docs(s3): add intro

Author: SamyOubouaziz

storage/object/reference-content/supported-checksums.mdx

@@ -13,6 +13,8 @@ categories:
   - network
 ---
 
+Checksums are critical components in ensuring data integrity within object storage systems. They are calculated values, typically a hash or a cyclic redundancy check (CRC), obtained from the content of an object. By comparing the stored checksum with one recalculated during data retrieval, storage systems can detect and often correct errors caused by corruption, transmission issues, or hardware failures.
+
 Scaleway Object Storage supports several checksum algorithms that allow you to verify the integrity of your objects:
 
 - **CRC32**: a non-cryptographic checksum that generates a 32-bit hash value used to detect errors in data transmission, by applying a specific cyclic redundancy check (CRC) algorithm.
@@ -22,7 +24,4 @@ Scaleway Object Storage supports several checksum algorithms that allow you to v
 - **SHA-1**: a cryptographic Secure Hash Algorithm (SHA) that generates a 160-bit (20-byte) hash value from input data.
 
 - **SHA-256**: a cryptographic Secure Hash Algorithm that generates a 256-bit unique hash value, preferred for modern security protocols due to SHA-1 vulnerabilities.
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