diff --git a/tests/suites/test_suite_pk.data b/tests/suites/test_suite_pk.data
index cfb4281..bf1bcc7 100644
--- a/tests/suites/test_suite_pk.data
+++ b/tests/suites/test_suite_pk.data
@@ -153,3 +153,16 @@
 RSA hash_len overflow (size_t vs unsigned int)
 depends_on:MBEDTLS_RSA_C:MBEDTLS_HAVE_INT64
 pk_rsa_overflow:
+
+PK opaque mock
+pk_opaque_mock:
+
+PK opaque with failed allocation
+pk_opaque_fail_allocation:
+
+PK opaque minimal
+pk_opaque_minimal:
+
+PK opaque wrapper (RSA)
+depends_on:MBEDTLS_RSA_C
+pk_opaque_wrapper:
diff --git a/tests/suites/test_suite_pk.function b/tests/suites/test_suite_pk.function
index b8b222b..f73022c 100644
--- a/tests/suites/test_suite_pk.function
+++ b/tests/suites/test_suite_pk.function
@@ -1,5 +1,8 @@
 /* BEGIN_HEADER */
+#include <string.h>
+
 #include "mbedtls/pk.h"
+#include "mbedtls/pk_info.h"
 
 /* For error codes */
 #include "mbedtls/ecp.h"
@@ -39,14 +42,15 @@
 }
 
 #if defined(MBEDTLS_RSA_C)
-int mbedtls_rsa_decrypt_func( void *ctx, int mode, size_t *olen,
+
+static int mbedtls_rsa_decrypt_func( void *ctx, int mode, size_t *olen,
                        const unsigned char *input, unsigned char *output,
                        size_t output_max_len )
 {
     return( mbedtls_rsa_pkcs1_decrypt( (mbedtls_rsa_context *) ctx, NULL, NULL, mode, olen,
                                input, output, output_max_len ) );
 }
-int mbedtls_rsa_sign_func( void *ctx,
+static int mbedtls_rsa_sign_func( void *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, unsigned char *sig )
@@ -54,11 +58,269 @@
     return( mbedtls_rsa_pkcs1_sign( (mbedtls_rsa_context *) ctx, f_rng, p_rng, mode,
                             md_alg, hashlen, hash, sig ) );
 }
-size_t mbedtls_rsa_key_len_func( void *ctx )
+static size_t mbedtls_rsa_key_len_func( void *ctx )
 {
     return( ((const mbedtls_rsa_context *) ctx)->len );
 }
+
+/* Prepare a raw RSA context with a small random key. */
+static void pk_rsa_prepare( mbedtls_rsa_context *raw )
+{
+    mbedtls_rsa_init( raw, MBEDTLS_RSA_PKCS_V15, MBEDTLS_MD_NONE );
+    mbedtls_rsa_gen_key( raw, rnd_std_rand, NULL, RSA_KEY_SIZE, 3 );
+}
+
+/* Test the RSA context tested_ctx by comparing its operation with a
+   generic RSA context which is initialized with the key in raw. */
+static void pk_rsa_match( mbedtls_rsa_context *raw,
+                          mbedtls_pk_context *tested_ctx,
+                          int sign_ret, int verify_ret,
+                          int encrypt_ret, int decrypt_ret,
+                          int debug_ret )
+{
+    mbedtls_pk_context basic_ctx;
+    mbedtls_pk_debug_item dbg_items[10];
+    unsigned char hash[50], sig[1000];
+    unsigned char msg[50], ciph[1000], test[1000];
+    size_t sig_len, ciph_len, test_len;
+
+    memset( hash, 0x2a, sizeof hash );
+    memset( sig, 0, sizeof sig );
+    memset( msg, 0x2a, sizeof msg );
+    memset( ciph, 0, sizeof ciph );
+    memset( test, 0, sizeof test );
+
+    /* Initiliaze basic PK RSA context with raw key */
+    mbedtls_pk_init( &basic_ctx );
+    TEST_ASSERT( mbedtls_pk_setup( &basic_ctx,
+                                   mbedtls_pk_info_from_type( MBEDTLS_PK_RSA ) ) == 0 );
+    TEST_ASSERT( mbedtls_rsa_copy( mbedtls_pk_rsa( basic_ctx ), raw ) == 0 );
+
