lib/mbedtls
1
0
Fork 0
mirror of https://github.com/Mbed-TLS/mbedtls.git synced 2025-07-29 11:41:15 +03:00
Code Activity

mbedtls_ecp_write_key: document and test larger output buffer

Browse Source 
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
This commit is contained in:
Gilles Peskine
2024-02-19 13:30:31 +01:00
parent 5bb04e03ac
commit a395bdd066
3 changed files with 130 additions and 2 deletions
Download Patch File Download Diff File Expand all files Collapse all files

21
include/mbedtls/ecp.h
View File

@ -1330,11 +1330,28 @@ int mbedtls_ecp_read_key(mbedtls_ecp_group_id grp_id, mbedtls_ecp_keypair *key,
/**
* \brief This function exports an elliptic curve private key.
*
* \note Note that although this function accepts an output
* buffer that is larger than the key, most key import
* interfaces require the output to be trimmed to the
* key's nominal length. It is generally simplest to
* pass the key's nominal length as \c buflen, after
* checking that the output buffer is large enough.
* See the description of the \p buflen parameter for
* how to calculate the nominal length.
*
* \param key The private key.
* \param buf The output buffer for containing the binary representation
* of the key. (Big endian integer for Weierstrass curves, byte
* string for Montgomery curves.)
* of the key.
* For Weierstrass curves, this is the big-endian
* representation, padded with null bytes at the beginning
* to reach \p buflen bytes.
* For Montgomery curves, this is the standard byte string
* representation (which is little-endian), padded with
* null bytes at the end to reach \p buflen bytes.
* \param buflen The total length of the buffer in bytes.
* The length of the output is always
* (`grp->nbits` + 7) / 8 bytes
* where `grp->nbits` is the private key size in bits.
*
* \return \c 0 on success.
* \return #MBEDTLS_ERR_ECP_BUFFER_TOO_SMALL if the \p key