docs: update crypto API documentation with supported algorithms

Document all supported cryptographic algorithms and their variants in the NuttX Crypto API subsystem, including:
- AES-CBC with 128/192/256-bit key sizes
- HMAC and hash functions
- AES GMAC and CMAC
- ChaCha20-Poly1305
- And other supported algorithms

This documentation provides a comprehensive reference for developers using the cryptographic services.

Signed-off-by: makejian <makejian@xiaomi.com>

Documentation/components/crypto.rst

@@ -2,4 +2,136 @@
 Crypto API Subsystem
 ====================
 
-In the future this page will contain details about the Crypto API in NuttX.
+Overview
+========
+
+The NuttX Crypto API subsystem provides a unified interface for cryptographic operations, supporting various encryption, decryption, hashing, and authentication algorithms. The subsystem abstracts hardware and software crypto implementations through a common interface.
+
+Supported Algorithms
+====================
+
+Symmetric Encryption Algorithms
+--------------------------------
+
+**AES (Advanced Encryption Standard)**
+
+- AES-CBC Mode:
+  - CRYPTO_AES_CBC (128-bit key size)
+  - CRYPTO_AES_192_CBC (192-bit key size)
+  - CRYPTO_AES_256_CBC (256-bit key size)
+
+- AES-CTR Mode (Counter mode):
+  - CRYPTO_AES_CTR
+
+- AES-XTS Mode (XEX-based Tweaked CodeBook):
+  - CRYPTO_AES_XTS
+
+- AES-GCM Mode (Galois/Counter Mode):
+  - CRYPTO_AES_GCM_16
+
+- AES-OFB Mode (Output Feedback):
+  - CRYPTO_AES_OFB
+
+- AES-CFB Mode (Cipher Feedback):
+  - CRYPTO_AES_CFB_8 (8-bit)
+  - CRYPTO_AES_CFB_128 (128-bit)
+
+**Other Block Cipher Modes**
+
+- Blowfish (BLF):
+  - CRYPTO_BLF_CBC
+
+- CAST (CAST-128):
+  - CRYPTO_CAST_CBC
+
+- Rijndael (128-bit):
+  - CRYPTO_RIJNDAEL128_CBC
+
+- Null (No encryption):
+  - CRYPTO_NULL
+
+Authentication and Hashing Algorithms
+--------------------------------------
+
+**HMAC (Hash-based Message Authentication Code)**
+
+- MD5-HMAC:
+  - CRYPTO_MD5_HMAC
+
+- SHA-1 HMAC:
+  - CRYPTO_SHA1_HMAC
+
+- SHA-2 HMAC:
+  - CRYPTO_SHA2_256_HMAC (256-bit)
+  - CRYPTO_SHA2_384_HMAC (384-bit)
+  - CRYPTO_SHA2_512_HMAC (512-bit)
+
+**Hash Functions**
+
+- MD5:
+  - CRYPTO_MD5
+
+- SHA-1:
+  - CRYPTO_SHA1
+
+- SHA-2:
+  - CRYPTO_SHA2_224 (224-bit)
+  - CRYPTO_SHA2_256 (256-bit)
+  - CRYPTO_SHA2_384 (384-bit)
+  - CRYPTO_SHA2_512 (512-bit)
+
+- RIPEMD-160:
+  - CRYPTO_RIPEMD160 (as hash function)
+  - CRYPTO_RIPEMD160_HMAC
+
+**Message Authentication Codes**
+
+- AES-GMAC (Galois Message Authentication Code):
+  - CRYPTO_AES_128_GMAC (128-bit key)
+  - CRYPTO_AES_192_GMAC (192-bit key)
+  - CRYPTO_AES_256_GMAC (256-bit key)
+  - CRYPTO_AES_GMAC (generic)
+
+- AES-CMAC (Cipher-based Message Authentication Code):
+  - CRYPTO_AES_CMAC
+  - CRYPTO_AES_128_CMAC (128-bit)
+
+- Poly1305:
+  - CRYPTO_POLY1305
+  - CRYPTO_CHACHA20_POLY1305
+  - CRYPTO_CHACHA20_POLY1305_MAC
+
+**Stream Ciphers**
+
+- ChaCha20:
+  - CRYPTO_CHACHA20_POLY1305 (with Poly1305 MAC)
+
+Integrity and Checksums
+------------------------
+
+- CRC-32:
+  - CRYPTO_CRC32
+
+- Extended Sequence Numbers (ESN):
+  - CRYPTO_ESN
+
+Compression
+-----------
+
+- Deflate Compression:
+  - CRYPTO_DEFLATE_COMP
+
+Usage
+=====
+
+The Crypto API is accessed through the cryptodev interface, which provides ioctl commands for initializing cryptographic sessions and performing operations.
+
+Basic Usage Pattern
+-------------------
+
+1. Open the cryptodev device (/dev/crypto)
+2. Initialize a cryptographic session with desired algorithm
+3. Submit crypto operations (encrypt/decrypt/hash)
+4. Close the session when done
+
+For more details, refer to the cryptodev.h header file and specific driver documentation.