+    /* Test administrative functions */
+    TEST_ASSERT( mbedtls_pk_can_do( tested_ctx, MBEDTLS_PK_RSA ) );
+    TEST_ASSERT( mbedtls_pk_get_bitlen( tested_ctx ) == RSA_KEY_SIZE );
+    TEST_ASSERT( mbedtls_pk_get_len( tested_ctx ) == RSA_KEY_LEN );
+    TEST_ASSERT( mbedtls_pk_signature_size( tested_ctx ) == RSA_KEY_LEN );
+
+    /* Test signature */
+    TEST_ASSERT( mbedtls_pk_sign( tested_ctx, MBEDTLS_MD_NONE, hash, sizeof hash,
+                          sig, &sig_len, rnd_std_rand, NULL ) == sign_ret );
+    if( sign_ret == 0 )
+    {
+#if defined(MBEDTLS_HAVE_INT64)
+        TEST_ASSERT( mbedtls_pk_sign( tested_ctx, MBEDTLS_MD_NONE, hash, (size_t)-1,
+                                      NULL, NULL, rnd_std_rand, NULL ) ==
+                     MBEDTLS_ERR_PK_BAD_INPUT_DATA );
+#endif /* MBEDTLS_HAVE_INT64 */
+        TEST_ASSERT( sig_len == RSA_KEY_LEN );
+        TEST_ASSERT( mbedtls_pk_verify( &basic_ctx, MBEDTLS_MD_NONE,
+                                        hash, sizeof hash, sig, sig_len ) == 0 );
+    }
+
+    /* Test verification */
+    TEST_ASSERT( mbedtls_pk_sign( &basic_ctx, MBEDTLS_MD_NONE, hash, sizeof hash,
+                          sig, &sig_len, rnd_std_rand, NULL ) == 0 );
+    TEST_ASSERT( mbedtls_pk_verify( tested_ctx, MBEDTLS_MD_NONE,
+                            hash, sizeof hash, sig, sig_len ) == verify_ret );
+    if( verify_ret == 0 )
+    {
+        TEST_ASSERT( mbedtls_pk_verify( tested_ctx, MBEDTLS_MD_NONE,
+                                        hash, sizeof hash, sig, sig_len - 1 ) == MBEDTLS_ERR_RSA_VERIFY_FAILED );
+        sig[sig_len-1] ^= 1;
+        TEST_ASSERT( mbedtls_pk_verify( tested_ctx, MBEDTLS_MD_NONE,
+                                        hash, sizeof hash, sig, sig_len ) == MBEDTLS_ERR_RSA_INVALID_PADDING );
+    }
+
+    /* Test encryption */
+    TEST_ASSERT( mbedtls_pk_encrypt( tested_ctx, msg, sizeof msg,
+                             ciph, &ciph_len, sizeof ciph,
+                             rnd_std_rand, NULL ) == encrypt_ret );
+    if( encrypt_ret == 0 )
+    {
+        TEST_ASSERT( mbedtls_pk_decrypt( &basic_ctx, ciph, ciph_len,
+                                         test, &test_len, sizeof test,
+                                         rnd_std_rand, NULL ) == 0 );
+        TEST_ASSERT( test_len == sizeof msg );
+        TEST_ASSERT( memcmp( test, msg, test_len ) == 0 );
+    }
+
+    /* Test decryption */
+    TEST_ASSERT( mbedtls_pk_encrypt( &basic_ctx, msg, sizeof msg,
+                             ciph, &ciph_len, sizeof ciph,
+                             rnd_std_rand, NULL ) == 0 );
+    TEST_ASSERT( mbedtls_pk_decrypt( tested_ctx, ciph, ciph_len,
+                             test, &test_len, sizeof test,
+                             rnd_std_rand, NULL ) == decrypt_ret );
+    if( decrypt_ret == 0 )
+    {
+        TEST_ASSERT( test_len == sizeof msg );
+        TEST_ASSERT( memcmp( test, msg, test_len ) == 0 );
+    }
+
+    /* Test debug */
+    TEST_ASSERT( mbedtls_pk_debug( tested_ctx, dbg_items ) == debug_ret );
+
+exit:
+    mbedtls_pk_free( &basic_ctx );
+}
+
+#define OPAQUE_MOCK_CAN_DO MBEDTLS_PK_RSA
+#define OPAQUE_MOCK_BITLEN 'b'
+#define OPAQUE_MOCK_MD_ALG MBEDTLS_MD_SHA256
+#define OPAQUE_MOCK_SIGNATURE_SIZE 4
