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Meta-repository for Miscreant: misuse-resistant symmetric encryption library with AES-SIV (RFC 5297) and AES-PMAC-SIV support
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Best practices for key reuse? #195

Closed assafmo closed 4 years ago

assafmo commented 4 years ago

What's the best practice for reusing an encryption key? After how many messages/GiBs it's recommended to rotate the encryption key?

tarcieri commented 4 years ago

RFC 5297 Section 6.1 lists P_MAX (maximum size of a plaintext message) at 2^132 octets.

That doesn't seem like a good data volume limit for AES-CMAC-SIV or AES-PMAC-SIV, however. At the very least, their data volumes shouldn't exceed the birthday bound of AES, which is 2^64 AES blocks, or approximately 295 exabytes.