diff --git a/ChangeLog.d/require-matching-hashlen-rsa.txt b/ChangeLog.d/require-matching-hashlen-rsa.txt
new file mode 100644
index 0000000..096b577
--- /dev/null
+++ b/ChangeLog.d/require-matching-hashlen-rsa.txt
@@ -0,0 +1,5 @@
+API changes
+   * Signature functions in the RSA and PK modules now require the hash
+     length parameter to be the size of the hash input. For RSA signatures
+     other than raw PKCS#1 v1.5, this must match the output size of the
+     specified hash algorithm.
diff --git a/docs/3.0-migration-guide.d/require-matching-hashlen-rsa.md b/docs/3.0-migration-guide.d/require-matching-hashlen-rsa.md
new file mode 100644
index 0000000..d59a8d3
--- /dev/null
+++ b/docs/3.0-migration-guide.d/require-matching-hashlen-rsa.md
@@ -0,0 +1,24 @@
+Signature functions now require the hash length to match the expected value
+---------------------------------------------------------------------------
+
+This affects users of the PK API as well as users of the low-level API in the RSA module. Users of the PSA API or of the ECDSA module are unaffected.
+
+All the functions in the RSA module that accept a `hashlen` parameter used to
+ignore it unless the `md_alg` parameter was `MBEDTLS_MD_NONE`, indicating raw
+data was signed. The `hashlen` parameter is now always the size that is read
+from the `hash` input buffer. This length must be equal to the output size of
+the hash algorithm used when signing a hash. (The requirements when signing
+raw data are unchanged.) This affects the following functions:
+
+* `mbedtls_rsa_pkcs1_sign`, `mbedtls_rsa_pkcs1_verify`
+* `mbedtls_rsa_rsassa_pkcs1_v15_sign`, `mbedtls_rsa_rsassa_pkcs1_v15_verify`
+* `mbedtls_rsa_rsassa_pss_sign`, `mbedtls_rsa_rsassa_pss_verify`
+* `mbedtls_rsa_rsassa_pss_sign_ext`, `mbedtls_rsa_rsassa_pss_verify_ext`
+
+The signature functions in the PK module no longer accept 0 as the `hash_len` parameter. The `hash_len` parameter is now always the size that is read from the `hash` input buffer. This affects the following functions:
+
+* `mbedtls_pk_sign`, `mbedtls_pk_verify`
+* `mbedtls_pk_sign_restartable`, `mbedtls_pk_verify_restartable`
+* `mbedtls_pk_verify_ext`
+
+The migration path is to pass the correct value to those functions.
diff --git a/include/mbedtls/pk.h b/include/mbedtls/pk.h
index dec5111..ec7fe6e 100644
--- a/include/mbedtls/pk.h
+++ b/include/mbedtls/pk.h
@@ -399,9 +399,17 @@
  * \brief           Verify signature (including padding if relevant).
  *
  * \param ctx       The PK context to use. It must have been set up.
- * \param md_alg    Hash algorithm used (see notes)
+ * \param md_alg    Hash algorithm used.
+ *                  This can be #MBEDTLS_MD_NONE if the signature algorithm
+ *                  does not rely on a hash algorithm (non-deterministic
+ *                  ECDSA, RSA PKCS#1 v1.5).
+ *                  For PKCS#1 v1.5, if \p md_alg is #MBEDTLS_MD_NONE, then
+ *                  \p hash is the DigestInfo structure used by RFC 8017
+ *                  &sect;9.2 steps 3&ndash;6. If \p md_alg is a valid hash
+ *                  algorithm then \p hash is the digest itself, and this
+ *                  function calculates the DigestInfo encoding internally.
  * \param hash      Hash of the message to sign
- * \param hash_len  Hash length or 0 (see notes)
+ * \param hash_len  Hash length
  * \param sig       Signature to verify
  * \param sig_len   Signature length
  *
@@ -413,11 +421,6 @@
  * \note            For RSA keys, the default padding type is PKCS#1 v1.5.
  *                  Use \c mbedtls_pk_verify_ext( MBEDTLS_PK_RSASSA_PSS, ... )
  *                  to verify RSASSA_PSS signatures.
- *
- * \note            If hash_len is 0, then the length associated with md_alg
- *                  is used instead, or an error returned if it is invalid.
- *
- * \note            md_alg may be MBEDTLS_MD_NONE, only if hash_len != 0
  */
 int mbedtls_pk_verify( mbedtls_pk_context *ctx, mbedtls_md_type_t md_alg,
                const unsigned char *hash, size_t hash_len,
@@ -490,7 +493,7 @@
  *                  with a private key.
  * \param md_alg    Hash algorithm used (see notes)
  * \param hash      Hash of the message to sign
- * \param hash_len  Hash length or 0 (see notes)
+ * \param hash_len  Hash length
  * \param sig       Place to write the signature.
  *                  It must have enough room for the signature.
  *                  #MBEDTLS_PK_SIGNATURE_MAX_SIZE is always enough.
@@ -507,9 +510,6 @@
  *                  There is no interface in the PK module to make RSASSA-PSS
  *                  signatures yet.
  *
- * \note            If hash_len is 0, then the length associated with md_alg
- *                  is used instead, or an error returned if it is invalid.
- *
  * \note            For RSA, md_alg may be MBEDTLS_MD_NONE if hash_len != 0.
  *                  For ECDSA, md_alg may never be MBEDTLS_MD_NONE.
  */
@@ -530,7 +530,7 @@
  *                  with a private key.
  * \param md_alg    Hash algorithm used (see notes for mbedtls_pk_sign())
  * \param hash      Hash of the message to sign
- * \param hash_len  Hash length or 0 (see notes for mbedtls_pk_sign())
+ * \param hash_len  Hash length
  * \param sig       Place to write the signature.
  *                  It must have enough room for the signature.
  *                  #MBEDTLS_PK_SIGNATURE_MAX_SIZE is always enough.
diff --git a/include/mbedtls/rsa.h b/include/mbedtls/rsa.h
index c953a89..9a070e7 100644
--- a/include/mbedtls/rsa.h
+++ b/include/mbedtls/rsa.h
@@ -796,13 +796,11 @@
  *                 if \p f_rng doesn't need a context argument.