+#define OPAQUE_MOCK_GOOD_SIGNATURE "good"
+static const unsigned char opaque_mock_hash[8] = "HASHhash";
+static const unsigned char opaque_mock_reference_input[10] = "INPUTinput";
+static const unsigned char opaque_mock_input[10] = "INPUTinput";
+static const unsigned char opaque_mock_reference_encrypted[12] = "C:JOQVUjoqvu";
+static const unsigned char opaque_mock_reference_decrypted[12] = "P:HMOTShmots";
+static char opaque_mock_fake_ctx = 'c';
+static mbedtls_pk_debug_item opaque_mock_pk_debug_item;
+static int opaque_mock_debug_called_correctly = 0;
+static int opaque_mock_free_called_correctly = 0;
+
+static size_t opaque_mock_get_bitlen( const void *ctx )
+{
+    TEST_ASSERT( ctx == &opaque_mock_fake_ctx );
+    return( OPAQUE_MOCK_BITLEN );
+exit:
+    return( INT_MIN );
+}
+
+static int opaque_mock_can_do( const void *ctx,
+                               mbedtls_pk_type_t type )
+{
+    TEST_ASSERT( ctx == &opaque_mock_fake_ctx );
+    return( type == OPAQUE_MOCK_CAN_DO );
+exit:
+    return( INT_MIN );
+}
+
+static int opaque_mock_verify_func( void *ctx, mbedtls_md_type_t md_alg,
+                                    const unsigned char *hash, size_t hash_len,
+                                    const unsigned char *sig, size_t sig_len )
+{
+    TEST_ASSERT( ctx == &opaque_mock_fake_ctx );
+    TEST_ASSERT( md_alg == OPAQUE_MOCK_MD_ALG );
+    TEST_ASSERT( hash_len == sizeof( opaque_mock_hash ) );
+    TEST_ASSERT( hash == opaque_mock_hash );
+    if( sig_len != OPAQUE_MOCK_SIGNATURE_SIZE )
+        return( MBEDTLS_ERR_PK_SIG_LEN_MISMATCH );
+    if( memcmp( sig, OPAQUE_MOCK_GOOD_SIGNATURE, OPAQUE_MOCK_SIGNATURE_SIZE ) )
+        return( MBEDTLS_ERR_PK_INVALID_SIGNATURE );
+    return( 0 );
+exit:
+    return( INT_MIN );
+}
+
+static int opaque_mock_sign_func( void *ctx, mbedtls_md_type_t md_alg,
+                                  const unsigned char *hash, size_t hash_len,
+                                  unsigned char *sig, size_t *sig_len,
+                                  int (*f_rng)(void *, unsigned char *, size_t),
+                                  void *p_rng )
+{
+    TEST_ASSERT( ctx == &opaque_mock_fake_ctx );
+    TEST_ASSERT( md_alg == OPAQUE_MOCK_MD_ALG );
+    TEST_ASSERT( hash_len == sizeof( opaque_mock_hash ) );
+    TEST_ASSERT( hash == opaque_mock_hash );
+    memcpy( sig, OPAQUE_MOCK_GOOD_SIGNATURE, OPAQUE_MOCK_SIGNATURE_SIZE );
+    *sig_len = OPAQUE_MOCK_SIGNATURE_SIZE;
+    (void) f_rng;
+    (void) p_rng;
+    return( 0 );
+exit:
+    return( INT_MIN );
+}
+
+static int opaque_mock_decrypt_func( void *ctx, const unsigned char *input, size_t ilen,
+                                     unsigned char *output, size_t *olen, size_t osize,
+                                     int (*f_rng)(void *, unsigned char *, size_t),
+                                     void *p_rng )
+{
+    TEST_ASSERT( ctx == &opaque_mock_fake_ctx );
+    TEST_ASSERT( ilen == sizeof( opaque_mock_reference_input ) );
+    TEST_ASSERT( !memcmp( input, opaque_mock_reference_input,
+                          sizeof( opaque_mock_reference_input ) ) );
+    if( osize < sizeof( opaque_mock_reference_decrypted ) )
+        return( MBEDTLS_ERR_PK_BUFFER_TOO_SMALL );
+    *olen = sizeof( opaque_mock_reference_decrypted );
