diff --git a/include/mbedtls/rsa.h b/include/mbedtls/rsa.h
index 6a31514..41a00a9 100644
--- a/include/mbedtls/rsa.h
+++ b/include/mbedtls/rsa.h
@@ -1013,6 +1013,72 @@
  *                 buffer of length \p hashlen Bytes. If \p md_alg is not
  *                 #MBEDTLS_MD_NONE, it must be a readable buffer of length
  *                 the size of the hash corresponding to \p md_alg.
+ * \param saltlen  The length of the salt that should be used.
+ *                 If passed MBEDTLS_RSA_SALT_LEN_ANY, the function will use
+ *                 the largest possible salt length.
+ * \param sig      The buffer to hold the signature. This must be a writable
+ *                 buffer of length \c ctx->len Bytes. For example, \c 256 Bytes
+ *                 for an 2048-bit RSA modulus. A buffer length of
+ *                 #MBEDTLS_MPI_MAX_SIZE is always safe.
+ *
+ * \return         \c 0 if the signing operation was successful.
+ * \return         An \c MBEDTLS_ERR_RSA_XXX error code on failure.
+ */
+int mbedtls_rsa_rsassa_pss_sign_ext( mbedtls_rsa_context *ctx,
+                         int (*f_rng)(void *, unsigned char *, size_t),
+                         void *p_rng,
+                         int mode,
+                         mbedtls_md_type_t md_alg,
+                         unsigned int hashlen,
+                         const unsigned char *hash,
+                         int saltlen,
+                         unsigned char *sig );
+
+/**
+ * \brief          This function performs a PKCS#1 v2.1 PSS signature
+ *                 operation (RSASSA-PSS-SIGN).
+ *
+ * \note           The \p hash_id in the RSA context is the one used for the
+ *                 encoding. \p md_alg in the function call is the type of hash
+ *                 that is encoded. According to <em>RFC-3447: Public-Key
+ *                 Cryptography Standards (PKCS) #1 v2.1: RSA Cryptography
+ *                 Specifications</em> it is advised to keep both hashes the
+ *                 same.
+ *
+ * \note           This function always uses the maximum possible salt size,
+ *                 up to the length of the payload hash. This choice of salt
+ *                 size complies with FIPS 186-4 §5.5 (e) and RFC 8017 (PKCS#1
+ *                 v2.2) §9.1.1 step 3. Furthermore this function enforces a
+ *                 minimum salt size which is the hash size minus 2 bytes. If
+ *                 this minimum size is too large given the key size (the salt
+ *                 size, plus the hash size, plus 2 bytes must be no more than
+ *                 the key size in bytes), this function returns
+ *                 #MBEDTLS_ERR_RSA_BAD_INPUT_DATA.
+ *
+ * \deprecated     It is deprecated and discouraged to call this function
+ *                 in #MBEDTLS_RSA_PUBLIC mode. Future versions of the library
+ *                 are likely to remove the \p mode argument and have it
+ *                 implicitly set to #MBEDTLS_RSA_PRIVATE.
+ *
+ * \note           Alternative implementations of RSA need not support
+ *                 mode being set to #MBEDTLS_RSA_PUBLIC and might instead
+ *                 return #MBEDTLS_ERR_PLATFORM_FEATURE_UNSUPPORTED.
+ *
+ * \param ctx      The initialized RSA context to use.
+ * \param f_rng    The RNG function. It must not be \c NULL.
+ * \param p_rng    The RNG context to be passed to \p f_rng. This may be \c NULL
+ *                 if \p f_rng doesn't need a context argument.
+ * \param mode     The mode of operation. This must be either
+ *                 #MBEDTLS_RSA_PRIVATE or #MBEDTLS_RSA_PUBLIC (deprecated).
+ * \param md_alg   The message-digest algorithm used to hash the original data.
+ *                 Use #MBEDTLS_MD_NONE for signing raw data.
+ * \param hashlen  The length of the message digest.
+ *                 Ths is only used if \p md_alg is #MBEDTLS_MD_NONE.
+ * \param hash     The buffer holding the message digest or raw data.
+ *                 If \p md_alg is #MBEDTLS_MD_NONE, this must be a readable
+ *                 buffer of length \p hashlen Bytes. If \p md_alg is not
+ *                 #MBEDTLS_MD_NONE, it must be a readable buffer of length
+ *                 the size of the hash corresponding to \p md_alg.
  * \param sig      The buffer to hold the signature. This must be a writable
  *                 buffer of length \c ctx->len Bytes. For example, \c 256 Bytes
  *                 for an 2048-bit RSA modulus. A buffer length of