  * \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 hashlen  The length of the message digest or raw data in Bytes.
+ *                 If \p md_alg is not #MBEDTLS_MD_NONE, this must match the
+ *                 output length of the corresponding hash algorithm.
  * \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.
+ *                 This must be a readable buffer of at least \p hashlen Bytes.
  * \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
@@ -830,13 +828,11 @@
  *                 if \p f_rng doesn't need a context argument.
  * \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 hashlen  The length of the message digest or raw data in Bytes.
+ *                 If \p md_alg is not #MBEDTLS_MD_NONE, this must match the
+ *                 output length of the corresponding hash algorithm.
  * \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.
+ *                 This must be a readable buffer of at least \p hashlen Bytes.
  * \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
@@ -878,13 +874,11 @@
  *                 if \p f_rng doesn't need a context argument.
  * \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 hashlen  The length of the message digest or raw data in Bytes.
+ *                 If \p md_alg is not #MBEDTLS_MD_NONE, this must match the
+ *                 output length of the corresponding hash algorithm.
  * \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.
+ *                 This must be a readable buffer of at least \p hashlen Bytes.
  * \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 up to the hash length,
@@ -935,13 +929,11 @@
  *                 if \p f_rng doesn't need a context argument.
  * \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.
- *                 This is only used if \p md_alg is #MBEDTLS_MD_NONE.
+ * \param hashlen  The length of the message digest or raw data in Bytes.
+ *                 If \p md_alg is not #MBEDTLS_MD_NONE, this must match the
+ *                 output length of the corresponding hash algorithm.
  * \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.
+ *                 This must be a readable buffer of at least \p hashlen Bytes.
  * \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
@@ -972,13 +964,11 @@
  * \param ctx      The initialized RSA public key context to use.
  * \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.
- *                 This is only used if \p md_alg is #MBEDTLS_MD_NONE.
+ * \param hashlen  The length of the message digest or raw data in Bytes.
+ *                 If \p md_alg is not #MBEDTLS_MD_NONE, this must match the
+ *                 output length of the corresponding hash algorithm.
  * \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.
+ *                 This must be a readable buffer of at least \p hashlen Bytes.
  * \param sig      The buffer holding the signature. This must be a readable
  *                 buffer of length \c ctx->len Bytes. For example, \c 256 Bytes
  *                 for an 2048-bit RSA modulus.
@@ -999,13 +989,11 @@
  * \param ctx      The initialized RSA public key context to use.
  * \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.
- *                 This is only used if \p md_alg is #MBEDTLS_MD_NONE.
+ * \param hashlen  The length of the message digest or raw data in Bytes.
+ *                 If \p md_alg is not #MBEDTLS_MD_NONE, this must match the
+ *                 output length of the corresponding hash algorithm.
  * \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.
+ *                 This must be a readable buffer of at least \p hashlen Bytes.
  * \param sig      The buffer holding the signature. This must be a readable
  *                 buffer of length \c ctx->len Bytes. For example, \c 256 Bytes
  *                 for an 2048-bit RSA modulus.
@@ -1036,13 +1024,11 @@
  * \param ctx      The initialized RSA public key context to use.
  * \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.
- *                 This is only used if \p md_alg is #MBEDTLS_MD_NONE.
+ * \param hashlen  The length of the message digest or raw data in Bytes.
+ *                 If \p md_alg is not #MBEDTLS_MD_NONE, this must match the
+ *                 output length of the corresponding hash algorithm.
  * \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.
+ *                 This must be a readable buffer of at least \p hashlen Bytes.
  * \param sig      The buffer holding the signature. This must be a readable
  *                 buffer of length \c ctx->len Bytes. For example, \c 256 Bytes
  *                 for an 2048-bit RSA modulus.
@@ -1069,13 +1055,11 @@
  * \param ctx      The initialized RSA public key context to use.
  * \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.
- *                 This is only used if \p md_alg is #MBEDTLS_MD_NONE.
+ * \param hashlen  The length of the message digest or raw data in Bytes.
+ *                 If \p md_alg is not #MBEDTLS_MD_NONE, this must match the
+ *                 output length of the corresponding hash algorithm.
  * \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.
+ *                 This must be a readable buffer of at least \p hashlen Bytes.
  * \param mgf1_hash_id      The message digest algorithm used for the
  *                          verification operation and the mask generation
  *                          function (MGF1). For more details on the encoding
diff --git a/library/rsa.c b/library/rsa.c
index d4e63b6..ed1632a 100644
--- a/library/rsa.c
+++ b/library/rsa.c
@@ -1790,7 +1790,8 @@
         if( md_info == NULL )
             return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA );
 