+    memcpy( output, opaque_mock_reference_decrypted, sizeof( opaque_mock_reference_decrypted ) );
+    (void) f_rng;
+    (void) p_rng;
+    return( 0 );
+exit:
+    return( INT_MIN );
+}
+
+static int opaque_mock_encrypt_func( void *ctx, const unsigned char *input, size_t ilen,
+                                     unsigned char *output, size_t *olen, size_t osize,
+                                     int (*f_rng)(void *, unsigned char *, size_t),
+                                     void *p_rng )
+{
+    TEST_ASSERT( ctx == &opaque_mock_fake_ctx );
+    TEST_ASSERT( ilen == sizeof( opaque_mock_reference_input ) );
+    TEST_ASSERT( !memcmp( input, opaque_mock_reference_input,
+                          sizeof( opaque_mock_reference_input ) ) );
+    if( osize < sizeof( opaque_mock_reference_encrypted ) )
+        return( MBEDTLS_ERR_PK_BUFFER_TOO_SMALL );
+    *olen = sizeof( opaque_mock_reference_encrypted );
+    memcpy( output, opaque_mock_reference_encrypted, sizeof( opaque_mock_reference_encrypted ) );
+    (void) f_rng;
+    (void) p_rng;
+    return( 0 );
+exit:
+    return( INT_MIN );
+}
+
+static int opaque_mock_check_pair_func( const mbedtls_pk_context *pub,
+                                        const void *prv )
+{
+    TEST_ASSERT( prv == &opaque_mock_fake_ctx );
+    if( mbedtls_pk_get_type( pub ) != MBEDTLS_PK_RSA )
+        return( MBEDTLS_ERR_PK_TYPE_MISMATCH );
+    return( 0 );
+exit:
+    return( INT_MIN );
+}
+
+static void *opaque_mock_ctx_alloc_func( void )
+{
+    return( &opaque_mock_fake_ctx );
+}
+static void *opaque_mock_ctx_alloc_fail( void )
+{
+    return( NULL );
+}
+
+static void opaque_mock_ctx_free_func( void *ctx )
+{
+    TEST_ASSERT( ctx == &opaque_mock_fake_ctx );
+    opaque_mock_free_called_correctly = 1;
+exit:
+    return;
+}
+
+static void opaque_mock_debug_func( const void *ctx,
+                                   mbedtls_pk_debug_item *items )
+{
+    TEST_ASSERT( ctx == &opaque_mock_fake_ctx );
+    TEST_ASSERT( items == &opaque_mock_pk_debug_item );
+    opaque_mock_debug_called_correctly = 1;
+exit:
+    return;
+}
+
+static size_t opaque_mock_signature_size_func( const void *ctx )
+{
+    TEST_ASSERT( ctx == &opaque_mock_fake_ctx );
+    return( OPAQUE_MOCK_SIGNATURE_SIZE );
+exit:
+    return( -1 );
+}
+
+
 #endif /* MBEDTLS_RSA_C */
+
 /* END_HEADER */
 
 /* BEGIN_DEPENDENCIES
@@ -451,74 +713,292 @@
      * Test it against the public operations (encrypt, verify) of a
      * corresponding rsa context.
      */
+    mbedtls_pk_context alt;
     mbedtls_rsa_context raw;
-    mbedtls_pk_context rsa, alt;
-    mbedtls_pk_debug_item dbg_items[10];
-    unsigned char hash[50], sig[1000];
-    unsigned char msg[50], ciph[1000], test[1000];
-    size_t sig_len, ciph_len, test_len;
-    int ret = MBEDTLS_ERR_PK_TYPE_MISMATCH;
 
-    mbedtls_rsa_init( &raw, MBEDTLS_RSA_PKCS_V15, MBEDTLS_MD_NONE );
-    mbedtls_pk_init( &rsa ); mbedtls_pk_init( &alt );
+    /* Generate an RSA key to use in both contexts */
+    pk_rsa_prepare( &raw );
 
-    memset( hash, 0x2a, sizeof hash );
-    memset( sig, 0, sizeof sig );
-    memset( msg, 0x2a, sizeof msg );
-    memset( ciph, 0, sizeof ciph );
-    memset( test, 0, sizeof test );
-
