diff --git a/include/mbedtls/md.h b/include/mbedtls/md.h
index 1fa22f5..a142903 100644
--- a/include/mbedtls/md.h
+++ b/include/mbedtls/md.h
@@ -1,7 +1,8 @@
 /**
  * \file md.h
  *
- * \brief This file contains the generic message-digest wrapper.
+ * \brief   This file contains the generic functions for message-digest
+ *          (hashing) and HMAC.
  *
  * \author Adriaan de Jong <dejong@fox-it.com>
  */
@@ -31,6 +32,93 @@
 #include "mbedtls/build_info.h"
 #include "mbedtls/platform_util.h"
 
+#if defined(MBEDTLS_MD_LIGHT)
+
+/*
+ * - MBEDTLS_MD_CAN_xxx is defined if the md module can perform xxx.
+ * - MBEDTLS_MD_xxx_VIA_PSA is defined if the md module may perform xxx via PSA
+ *   (see below).
+ * - MBEDTLS_MD_SOME_PSA is defined if at least one algorithm may be performed
+ *   via PSA (see below).
+ * - MBEDTLS_MD_SOME_LEGACY is defined if at least one algorithm may be performed
+ *   via a direct legacy call (see below).
+ *
+ * The md module performs an algorithm via PSA if there is a PSA hash
+ * accelerator and the PSA driver subsytem is initialized at the time the
+ * operation is started, and makes a direct legacy call otherwise.
+ */
+
+/* PSA accelerated implementations */
+#if defined(MBEDTLS_PSA_CRYPTO_C)
+#if defined(MBEDTLS_PSA_ACCEL_ALG_MD5)
+#define MBEDTLS_MD_CAN_MD5
+#define MBEDTLS_MD_MD5_VIA_PSA
+#define MBEDTLS_MD_SOME_PSA
+#endif
+#if defined(MBEDTLS_PSA_ACCEL_ALG_SHA_1)
+#define MBEDTLS_MD_CAN_SHA1
+#define MBEDTLS_MD_SHA1_VIA_PSA
+#define MBEDTLS_MD_SOME_PSA
+#endif
+#if defined(MBEDTLS_PSA_ACCEL_ALG_SHA_224)
+#define MBEDTLS_MD_CAN_SHA224
+#define MBEDTLS_MD_SHA224_VIA_PSA
+#define MBEDTLS_MD_SOME_PSA
+#endif
+#if defined(MBEDTLS_PSA_ACCEL_ALG_SHA_256)
+#define MBEDTLS_MD_CAN_SHA256
+#define MBEDTLS_MD_SHA256_VIA_PSA
+#define MBEDTLS_MD_SOME_PSA
+#endif
+#if defined(MBEDTLS_PSA_ACCEL_ALG_SHA_384)
+#define MBEDTLS_MD_CAN_SHA384
+#define MBEDTLS_MD_SHA384_VIA_PSA
+#define MBEDTLS_MD_SOME_PSA
+#endif
+#if defined(MBEDTLS_PSA_ACCEL_ALG_SHA_512)
+#define MBEDTLS_MD_CAN_SHA512
+#define MBEDTLS_MD_SHA512_VIA_PSA
+#define MBEDTLS_MD_SOME_PSA
+#endif
+#if defined(MBEDTLS_PSA_ACCEL_ALG_RIPEMD160)
+#define MBEDTLS_MD_CAN_RIPEMD160
+#define MBEDTLS_MD_RIPEMD160_VIA_PSA
+#define MBEDTLS_MD_SOME_PSA
+#endif
+#endif /* MBEDTLS_PSA_CRYPTO_C */
+
+/* Built-in implementations */
+#if defined(MBEDTLS_MD5_C)
+#define MBEDTLS_MD_CAN_MD5
+#define MBEDTLS_MD_SOME_LEGACY
+#endif
+#if defined(MBEDTLS_SHA1_C)
+#define MBEDTLS_MD_CAN_SHA1
+#define MBEDTLS_MD_SOME_LEGACY
+#endif
+#if defined(MBEDTLS_SHA224_C)
+#define MBEDTLS_MD_CAN_SHA224
+#define MBEDTLS_MD_SOME_LEGACY
+#endif
+#if defined(MBEDTLS_SHA256_C)
+#define MBEDTLS_MD_CAN_SHA256
+#define MBEDTLS_MD_SOME_LEGACY
+#endif
+#if defined(MBEDTLS_SHA384_C)
+#define MBEDTLS_MD_CAN_SHA384
+#define MBEDTLS_MD_SOME_LEGACY
+#endif
+#if defined(MBEDTLS_SHA512_C)
+#define MBEDTLS_MD_CAN_SHA512
+#define MBEDTLS_MD_SOME_LEGACY
+#endif
+#if defined(MBEDTLS_RIPEMD160_C)
+#define MBEDTLS_MD_CAN_RIPEMD160
+#define MBEDTLS_MD_SOME_LEGACY
+#endif
+
+#endif /* MBEDTLS_MD_LIGHT */
+
 /** The selected feature is not available. */
 #define MBEDTLS_ERR_MD_FEATURE_UNAVAILABLE                -0x5080
 /** Bad input parameters to function. */
@@ -67,21 +155,22 @@
     MBEDTLS_MD_SHA3_512,    /**< The SHA3-512 message digest. */
 } mbedtls_md_type_t;
 