-        hashlen = mbedtls_md_get_size( md_info );
+        if( hashlen != mbedtls_md_get_size( md_info ) )
+            return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA );
     }
 
     md_info = mbedtls_md_info_from_type( (mbedtls_md_type_t) ctx->hash_id );
@@ -1925,14 +1926,13 @@
  * Parameters:
  * - md_alg:  Identifies the hash algorithm used to generate the given hash;
  *            MBEDTLS_MD_NONE if raw data is signed.
- * - hashlen: Length of hash in case hashlen is MBEDTLS_MD_NONE.
+ * - hashlen: Length of hash. Must match md_alg if that's not NONE.
  * - hash:    Buffer containing the hashed message or the raw data.
  * - dst_len: Length of the encoded message.
  * - dst:     Buffer to hold the encoded message.
  *
  * Assumptions:
- * - hash has size hashlen if md_alg == MBEDTLS_MD_NONE.
- * - hash has size corresponding to md_alg if md_alg != MBEDTLS_MD_NONE.
+ * - hash has size hashlen.
  * - dst points to a buffer of size at least dst_len.
  *
  */
@@ -1957,7 +1957,8 @@
         if( mbedtls_oid_get_oid_by_md( md_alg, &oid, &oid_size ) != 0 )
             return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA );
 
