Revert "Remove deprecated things from hashing modules"

This reverts commit c75d9f589bf392177dbeba7704693e53fe55cb19.

This was merged by mistake in development instead of development_3.0.

Signed-off-by: Manuel Pégourié-Gonnard <manuel.pegourie-gonnard@arm.com>
diff --git a/include/mbedtls/md4.h b/include/mbedtls/md4.h
index f9e3987..eeb1670 100644
--- a/include/mbedtls/md4.h
+++ b/include/mbedtls/md4.h
@@ -36,6 +36,9 @@
 #include <stddef.h>
 #include <stdint.h>
 
+/* MBEDTLS_ERR_MD4_HW_ACCEL_FAILED is deprecated and should not be used. */
+#define MBEDTLS_ERR_MD4_HW_ACCEL_FAILED                   -0x002D  /**< MD4 hardware accelerator failed */
+
 #ifdef __cplusplus
 extern "C" {
 #endif
@@ -165,6 +168,79 @@
 int mbedtls_internal_md4_process( mbedtls_md4_context *ctx,
                                   const unsigned char data[64] );
 
+#if !defined(MBEDTLS_DEPRECATED_REMOVED)
+#if defined(MBEDTLS_DEPRECATED_WARNING)
+#define MBEDTLS_DEPRECATED      __attribute__((deprecated))
+#else
+#define MBEDTLS_DEPRECATED
+#endif
+/**
+ * \brief          MD4 context setup
+ *
+ * \deprecated     Superseded by mbedtls_md4_starts_ret() in 2.7.0
+ *
+ * \param ctx      context to be initialized
+ *
+ * \warning        MD4 is considered a weak message digest and its use
+ *                 constitutes a security risk. We recommend considering
+ *                 stronger message digests instead.
+ *
+ */
+MBEDTLS_DEPRECATED void mbedtls_md4_starts( mbedtls_md4_context *ctx );
+
+/**
+ * \brief          MD4 process buffer
+ *
+ * \deprecated     Superseded by mbedtls_md4_update_ret() in 2.7.0
+ *
+ * \param ctx      MD4 context
+ * \param input    buffer holding the data
+ * \param ilen     length of the input data
+ *
+ * \warning        MD4 is considered a weak message digest and its use
+ *                 constitutes a security risk. We recommend considering
+ *                 stronger message digests instead.
+ *
+ */
+MBEDTLS_DEPRECATED void mbedtls_md4_update( mbedtls_md4_context *ctx,
+                                            const unsigned char *input,
+                                            size_t ilen );
+
+/**
+ * \brief          MD4 final digest
+ *
+ * \deprecated     Superseded by mbedtls_md4_finish_ret() in 2.7.0
+ *
+ * \param ctx      MD4 context
+ * \param output   MD4 checksum result
+ *
+ * \warning        MD4 is considered a weak message digest and its use
+ *                 constitutes a security risk. We recommend considering
+ *                 stronger message digests instead.
+ *
+ */
+MBEDTLS_DEPRECATED void mbedtls_md4_finish( mbedtls_md4_context *ctx,
+                                            unsigned char output[16] );
+
+/**
+ * \brief          MD4 process data block (internal use only)
+ *
+ * \deprecated     Superseded by mbedtls_internal_md4_process() in 2.7.0
+ *
+ * \param ctx      MD4 context
+ * \param data     buffer holding one block of data
+ *
+ * \warning        MD4 is considered a weak message digest and its use
+ *                 constitutes a security risk. We recommend considering
+ *                 stronger message digests instead.
+ *
+ */
+MBEDTLS_DEPRECATED void mbedtls_md4_process( mbedtls_md4_context *ctx,
+                                             const unsigned char data[64] );
+
+#undef MBEDTLS_DEPRECATED
+#endif /* !MBEDTLS_DEPRECATED_REMOVED */
+
 /**
  * \brief          Output = MD4( input buffer )
  *
@@ -183,6 +259,33 @@
                      size_t ilen,
                      unsigned char output[16] );
 
+#if !defined(MBEDTLS_DEPRECATED_REMOVED)
+#if defined(MBEDTLS_DEPRECATED_WARNING)
+#define MBEDTLS_DEPRECATED      __attribute__((deprecated))
+#else
+#define MBEDTLS_DEPRECATED
+#endif
+/**
+ * \brief          Output = MD4( input buffer )
+ *
+ * \deprecated     Superseded by mbedtls_md4_ret() in 2.7.0
+ *
+ * \param input    buffer holding the data
+ * \param ilen     length of the input data
+ * \param output   MD4 checksum result
+ *
+ * \warning        MD4 is considered a weak message digest and its use
+ *                 constitutes a security risk. We recommend considering
+ *                 stronger message digests instead.
+ *
+ */
+MBEDTLS_DEPRECATED void mbedtls_md4( const unsigned char *input,
+                                     size_t ilen,
+                                     unsigned char output[16] );
+
+#undef MBEDTLS_DEPRECATED
+#endif /* !MBEDTLS_DEPRECATED_REMOVED */
+
 #if defined(MBEDTLS_SELF_TEST)
 
 /**