-#if defined(MBEDTLS_SHA512_C) || defined(MBEDTLS_SHA3_C)
+#if defined(MBEDTLS_MD_CAN_SHA512) || defined(MBEDTLS_SHA3_C)
 #define MBEDTLS_MD_MAX_SIZE         64  /* longest known is SHA512 */
-#elif defined(MBEDTLS_SHA384_C)
+#elif defined(MBEDTLS_MD_CAN_SHA384)
 #define MBEDTLS_MD_MAX_SIZE         48  /* longest known is SHA384 */
-#elif defined(MBEDTLS_SHA256_C)
+#elif defined(MBEDTLS_MD_CAN_SHA256)
 #define MBEDTLS_MD_MAX_SIZE         32  /* longest known is SHA256 */
-#elif defined(MBEDTLS_SHA224_C)
+#elif defined(MBEDTLS_MD_CAN_SHA224)
 #define MBEDTLS_MD_MAX_SIZE         28  /* longest known is SHA224 */
 #else
-#define MBEDTLS_MD_MAX_SIZE         20  /* longest known is SHA1 or RIPE MD-160 */
+#define MBEDTLS_MD_MAX_SIZE         20  /* longest known is SHA1 or RIPE MD-160
+                                           or smaller (MD5 and earlier) */
 #endif
 
 #if defined(MBEDTLS_SHA3_C)
 #define MBEDTLS_MD_MAX_BLOCK_SIZE         144 /* the longest known is SHA3-224 */
-#elif defined(MBEDTLS_SHA512_C)
+#elif defined(MBEDTLS_MD_CAN_SHA512)
 #define MBEDTLS_MD_MAX_BLOCK_SIZE         128
 #else
 #define MBEDTLS_MD_MAX_BLOCK_SIZE         64
@@ -100,44 +189,37 @@
 typedef struct mbedtls_md_info_t mbedtls_md_info_t;
 
 /**
+ * Used internally to indicate whether a context uses legacy or PSA.
+ *
+ * Internal use only.
+ */
+typedef enum {
+    MBEDTLS_MD_ENGINE_LEGACY = 0,
+    MBEDTLS_MD_ENGINE_PSA,
+} mbedtls_md_engine_t;
+
+/**
  * The generic message-digest context.
  */
 typedef struct mbedtls_md_context_t {
     /** Information about the associated message digest. */
     const mbedtls_md_info_t *MBEDTLS_PRIVATE(md_info);
 
-    /** The digest-specific context. */
+#if defined(MBEDTLS_MD_SOME_PSA)
+    /** Are hash operations dispatched to PSA or legacy? */
+    mbedtls_md_engine_t MBEDTLS_PRIVATE(engine);
+#endif
+
+    /** The digest-specific context (legacy) or the PSA operation. */
     void *MBEDTLS_PRIVATE(md_ctx);
 
+#if defined(MBEDTLS_MD_C)
     /** The HMAC part of the context. */
     void *MBEDTLS_PRIVATE(hmac_ctx);
+#endif
 } mbedtls_md_context_t;
 
 /**
- * \brief           This function returns the list of digests supported by the
- *                  generic digest module.
- *
- * \note            The list starts with the strongest available hashes.
- *
- * \return          A statically allocated array of digests. Each element
- *                  in the returned list is an integer belonging to the
- *                  message-digest enumeration #mbedtls_md_type_t.
- *                  The last entry is 0.
- */
-const int *mbedtls_md_list(void);
-
-/**
- * \brief           This function returns the message-digest information
- *                  associated with the given digest name.
- *
- * \param md_name   The name of the digest to search for.
- *
- * \return          The message-digest information associated with \p md_name.
- * \return          NULL if the associated message-digest information is not found.
- */
-const mbedtls_md_info_t *mbedtls_md_info_from_string(const char *md_name);
-
-/**
  * \brief           This function returns the message-digest information
  *                  associated with the given digest type.
  *
@@ -149,19 +231,6 @@
 const mbedtls_md_info_t *mbedtls_md_info_from_type(mbedtls_md_type_t md_type);
 