-        hashlen = mbedtls_md_get_size( md_info );
+        if( hashlen != mbedtls_md_get_size( md_info ) )
+            return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA );
 
         /* Double-check that 8 + hashlen + oid_size can be used as a
          * 1-byte ASN.1 length encoding and that there's no overflow. */
@@ -2022,6 +2023,8 @@
      *                                 TAG-NULL + LEN [ NULL ] ]
      *                 TAG-OCTET + LEN [ HASH ] ]
      */
+    if( 0x08 + oid_size + hashlen >= 0x80 )
+        return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA );
     *p++ = MBEDTLS_ASN1_SEQUENCE | MBEDTLS_ASN1_CONSTRUCTED;
     *p++ = (unsigned char)( 0x08 + oid_size + hashlen );
     *p++ = MBEDTLS_ASN1_SEQUENCE | MBEDTLS_ASN1_CONSTRUCTED;
@@ -2203,7 +2206,8 @@
         if( md_info == NULL )
             return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA );
 
-        hashlen = mbedtls_md_get_size( md_info );
+        if( hashlen != mbedtls_md_get_size( md_info ) )
+            return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA );
     }
 
     md_info = mbedtls_md_info_from_type( mgf1_hash_id );
@@ -2674,7 +2678,7 @@
     }
 
     if( mbedtls_rsa_pkcs1_sign( &rsa, myrand, NULL,
-                                MBEDTLS_MD_SHA1, 0,
+                                MBEDTLS_MD_SHA1, 20,
                                 sha1sum, rsa_ciphertext ) != 0 )
     {
         if( verbose != 0 )
@@ -2687,7 +2691,7 @@
     if( verbose != 0 )
         mbedtls_printf( "passed\n  PKCS#1 sig. verify: " );
 
-    if( mbedtls_rsa_pkcs1_verify( &rsa, MBEDTLS_MD_SHA1, 0,
+    if( mbedtls_rsa_pkcs1_verify( &rsa, MBEDTLS_MD_SHA1, 20,
                                   sha1sum, rsa_ciphertext ) != 0 )
     {
         if( verbose != 0 )
diff --git a/programs/pkey/dh_client.c b/programs/pkey/dh_client.c
index dbdee2d..28bfb89 100644
--- a/programs/pkey/dh_client.c
+++ b/programs/pkey/dh_client.c
@@ -221,7 +221,7 @@
     }
 
     if( ( ret = mbedtls_rsa_pkcs1_verify( &rsa, MBEDTLS_MD_SHA256,
-                                          0, hash, p ) ) != 0 )
+                                          32, hash, p ) ) != 0 )
     {
         mbedtls_printf( " failed\n  ! mbedtls_rsa_pkcs1_verify returned %d\n\n", ret );
         goto exit;
diff --git a/programs/pkey/dh_server.c b/programs/pkey/dh_server.c
index 0d5be4e..79c313c 100644
--- a/programs/pkey/dh_server.c
+++ b/programs/pkey/dh_server.c
@@ -229,7 +229,7 @@
     buf[n + 1] = (unsigned char)( rsa.MBEDTLS_PRIVATE(len)      );
 
     if( ( ret = mbedtls_rsa_pkcs1_sign( &rsa, NULL, NULL, MBEDTLS_MD_SHA256,
-                                0, hash, buf + n + 2 ) ) != 0 )
+                                32, hash, buf + n + 2 ) ) != 0 )
     {
         mbedtls_printf( " failed\n  ! mbedtls_rsa_pkcs1_sign returned %d\n\n", ret );
         goto exit;
diff --git a/programs/pkey/rsa_sign.c b/programs/pkey/rsa_sign.c
index d9ba3bb..ebc88e4 100644
--- a/programs/pkey/rsa_sign.c
+++ b/programs/pkey/rsa_sign.c
@@ -147,7 +147,7 @@
     }
 