-    /* Initiliaze PK RSA context with random key */
-    TEST_ASSERT( mbedtls_pk_setup( &rsa,
-                              mbedtls_pk_info_from_type( MBEDTLS_PK_RSA ) ) == 0 );
-    TEST_ASSERT( pk_genkey( &rsa ) == 0 );
-
-    /* Extract key to the raw rsa context */
-    TEST_ASSERT( mbedtls_rsa_copy( &raw, mbedtls_pk_rsa( rsa ) ) == 0 );
-
-    /* Initialize PK RSA_ALT context */
+    /* Set up the alt context with the generated key */
+    mbedtls_pk_init( &alt );
     TEST_ASSERT( mbedtls_pk_setup_rsa_alt( &alt, (void *) &raw,
-                 mbedtls_rsa_decrypt_func, mbedtls_rsa_sign_func, mbedtls_rsa_key_len_func ) == 0 );
+                                           mbedtls_rsa_decrypt_func,
+                                           mbedtls_rsa_sign_func,
+                                           mbedtls_rsa_key_len_func ) == 0 );
 
-    /* Test administrative functions */
-    TEST_ASSERT( mbedtls_pk_can_do( &alt, MBEDTLS_PK_RSA ) );
-    TEST_ASSERT( mbedtls_pk_get_bitlen( &alt ) == RSA_KEY_SIZE );
-    TEST_ASSERT( mbedtls_pk_get_len( &alt ) == RSA_KEY_LEN );
+    /* Check the metadata in the alt context */
     TEST_ASSERT( mbedtls_pk_get_type( &alt ) == MBEDTLS_PK_RSA_ALT );
     TEST_ASSERT( strcmp( mbedtls_pk_get_name( &alt ), "RSA-alt" ) == 0 );
 
-    /* Test signature */
-    TEST_ASSERT( mbedtls_pk_sign( &alt, MBEDTLS_MD_NONE, hash, sizeof hash,
-                          sig, &sig_len, rnd_std_rand, NULL ) == 0 );
-#if defined(MBEDTLS_HAVE_INT64)
-    TEST_ASSERT( mbedtls_pk_sign( &alt, MBEDTLS_MD_NONE, hash, (size_t)-1,
-                          NULL, NULL, rnd_std_rand, NULL ) ==
-                 MBEDTLS_ERR_PK_BAD_INPUT_DATA );
-#endif /* MBEDTLS_HAVE_INT64 */
-    TEST_ASSERT( sig_len == RSA_KEY_LEN );
-    TEST_ASSERT( mbedtls_pk_verify( &rsa, MBEDTLS_MD_NONE,
-                            hash, sizeof hash, sig, sig_len ) == 0 );
-
-    /* Test decrypt */
-    TEST_ASSERT( mbedtls_pk_encrypt( &rsa, msg, sizeof msg,
-                             ciph, &ciph_len, sizeof ciph,
-                             rnd_std_rand, NULL ) == 0 );
-    TEST_ASSERT( mbedtls_pk_decrypt( &alt, ciph, ciph_len,
-                             test, &test_len, sizeof test,
-                             rnd_std_rand, NULL ) == 0 );
-    TEST_ASSERT( test_len == sizeof msg );
-    TEST_ASSERT( memcmp( test, msg, test_len ) == 0 );
-
-    /* Test forbidden operations */
-    TEST_ASSERT( mbedtls_pk_encrypt( &alt, msg, sizeof msg,
-                             ciph, &ciph_len, sizeof ciph,
-                             rnd_std_rand, NULL ) == ret );
-    TEST_ASSERT( mbedtls_pk_verify( &alt, MBEDTLS_MD_NONE,
-                            hash, sizeof hash, sig, sig_len ) == ret );
-    TEST_ASSERT( mbedtls_pk_debug( &alt, dbg_items ) == ret );
+    /* Exercise the alt context */
+    pk_rsa_match( &raw, &alt,
+                  0, MBEDTLS_ERR_PK_TYPE_MISMATCH,
+                  MBEDTLS_ERR_PK_TYPE_MISMATCH, 0,
+                  MBEDTLS_ERR_PK_TYPE_MISMATCH );
 
 exit:
     mbedtls_rsa_free( &raw );
-    mbedtls_pk_free( &rsa ); mbedtls_pk_free( &alt );
+    mbedtls_pk_free( &alt );
+}
+/* END_CASE */
+
+/* BEGIN_CASE */
+void pk_opaque_mock( )
+{
+    mbedtls_pk_info_t info =
+    {
+        MBEDTLS_PK_OPAQUE,
