[edk2-devel] [PATCH v1 5/7] MdePkg/AesLib: Definition for AES library class interface

[PierreGondois]

From: Pierre Gondois <Pierre.Gondois at arm.com>

BZ: https://bugzilla.tianocore.org/show_bug.cgi?id=3970

The FIPS PUB 197: "Advanced Encryption Standard (AES)"
details the AES algorithm. Add a library to allow
different architecture specific implementations.

Signed-off-by: Pierre Gondois <pierre.gondois at arm.com>
---
 MdePkg/Include/Library/AesLib.h | 104 ++++++++++++++++++++++++++++++++
 MdePkg/MdePkg.dec               |   4 ++
 2 files changed, 108 insertions(+)
 create mode 100644 MdePkg/Include/Library/AesLib.h

diff --git a/MdePkg/Include/Library/AesLib.h b/MdePkg/Include/Library/AesLib.h
new file mode 100644
index 000000000000..bc3408bb249b
--- /dev/null
+++ b/MdePkg/Include/Library/AesLib.h
@@ -0,0 +1,104 @@
+/** @file
+  AES library.
+
+  Copyright (c) 2022, Arm Limited. All rights reserved.<BR>
+
+  SPDX-License-Identifier: BSD-2-Clause-Patent
+
+  @par Reference(s):
+   - FIPS 197 November 26, 2001:
+     Specification for the ADVANCED ENCRYPTION STANDARD (AES)
+**/
+
+#ifndef AES_LIB_H_
+#define AES_LIB_H_
+
+/// Key size in bytes.
+#define AES_KEY_SIZE_128  16
+#define AES_KEY_SIZE_192  24
+#define AES_KEY_SIZE_256  32
+#define AES_BLOCK_SIZE    16
+
+/*
+   The Key Expansion generates a total of Nb (Nr + 1) words with:
+    - Nb = 4:
+      Number of columns (32-bit words) comprising the State
+    - Nr = 10, 12, or 14:
+      Number of rounds.
+ */
+#define AES_MAX_KEYLENGTH_U32  (4 * (14 + 1))
+
+/** A context holding information to for AES encryption/decryption.
+ */
+typedef struct {
+  /// Expanded encryption key.
+  UINT32    ExpEncKey[AES_MAX_KEYLENGTH_U32];
+  /// Expanded decryption key.
+  UINT32    ExpDecKey[AES_MAX_KEYLENGTH_U32];
+  /// Key size, in bytes.
+  /// Must be one of 16|24|32.
+  UINT32    KeySize;
+} AES_CTX;
+
+/** Encrypt an AES block.
+
+  Buffers are little-endian. Overlapping is not checked.
+
+  @param [in]  AesCtx    AES context.
+                         AesCtx is initialized with AesInitCtx ().
+  @param [in]  InBlock   Input Block. The block to cipher.
+  @param [out] OutBlock  Output Block. The ciphered block.
+
+  @retval RETURN_SUCCESS            Success.
+  @retval RETURN_INVALID_PARAMETER  Invalid parameter.
+  @retval RETURN_UNSUPPORTED        Unsupported.
+**/
+RETURN_STATUS
+EFIAPI
+AesEncrypt (
+  IN  AES_CTX      *AesCtx,
+  IN  UINT8 CONST  *InBlock,
+  OUT UINT8        *OutBlock
+  );
+
+/** Decrypt an AES block.
+
+  Buffers are little-endian. Overlapping is not checked.
+
+  @param [in]  AesCtx    AES context.
+                         AesCtx is initialized with AesInitCtx ().
+  @param [in]  InBlock   Input Block. The block to de-cipher.
+  @param [out] OutBlock  Output Block. The de-ciphered block.
+
+  @retval RETURN_SUCCESS            Success.
+  @retval RETURN_INVALID_PARAMETER  Invalid parameter.
+  @retval RETURN_UNSUPPORTED        Unsupported.
+**/
+RETURN_STATUS
+EFIAPI
+AesDecrypt (
+  IN  AES_CTX      *AesCtx,
+  IN  UINT8 CONST  *InBlock,
+  OUT UINT8        *OutBlock
+  );
+
+/** Initialize an AES_CTX structure.
+
+  @param [in]       Key       AES key. Buffer of KeySize bytes.
+                              The buffer is little endian.
+  @param [in]       KeySize   Size of the key. Must be one of 128|192|256.
+  @param [in, out]  AesCtx    AES context to initialize.
+
+  @retval RETURN_SUCCESS            Success.
+  @retval RETURN_INVALID_PARAMETER  Invalid parameter.
+  @retval RETURN_UNSUPPORTED        Unsupported.
+**/
+RETURN_STATUS
+EFIAPI
+AesInitCtx (
+  IN      UINT8    *Key,
+  IN      UINT32   KeySize,
+  IN OUT  AES_CTX  *AesCtx
+  );
+
+#endif // AES_LIB_H_
diff --git a/MdePkg/MdePkg.dec b/MdePkg/MdePkg.dec
index 7ff26e22f915..078ae9323ba6 100644
--- a/MdePkg/MdePkg.dec
+++ b/MdePkg/MdePkg.dec
@@ -280,6 +280,10 @@ [LibraryClasses]
   #
   TrngLib|Include/Library/TrngLib.h
 
+  ##  @libraryclass  Provides AES encryption/decryption services.
+  #
+  AesLib|Include/Library/AesLib.h
+
 [LibraryClasses.IA32, LibraryClasses.X64, LibraryClasses.AARCH64]
   ##  @libraryclass  Provides services to generate random number.
   #
-- 
2.25.1



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