypto_ecdh_key_len(const struct ecdh *params);
+
+/**
+ * crypto_ecdh_encode_key() - encode the private key
+ * @buf: Buffer allocated by the caller to hold the packet ECDH
+ * private key. The buffer should be at least crypto_ecdh_key_len
+ * bytes in size.
+ * @len: Length of the packet private key buffer
+ * @p: Buffer with the caller-specified private key
+ *
+ * The ECDH implementations operate on a packet representation of the private
+ * key.
+ *
+ * Return: -EINVAL if buffer has insufficient size, 0 on success
+ */
int crypto_ecdh_encode_key(char *buf, unsigned int len, const struct ecdh *p);
+
+/**
+ * crypto_ecdh_decode_key() - decode a private key
+ * @buf: Buffer holding a packet key that should be decoded
+ * @len: Lenth of the packet private key buffer
+ * @p: Buffer allocated by the caller that is filled with the
+ * unpacket ECDH private key.
+ *
+ * The unpacking obtains the private key by pointing @p to the correct location
+ * in @buf. Thus, both pointers refer to the same memory.
+ *
+ * Return: -EINVAL if buffer has insufficient size, 0 on success
+ */
int crypto_ecdh_decode_key(const char *buf, unsigned int len, struct ecdh *p);
#endif