     if( ( ret = mbedtls_rsa_pkcs1_sign( &rsa, NULL, NULL, MBEDTLS_MD_SHA256,
-                                20, hash, buf ) ) != 0 )
+                                32, hash, buf ) ) != 0 )
     {
         mbedtls_printf( " failed\n  ! mbedtls_rsa_pkcs1_sign returned -0x%0x\n\n", (unsigned int) -ret );
         goto exit;
diff --git a/programs/pkey/rsa_verify.c b/programs/pkey/rsa_verify.c
index fff568a..5a68246 100644
--- a/programs/pkey/rsa_verify.c
+++ b/programs/pkey/rsa_verify.c
@@ -141,7 +141,7 @@
     }
 
     if( ( ret = mbedtls_rsa_pkcs1_verify( &rsa, MBEDTLS_MD_SHA256,
-                                          20, hash, buf ) ) != 0 )
+                                          32, hash, buf ) ) != 0 )
     {
         mbedtls_printf( " failed\n  ! mbedtls_rsa_pkcs1_verify returned -0x%0x\n\n", (unsigned int) -ret );
         goto exit;
diff --git a/tests/suites/test_suite_pk.function b/tests/suites/test_suite_pk.function
index 0d4ff08..6e93bc6 100644
--- a/tests/suites/test_suite_pk.function
+++ b/tests/suites/test_suite_pk.function
@@ -452,9 +452,10 @@
 
     if( digest != MBEDTLS_MD_NONE )
     {
-        TEST_ASSERT( mbedtls_md( mbedtls_md_info_from_type( digest ),
-                     message_str->x, message_str->len, hash_result ) == 0 );
-        hash_len = 0;
+        const mbedtls_md_info_t *md_info = mbedtls_md_info_from_type( digest );
+        TEST_ASSERT( mbedtls_md( md_info, message_str->x, message_str->len,
+                                 hash_result ) == 0 );
+        hash_len = mbedtls_md_get_size( md_info );
     }
     else
     {
@@ -619,7 +620,8 @@
 {
     mbedtls_pk_context pk;
     size_t sig_len;
-    unsigned char hash[MBEDTLS_MD_MAX_SIZE];
+    unsigned char hash[32]; // Hard-coded for SHA256
+    size_t hash_len = sizeof( hash );
     unsigned char sig[MBEDTLS_PK_SIGNATURE_MAX_SIZE];
     void *rs_ctx = NULL;
 #if defined(MBEDTLS_ECDSA_C) && defined(MBEDTLS_ECP_RESTARTABLE)
@@ -643,7 +645,7 @@
     TEST_ASSERT( pk_genkey( &pk, parameter ) == 0 );
 
     TEST_ASSERT( mbedtls_pk_sign_restartable( &pk, MBEDTLS_MD_SHA256,
-                 hash, sizeof hash, sig, &sig_len,
+                 hash, hash_len, sig, &sig_len,
                  mbedtls_test_rnd_std_rand, NULL, rs_ctx ) == sign_ret );
     if( sign_ret == 0 )
         TEST_ASSERT( sig_len <= MBEDTLS_PK_SIGNATURE_MAX_SIZE );
@@ -651,22 +653,22 @@
         sig_len = MBEDTLS_PK_SIGNATURE_MAX_SIZE;
 
     TEST_ASSERT( mbedtls_pk_verify( &pk, MBEDTLS_MD_SHA256,
-                            hash, sizeof hash, sig, sig_len ) == verify_ret );
+                            hash, hash_len, sig, sig_len ) == verify_ret );
 
     if( verify_ret == 0 )
     {
         hash[0]++;
         TEST_ASSERT( mbedtls_pk_verify( &pk, MBEDTLS_MD_SHA256,
-                                hash, sizeof hash, sig, sig_len ) != 0 );
+                                hash, hash_len, sig, sig_len ) != 0 );
         hash[0]--;
 
         sig[0]++;
         TEST_ASSERT( mbedtls_pk_verify( &pk, MBEDTLS_MD_SHA256,
-                                hash, sizeof hash, sig, sig_len ) != 0 );
+                                hash, hash_len, sig, sig_len ) != 0 );
         sig[0]--;
     }
 