+        "mock",
+        opaque_mock_get_bitlen,
+        opaque_mock_can_do,
+        opaque_mock_verify_func,
+        opaque_mock_sign_func,
+        opaque_mock_decrypt_func,
+        opaque_mock_encrypt_func,
+        opaque_mock_check_pair_func,
+        opaque_mock_ctx_alloc_func,
+        opaque_mock_ctx_free_func,
+        opaque_mock_debug_func,
+        opaque_mock_signature_size_func,
+    };
+    mbedtls_pk_context ctx;
+    unsigned char sig[OPAQUE_MOCK_SIGNATURE_SIZE] = OPAQUE_MOCK_GOOD_SIGNATURE;
+    unsigned char input[sizeof( opaque_mock_reference_input )];
+    unsigned char output[sizeof( opaque_mock_reference_decrypted )] = "garbage";
+    size_t len;
+
+    mbedtls_pk_init( &ctx );
+    TEST_ASSERT( mbedtls_pk_setup( &ctx, &info ) == 0 );
+
+    TEST_ASSERT( mbedtls_pk_get_type( &ctx ) == MBEDTLS_PK_OPAQUE );
+    TEST_ASSERT( mbedtls_pk_get_name( &ctx ) == info.name );
+    TEST_ASSERT( mbedtls_pk_get_bitlen( &ctx ) == OPAQUE_MOCK_BITLEN );
+    TEST_ASSERT( mbedtls_pk_can_do( &ctx, OPAQUE_MOCK_CAN_DO ) == 1 );
+    TEST_ASSERT( mbedtls_pk_can_do( &ctx, OPAQUE_MOCK_CAN_DO ^ 1 ) == 0 );
+    TEST_ASSERT( mbedtls_pk_signature_size( &ctx ) == OPAQUE_MOCK_SIGNATURE_SIZE );
+
+    TEST_ASSERT( mbedtls_pk_verify( &ctx, OPAQUE_MOCK_MD_ALG,
+                                    opaque_mock_hash, sizeof( opaque_mock_hash ),
+                                    sig, OPAQUE_MOCK_SIGNATURE_SIZE ) == 0 );
+    TEST_ASSERT( mbedtls_pk_verify( &ctx, OPAQUE_MOCK_MD_ALG,
+                                    opaque_mock_hash, sizeof( opaque_mock_hash ),
+                                    sig, OPAQUE_MOCK_SIGNATURE_SIZE - 1 ) ==
+                 MBEDTLS_ERR_PK_SIG_LEN_MISMATCH );
+    sig[0] ^= 1;
+    TEST_ASSERT( mbedtls_pk_verify( &ctx, OPAQUE_MOCK_MD_ALG,
+                                    opaque_mock_hash, sizeof( opaque_mock_hash ),
+                                    sig, OPAQUE_MOCK_SIGNATURE_SIZE ) ==
+                 MBEDTLS_ERR_PK_INVALID_SIGNATURE );
+    len = -42;
+    TEST_ASSERT( mbedtls_pk_sign( &ctx, OPAQUE_MOCK_MD_ALG,
+                                  opaque_mock_hash, sizeof( opaque_mock_hash ),
+                                  sig, &len, NULL, NULL ) == 0 );
+    TEST_ASSERT( len == OPAQUE_MOCK_SIGNATURE_SIZE );
+
+    memcpy( input, opaque_mock_reference_input,
+            sizeof( opaque_mock_reference_input ) );
+    len = -42;
+    TEST_ASSERT( mbedtls_pk_encrypt( &ctx, input, sizeof( input ),
+                                     output, &len,
+                                     sizeof( opaque_mock_reference_encrypted ),
+                                     NULL, NULL ) == 0);
+    TEST_ASSERT( memcmp( input, opaque_mock_reference_input,
+                         sizeof( opaque_mock_reference_input ) ) == 0 );
+    TEST_ASSERT( len == sizeof( opaque_mock_reference_encrypted ) );
+    TEST_ASSERT( memcmp( output, opaque_mock_reference_encrypted,
+                         sizeof( opaque_mock_reference_encrypted ) ) == 0 );
+    len = -42;
+    TEST_ASSERT( mbedtls_pk_decrypt( &ctx, input, sizeof( input ),
+                                     output, &len,
+                                     sizeof( opaque_mock_reference_decrypted ),