 /**
- * \brief           This function returns the message-digest information
- *                  from the given context.
- *
- * \param ctx       The context from which to extract the information.
- *                  This must be initialized (or \c NULL).
- *
- * \return          The message-digest information associated with \p ctx.
- * \return          \c NULL if \p ctx is \c NULL.
- */
-const mbedtls_md_info_t *mbedtls_md_info_from_ctx(
-    const mbedtls_md_context_t *ctx);
-
-/**
  * \brief           This function initializes a message-digest context without
  *                  binding it to a particular message-digest algorithm.
  *
@@ -227,6 +296,10 @@
  *
  * \return          \c 0 on success.
  * \return          #MBEDTLS_ERR_MD_BAD_INPUT_DATA on parameter-verification failure.
+ * \return          #MBEDTLS_ERR_MD_FEATURE_UNAVAILABLE if both contexts are
+ *                  not using the same engine. This can be avoided by moving
+ *                  the call to psa_crypto_init() before the first call to
+ *                  mbedtls_md_setup().
  */
 MBEDTLS_CHECK_RETURN_TYPICAL
 int mbedtls_md_clone(mbedtls_md_context_t *dst,
@@ -255,17 +328,6 @@
 mbedtls_md_type_t mbedtls_md_get_type(const mbedtls_md_info_t *md_info);
 
 /**
- * \brief           This function extracts the message-digest name from the
- *                  message-digest information structure.
- *
- * \param md_info   The information structure of the message-digest algorithm
- *                  to use.
- *
- * \return          The name of the message digest.
- */
-const char *mbedtls_md_get_name(const mbedtls_md_info_t *md_info);
-
-/**
  * \brief           This function starts a message-digest computation.
  *
  *                  You must call this function after setting up the context
@@ -343,6 +405,54 @@
 int mbedtls_md(const mbedtls_md_info_t *md_info, const unsigned char *input, size_t ilen,
                unsigned char *output);
 
+/**
+ * \brief           This function returns the list of digests supported by the
+ *                  generic digest module.
+ *
+ * \note            The list starts with the strongest available hashes.
+ *
+ * \return          A statically allocated array of digests. Each element
+ *                  in the returned list is an integer belonging to the
+ *                  message-digest enumeration #mbedtls_md_type_t.
+ *                  The last entry is 0.
+ */
+const int *mbedtls_md_list(void);
+
+/**
+ * \brief           This function returns the message-digest information
+ *                  associated with the given digest name.
+ *
+ * \param md_name   The name of the digest to search for.
+ *
+ * \return          The message-digest information associated with \p md_name.
+ * \return          NULL if the associated message-digest information is not found.
+ */
+const mbedtls_md_info_t *mbedtls_md_info_from_string(const char *md_name);
+
+/**
+ * \brief           This function extracts the message-digest name from the
+ *                  message-digest information structure.
+ *
+ * \param md_info   The information structure of the message-digest algorithm
+ *                  to use.
+ *
+ * \return          The name of the message digest.
+ */
+const char *mbedtls_md_get_name(const mbedtls_md_info_t *md_info);
+
+/**
+ * \brief           This function returns the message-digest information
+ *                  from the given context.
+ *
+ * \param ctx       The context from which to extract the information.
+ *                  This must be initialized (or \c NULL).
+ *
+ * \return          The message-digest information associated with \p ctx.
+ * \return          \c NULL if \p ctx is \c NULL.
+ */
+const mbedtls_md_info_t *mbedtls_md_info_from_ctx(
+    const mbedtls_md_context_t *ctx);
+
 #if defined(MBEDTLS_FS_IO)
 /**
  * \brief          This function calculates the message-digest checksum
@@ -477,10 +587,6 @@
                     const unsigned char *input, size_t ilen,
                     unsigned char *output);
 
-/* Internal use */
-MBEDTLS_CHECK_RETURN_TYPICAL
-int mbedtls_md_process(mbedtls_md_context_t *ctx, const unsigned char *data);
-
 #ifdef __cplusplus
 }
 #endif