-    TEST_ASSERT( mbedtls_pk_sign( &pk, MBEDTLS_MD_SHA256, hash, sizeof hash,
+    TEST_ASSERT( mbedtls_pk_sign( &pk, MBEDTLS_MD_SHA256, hash, hash_len,
                                   sig, &sig_len,
                                   mbedtls_test_rnd_std_rand,
                                   NULL ) == sign_ret );
@@ -676,7 +678,7 @@
         sig_len = MBEDTLS_PK_SIGNATURE_MAX_SIZE;
 
     TEST_ASSERT( mbedtls_pk_verify_restartable( &pk, MBEDTLS_MD_SHA256,
-                 hash, sizeof hash, sig, sig_len, rs_ctx ) == verify_ret );
+                 hash, hash_len, sig, sig_len, rs_ctx ) == verify_ret );
 
     if( verify_ret == 0 )
     {
diff --git a/tests/suites/test_suite_pkcs1_v15.function b/tests/suites/test_suite_pkcs1_v15.function
index 2089c62..6f859d5 100644
--- a/tests/suites/test_suite_pkcs1_v15.function
+++ b/tests/suites/test_suite_pkcs1_v15.function
@@ -269,6 +269,7 @@
                             data_t * result_str, int result )
 {
     unsigned char hash_result[MBEDTLS_MD_MAX_SIZE];
+    const mbedtls_md_info_t *md_info = mbedtls_md_info_from_type( digest );
     unsigned char output[128];
     mbedtls_rsa_context ctx;
     mbedtls_mpi N, P, Q, E;
@@ -298,13 +299,13 @@
     TEST_ASSERT( mbedtls_rsa_complete( &ctx ) == 0 );
     TEST_ASSERT( mbedtls_rsa_check_privkey( &ctx ) == 0 );
 
+    if( md_info != NULL )
+        TEST_ASSERT( mbedtls_md( md_info, message_str->x, message_str->len, hash_result ) == 0 );
 
-    if( mbedtls_md_info_from_type( digest ) != NULL )
-        TEST_ASSERT( mbedtls_md( mbedtls_md_info_from_type( digest ), message_str->x, message_str->len, hash_result ) == 0 );
-
-    TEST_ASSERT( mbedtls_rsa_pkcs1_sign( &ctx, &mbedtls_test_rnd_buffer_rand,
-                                         &info, digest, 0, hash_result,
-                                         output ) == result );
+    TEST_ASSERT( mbedtls_rsa_pkcs1_sign(
+                     &ctx, &mbedtls_test_rnd_buffer_rand, &info,
+                     digest, mbedtls_md_get_size( md_info ), hash_result,
+                     output ) == result );
     if( result == 0 )
     {
 
@@ -326,6 +327,7 @@
                               data_t * result_str, int result )
 {
     unsigned char hash_result[MBEDTLS_MD_MAX_SIZE];
+    const mbedtls_md_info_t *md_info = mbedtls_md_info_from_type( digest );
     mbedtls_rsa_context ctx;
     mbedtls_mpi N, E;
     ((void) salt);
@@ -343,10 +345,10 @@
     TEST_ASSERT( mbedtls_rsa_check_pubkey( &ctx ) == 0 );
 
 
-    if( mbedtls_md_info_from_type( digest ) != NULL )
-        TEST_ASSERT( mbedtls_md( mbedtls_md_info_from_type( digest ), message_str->x, message_str->len, hash_result ) == 0 );
+    if( md_info != NULL )
+        TEST_ASSERT( mbedtls_md( md_info, message_str->x, message_str->len, hash_result ) == 0 );
 