+                                     NULL, NULL ) == 0);
+    TEST_ASSERT( memcmp( input, opaque_mock_reference_input,
+                         sizeof( opaque_mock_reference_input ) ) == 0 );
+    TEST_ASSERT( len == sizeof( opaque_mock_reference_decrypted ) );
+    TEST_ASSERT( memcmp( output, opaque_mock_reference_decrypted,
+                         sizeof( opaque_mock_reference_decrypted ) ) == 0 );
+
+    TEST_ASSERT( mbedtls_pk_check_pair( NULL, &ctx ) ==
+                 MBEDTLS_ERR_PK_BAD_INPUT_DATA );
+    TEST_ASSERT( mbedtls_pk_check_pair( &ctx, &ctx ) == 0 );
+    {
+        mbedtls_pk_context pub;
+        mbedtls_pk_init( &pub );
+        TEST_ASSERT( mbedtls_pk_check_pair( &pub, &ctx ) ==
+                     MBEDTLS_ERR_PK_BAD_INPUT_DATA );
+
+        TEST_ASSERT( mbedtls_pk_setup( &pub,
+                     mbedtls_pk_info_from_type( MBEDTLS_PK_RSA ) ) == 0 );
+        TEST_ASSERT( mbedtls_pk_check_pair( &pub, &ctx ) == 0 );
+        mbedtls_pk_free( &pub );
+
+        TEST_ASSERT( mbedtls_pk_setup( &pub,
+                     mbedtls_pk_info_from_type( MBEDTLS_PK_ECDSA ) ) == 0 );
+        TEST_ASSERT( mbedtls_pk_check_pair( &pub, &ctx ) ==
+                     MBEDTLS_ERR_PK_TYPE_MISMATCH );
+        mbedtls_pk_free( &pub );
+}
+
+    opaque_mock_debug_called_correctly = 0;
+    TEST_ASSERT( mbedtls_pk_debug( &ctx, &opaque_mock_pk_debug_item ) == 0 );
+    TEST_ASSERT( opaque_mock_debug_called_correctly );
+
+    opaque_mock_free_called_correctly = 0;
+    mbedtls_pk_free( &ctx );
+    TEST_ASSERT( opaque_mock_free_called_correctly );
+    return;
+
+exit:
+    mbedtls_pk_free( &ctx );
+}
+/* END_CASE */
+
+/* BEGIN_CASE */
+void pk_opaque_minimal( )
+{
+    mbedtls_pk_info_t info =
+    {
+        MBEDTLS_PK_OPAQUE,
+        "mock",
+        opaque_mock_get_bitlen,
+        opaque_mock_can_do,
+        NULL,
+        NULL,
+        NULL,
+        NULL,
+        NULL,
+        NULL,
+        opaque_mock_ctx_free_func,
+        NULL,
+        NULL,
+    };
+    mbedtls_pk_context ctx;
+
+    mbedtls_pk_init( &ctx );
+    TEST_ASSERT( mbedtls_pk_setup( &ctx, &info ) == 0 );
+    ctx.pk_ctx = &opaque_mock_fake_ctx;
+
+    TEST_ASSERT( mbedtls_pk_get_type( &ctx ) == MBEDTLS_PK_OPAQUE );
+    TEST_ASSERT( mbedtls_pk_get_name( &ctx ) == info.name );
+    TEST_ASSERT( mbedtls_pk_get_bitlen( &ctx ) == OPAQUE_MOCK_BITLEN );
+    TEST_ASSERT( mbedtls_pk_can_do( &ctx, OPAQUE_MOCK_CAN_DO ) == 1 );
+    TEST_ASSERT( mbedtls_pk_can_do( &ctx, OPAQUE_MOCK_CAN_DO ^ 1 ) == 0 );
+    TEST_ASSERT( mbedtls_pk_signature_size( &ctx ) ==
+                 ( OPAQUE_MOCK_BITLEN + 7 ) / 8 );
+
+    TEST_ASSERT( mbedtls_pk_verify( &ctx, OPAQUE_MOCK_MD_ALG,
+                                    NULL, 0, NULL, 0 ) ==
+                 MBEDTLS_ERR_PK_TYPE_MISMATCH );
+    TEST_ASSERT( mbedtls_pk_sign( &ctx, OPAQUE_MOCK_MD_ALG, NULL, 0,
+                                  NULL, NULL, NULL, NULL ) ==
+                 MBEDTLS_ERR_PK_TYPE_MISMATCH );
+    TEST_ASSERT( mbedtls_pk_encrypt( &ctx, NULL, 0,
+                                     NULL, NULL, 0, NULL, NULL ) ==
+                 MBEDTLS_ERR_PK_TYPE_MISMATCH);
+    TEST_ASSERT( mbedtls_pk_decrypt( &ctx, NULL, 0,
+                                     NULL, NULL, 0, NULL, NULL ) ==
