Corrected parameter of mbedtls_aes_crypt_ecb in _decryptBuffer() of Updater.cpp

[victorfleischauer]

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Description of Change

Changed the parameter MBEDTLS_AES_ENCRYPT to MBEDTLS_AES_DECRYPT for the function mbedtls_aes_crypt_ecb in the method _decryptBuffer(). This change can affect anyone who currently uses the decryption functionality of the Update.h library.

I hope this helps, or that my understanding is corrected, thanks!

Tests scenarios

As described in my Issue:

• Board: ESP32-S3-DevKitC-1 v1.0
• Version: 3.0.4
• IDE: PlatformIO
• Operating System: Windows 11

Description

A slightly modified version of the example sketch "OTAWebUpdater" to include

const uint8_t key[32] = {/* PUT YOUR KEY HERE */};
Update.setupCrypt(key, 0, 0, U_AES_DECRYPT_ON);

Related links

• Issue opened, will be closed by this PR
• Corrected branch name from previous pull request

[github-actions]

	Messages
📖	🎉 Good Job! All checks are passing!

👋 Hello victorfleischauer, we appreciate your contribution to this project!

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[github-actions]

Memory usage test (comparing PR against master branch)

The table below shows the summary of memory usage change (decrease - increase) in bytes and percentage for each target.

Memory	FLASH [bytes]		FLASH [%]		RAM [bytes]		RAM [%]
Target	DEC	INC	DEC	INC	DEC	INC	DEC	INC
ESP32S3	0	0	0.00	0.00	0	0	0.00	0.00
ESP32S2	0	0	0.00	0.00	0	0	0.00	0.00
ESP32C3	0	0	0.00	0.00	0	0	0.00	0.00
ESP32C6	0	0	0.00	0.00	0	0	0.00	0.00
ESP32H2	0	0	0.00	0.00	0	0	0.00	0.00
ESP32	0	0	0.00	0.00	0	0	0.00	0.00

Click to expand the detailed deltas report [usage change in BYTES]

Target	ESP32S3		ESP32S2		ESP32C3		ESP32C6		ESP32H2		ESP32
Example	FLASH	RAM	FLASH	RAM	FLASH	RAM	FLASH	RAM	FLASH	RAM	FLASH	RAM
Update/examples/AWS_S3_OTA_Update	0	0	0	0	0	0	0	0	-	-	0	0
Update/examples/HTTPS_OTA_Update	0	0	0	0	0	0	0	0	-	-	0	0
Update/examples/HTTP_Client_AES_OTA_Update	0	0	0	0	0	0	0	0	-	-	0	0
Update/examples/HTTP_Server_AES_OTA_Update	0	0	0	0	0	0	0	0	-	-	0	0
Update/examples/OTAWebUpdater	0	0	0	0	0	0	0	0	-	-	0	0
Update/examples/SD_Update	0	0	0	0	0	0	0	0	0	0	0	0

[github-actions]

Test Results

 56 files   -  83   56 suites   - 83   5m 14s ⏱️ - 1h 6m 30s
 21 tests  -  12   21 ✅  -   1  0 💤 ±0  0 ❌ ±0 
135 runs   - 142  135 ✅  - 115  0 💤 ±0  0 ❌ ±0 

Results for commit b200c42. ± Comparison against base commit 66c9c0b.

This pull request removes 12 tests.

performance.coremark.test_coremark ‑ test_coremark
performance.fibonacci.test_fibonacci ‑ test_fibonacci
performance.psramspeed.test_psramspeed ‑ test_psramspeed
performance.ramspeed.test_ramspeed ‑ test_ramspeed
performance.superpi.test_superpi ‑ test_superpi
test_touch_errors
test_touch_interrtupt
test_touch_read
validation.periman.test_periman ‑ test_periman
validation.timer.test_timer ‑ test_timer
…

[lucasssvaz]

AES algorithm is used inverted in flash encryption, so the flash encryption "encrypt" operation is AES decrypt and the "decrypt" operation is AES encrypt. This is for performance reasons and does not alter the effeciency of the algorithm.

This is intended. You can read more about it here:
https://docs.espressif.com/projects/esp-idf/en/release-v5.1/esp32/security/flash-encryption.html#flash-encryption-algorithm

[victorfleischauer]

AES algorithm is used inverted in flash encryption, so the flash encryption "encrypt" operation is AES decrypt and the "decrypt" operation is AES encrypt. This is for performance reasons and does not alter the effeciency of the algorithm.

This is intended. You can read more about it here:
https://docs.espressif.com/projects/esp-idf/en/release-v5.1/esp32/security/flash-encryption.html#flash-encryption-algorithm

Thank you for correcting me! I will close the PR and Issue and try to correct my project later