-    TEST_ASSERT( mbedtls_rsa_pkcs1_verify( &ctx, digest, 0, hash_result, result_str->x ) == result );
+    TEST_ASSERT( mbedtls_rsa_pkcs1_verify( &ctx, digest, mbedtls_md_get_size( md_info ), hash_result, result_str->x ) == result );
 
 exit:
     mbedtls_mpi_free( &N ); mbedtls_mpi_free( &E );
diff --git a/tests/suites/test_suite_pkcs1_v21.function b/tests/suites/test_suite_pkcs1_v21.function
index ec5591f..27b0990 100644
--- a/tests/suites/test_suite_pkcs1_v21.function
+++ b/tests/suites/test_suite_pkcs1_v21.function
@@ -123,6 +123,7 @@
                             int result )
 {
     unsigned char hash_result[MBEDTLS_MD_MAX_SIZE];
+    const mbedtls_md_info_t *md_info = mbedtls_md_info_from_type( digest );
     unsigned char output[512];
     mbedtls_rsa_context ctx;
     mbedtls_test_rnd_buf_info info;
@@ -152,14 +153,15 @@
     TEST_ASSERT( mbedtls_rsa_complete( &ctx ) == 0 );
     TEST_ASSERT( mbedtls_rsa_check_privkey( &ctx ) == 0 );
 
-    if( mbedtls_md_info_from_type( digest ) != NULL )
-        TEST_ASSERT( mbedtls_md( mbedtls_md_info_from_type( digest ), message_str->x, message_str->len, hash_result ) == 0 );
+    if( md_info != NULL )
+        TEST_ASSERT( mbedtls_md( md_info, message_str->x, message_str->len, hash_result ) == 0 );
 
     if (fixed_salt_length == MBEDTLS_RSA_SALT_LEN_ANY)
     {
-        TEST_ASSERT( mbedtls_rsa_pkcs1_sign( &ctx, &mbedtls_test_rnd_buffer_rand,
-                                             &info, digest, 0,hash_result,
-                                             output ) == result );
+        TEST_ASSERT( mbedtls_rsa_pkcs1_sign(
+                         &ctx, &mbedtls_test_rnd_buffer_rand, &info,
+                         digest, mbedtls_md_get_size( md_info ), hash_result,
+                         output ) == result );
         if( result == 0 )
         {
             ASSERT_COMPARE( output, ctx.len, result_str->x, result_str->len );
@@ -169,9 +171,10 @@
         info.length = rnd_buf->len;
     }
 
-    TEST_ASSERT( mbedtls_rsa_rsassa_pss_sign_ext( &ctx, &mbedtls_test_rnd_buffer_rand,
-                                                  &info, digest, 0, hash_result,
-                                                  fixed_salt_length, output ) == result );
+    TEST_ASSERT( mbedtls_rsa_rsassa_pss_sign_ext(
+                     &ctx, &mbedtls_test_rnd_buffer_rand, &info,
+                     digest, mbedtls_md_get_size( md_info ), hash_result,
+                     fixed_salt_length, output ) == result );
     if( result == 0 )
     {
         ASSERT_COMPARE( output, ctx.len, result_str->x, result_str->len );
@@ -190,6 +193,7 @@
                               char * salt, data_t * result_str, int result )
 {
     unsigned char hash_result[MBEDTLS_MD_MAX_SIZE];
+    const mbedtls_md_info_t *md_info = mbedtls_md_info_from_type( digest );
     mbedtls_rsa_context ctx;
     mbedtls_mpi N, E;
     ((void) salt);
@@ -208,10 +212,10 @@
     TEST_ASSERT( mbedtls_rsa_check_pubkey( &ctx ) == 0 );
 
 
-    if( mbedtls_md_info_from_type( digest ) != NULL )
-        TEST_ASSERT( mbedtls_md( mbedtls_md_info_from_type( digest ), message_str->x, message_str->len, hash_result ) == 0 );
+    if( md_info != NULL )
+        TEST_ASSERT( mbedtls_md( md_info, message_str->x, message_str->len, hash_result ) == 0 );
 