+                 MBEDTLS_ERR_PK_TYPE_MISMATCH);
+
+    TEST_ASSERT( mbedtls_pk_check_pair( NULL, &ctx ) ==
+                 MBEDTLS_ERR_PK_BAD_INPUT_DATA );
+    TEST_ASSERT( mbedtls_pk_check_pair( &ctx, &ctx ) == 0 );
+    {
+        mbedtls_pk_context pub;
+        mbedtls_pk_init( &pub );
+        TEST_ASSERT( mbedtls_pk_setup( &pub,
+                     mbedtls_pk_info_from_type( MBEDTLS_PK_RSA ) ) == 0 );
+        TEST_ASSERT( mbedtls_pk_check_pair( &pub, &ctx ) ==
+                     MBEDTLS_ERR_PK_FEATURE_UNAVAILABLE );
+        mbedtls_pk_free( &pub );
+}
+
+    TEST_ASSERT( mbedtls_pk_debug( &ctx, &opaque_mock_pk_debug_item ) ==
+                 MBEDTLS_ERR_PK_TYPE_MISMATCH );
+
+    opaque_mock_free_called_correctly = 0;
+    mbedtls_pk_free( &ctx );
+    TEST_ASSERT( opaque_mock_free_called_correctly );
+    return;
+
+exit:
+    mbedtls_pk_free( &ctx );
+}
+/* END_CASE */
+
+/* BEGIN_CASE */
+void pk_opaque_fail_allocation( )
+{
+    mbedtls_pk_info_t info =
+    {
+        MBEDTLS_PK_OPAQUE,
+        "mock",
+        NULL,
+        NULL,
+        NULL,
+        NULL,
+        NULL,
+        NULL,
+        NULL,
+        opaque_mock_ctx_alloc_fail,
+        NULL,
+        NULL,
+        NULL,
+    };
+    mbedtls_pk_context ctx;
+    mbedtls_pk_init( &ctx );
+    TEST_ASSERT( mbedtls_pk_setup( &ctx, &info ) ==
+                 MBEDTLS_ERR_PK_ALLOC_FAILED );
+    TEST_ASSERT( ctx.pk_info == NULL );
+    TEST_ASSERT( ctx.pk_ctx == NULL );
+exit:
+    mbedtls_pk_free( &ctx );
+}
+/* END_CASE */
+
+/* BEGIN_CASE depends_on:MBEDTLS_RSA_C:MBEDTLS_PK_RSA_ALT_SUPPORT */
+void pk_opaque_wrapper( )
+{
+    /* Test an opaque context that's a wrapper around the usual RSA
+       implementation against an independent raw RSA context. */
+    mbedtls_pk_context opaque;
+    mbedtls_rsa_context raw;
+    const mbedtls_pk_info_t *mbedtls_rsa_info =
+        mbedtls_pk_info_from_type( MBEDTLS_PK_RSA );
+    mbedtls_pk_info_t pk_rsa_opaque_info =
+    {
+        MBEDTLS_PK_OPAQUE,
+        "RSA-opaque-wrapper",
+        mbedtls_rsa_info->get_bitlen,
+        mbedtls_rsa_info->can_do,
+        mbedtls_rsa_info->verify_func,
+        mbedtls_rsa_info->sign_func,
+        mbedtls_rsa_info->decrypt_func,
+        mbedtls_rsa_info->encrypt_func,
+        NULL, // we don't test check_pair here
+        mbedtls_rsa_info->ctx_alloc_func,
+        mbedtls_rsa_info->ctx_free_func,
+        mbedtls_rsa_info->debug_func,
+        NULL, // signature_size_func: the fallback implementation is fine
+    };
+
+    /* Generate an RSA key to use in both contexts */
+    pk_rsa_prepare( &raw );
+
+    /* Set up the opaque context with the generated key */
+    mbedtls_pk_init( &opaque );
+    TEST_ASSERT( mbedtls_pk_setup( &opaque, &pk_rsa_opaque_info ) == 0 );
+    mbedtls_rsa_copy( opaque.pk_ctx, &raw );
+
+    /* Check the metadata in the opaque context */
+    TEST_ASSERT( mbedtls_pk_get_type( &opaque ) == MBEDTLS_PK_OPAQUE );
+    TEST_ASSERT( strcmp( mbedtls_pk_get_name( &opaque ),
+                         "RSA-opaque-wrapper" ) == 0 );
+
+    /* Exercise the opaque context */
+    pk_rsa_match( &raw, &opaque, 0, 0, 0, 0, 0 );
+
+exit:
+    mbedtls_rsa_free( &raw );
+    mbedtls_pk_free( &opaque );
 }
 /* END_CASE */