An optional parameter to set the Customer-Supplied Encryption key for rewrite source object.
Application developers can generate their own encryption keys to protect the data in GCS. This is known as a Customer-Supplied Encryption key (CSEK). If the application provides a CSEK, GCS does not retain the key. The object data, the object CRC32 checksum, and its MD5 hash (if applicable) are all encrypted with this key, and the key is required to read any of these elements back.
Care must be taken to save and protect these keys, if lost, the data is not recoverable. Also, applications should avoid generating predictable keys, as this weakens the encryption.
This option is used only in rewrite operations and it defines the key used for the source object.
[[["Easy to understand","easyToUnderstand","thumb-up"],["Solved my problem","solvedMyProblem","thumb-up"],["Other","otherUp","thumb-up"]],[["Missing the information I need","missingTheInformationINeed","thumb-down"],["Too complicated / too many steps","tooComplicatedTooManySteps","thumb-down"],["Out of date","outOfDate","thumb-down"],["Samples / code issue","samplesCodeIssue","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2025-08-14 UTC."],[[["\u003cp\u003eThis document outlines the \u003ccode\u003eSourceEncryptionKey\u003c/code\u003e structure for Google Cloud Storage (GCS) C++ library versions, ranging from 2.11.0 to the latest release candidate 2.37.0-rc.\u003c/p\u003e\n"],["\u003cp\u003e\u003ccode\u003eSourceEncryptionKey\u003c/code\u003e is an optional parameter to set a Customer-Supplied Encryption Key (CSEK) for source objects during rewrite operations in GCS, and this key is not retained by GCS.\u003c/p\u003e\n"],["\u003cp\u003eThe \u003ccode\u003eFromBinaryKey\u003c/code\u003e function creates a \u003ccode\u003eSourceEncryptionKey\u003c/code\u003e parameter from a binary key, requiring the key to be exactly 32 bytes long.\u003c/p\u003e\n"],["\u003cp\u003eThe \u003ccode\u003eFromBase64Key\u003c/code\u003e function creates a \u003ccode\u003eSourceEncryptionKey\u003c/code\u003e from a base64-encoded key, which must decode to exactly 32 bytes.\u003c/p\u003e\n"],["\u003cp\u003eThe static \u003ccode\u003eprefix()\u003c/code\u003e function is available within the \u003ccode\u003eSourceEncryptionKey\u003c/code\u003e structure, but its specific functionality is not described in the content.\u003c/p\u003e\n"]]],[],null,[]]