-    TEST_ASSERT( mbedtls_rsa_pkcs1_verify( &ctx, digest, 0, hash_result, result_str->x ) == result );
+    TEST_ASSERT( mbedtls_rsa_pkcs1_verify( &ctx, digest, mbedtls_md_get_size( md_info ), hash_result, result_str->x ) == result );
 
 exit:
     mbedtls_mpi_free( &N ); mbedtls_mpi_free( &E );
@@ -248,9 +252,12 @@
 
     if( msg_digest_id != MBEDTLS_MD_NONE )
     {
-        TEST_ASSERT( mbedtls_md( mbedtls_md_info_from_type( msg_digest_id ),
-                     message_str->x, message_str->len, hash_result ) == 0 );
-        hash_len = 0;
+        const mbedtls_md_info_t *md_info =
+            mbedtls_md_info_from_type( msg_digest_id );
+        TEST_ASSERT( mbedtls_md( md_info,
+                                 message_str->x, message_str->len,
+                                 hash_result ) == 0 );
+        hash_len = mbedtls_md_get_size( md_info );
     }
     else
     {
diff --git a/tests/suites/test_suite_rsa.function b/tests/suites/test_suite_rsa.function
index db30fc4..f5f4aac 100644
--- a/tests/suites/test_suite_rsa.function
+++ b/tests/suites/test_suite_rsa.function
@@ -84,6 +84,7 @@
                              data_t * result_str, int result )
 {
     unsigned char hash_result[MBEDTLS_MD_MAX_SIZE];
+    const mbedtls_md_info_t *md_info = mbedtls_md_info_from_type( digest );
     unsigned char output[256];
     mbedtls_rsa_context ctx;
     mbedtls_mpi N, P, Q, E;
@@ -109,13 +110,13 @@
     TEST_ASSERT( mbedtls_rsa_complete( &ctx ) == 0 );
     TEST_ASSERT( mbedtls_rsa_check_privkey( &ctx ) == 0 );
 
+    if( md_info != NULL )
+        TEST_ASSERT( mbedtls_md( md_info, message_str->x, message_str->len, hash_result ) == 0 );
 
-    if( mbedtls_md_info_from_type( digest ) != NULL )
-        TEST_ASSERT( mbedtls_md( mbedtls_md_info_from_type( digest ), message_str->x, message_str->len, hash_result ) == 0 );
-
-    TEST_ASSERT( mbedtls_rsa_pkcs1_sign( &ctx, &mbedtls_test_rnd_pseudo_rand,
-                                         &rnd_info, digest, 0, hash_result,
-                                         output ) == result );
+    TEST_ASSERT( mbedtls_rsa_pkcs1_sign(
+                     &ctx, &mbedtls_test_rnd_pseudo_rand, &rnd_info,
+                     digest, mbedtls_md_get_size( md_info ), hash_result,
+                     output ) == result );
     if( result == 0 )
     {
 
@@ -137,8 +138,8 @@
                                data_t * result_str, int result )
 {
     unsigned char hash_result[MBEDTLS_MD_MAX_SIZE];
+    const mbedtls_md_info_t *md_info = mbedtls_md_info_from_type( digest );
     mbedtls_rsa_context ctx;
-
     mbedtls_mpi N, E;
 
     mbedtls_mpi_init( &N ); mbedtls_mpi_init( &E );
@@ -153,11 +154,10 @@
     TEST_ASSERT( mbedtls_rsa_get_len( &ctx ) == (size_t) ( mod / 8 ) );
     TEST_ASSERT( mbedtls_rsa_check_pubkey( &ctx ) == 0 );
 
+    if( md_info != NULL )
+        TEST_ASSERT( mbedtls_md( md_info, message_str->x, message_str->len, hash_result ) == 0 );
 
-    if( mbedtls_md_info_from_type( digest ) != NULL )
-        TEST_ASSERT( mbedtls_md( mbedtls_md_info_from_type( digest ), message_str->x, message_str->len, hash_result ) == 0 );
-
-    TEST_ASSERT( mbedtls_rsa_pkcs1_verify( &ctx, digest, 0, hash_result, result_str->x ) == result );
+    TEST_ASSERT( mbedtls_rsa_pkcs1_verify( &ctx, digest, mbedtls_md_get_size( md_info ), hash_result, result_str->x ) == result );
 
 exit:
     mbedtls_mpi_free( &N ); mbedtls_mpi_free( &E );