br_gcm_context Struct Reference

Context structure for GCM. More...

Data Fields
const br_aead_class *	vtable
	Pointer to vtable for this context. More...

Detailed Description

Context structure for GCM.

GCM is an AEAD mode that combines a block cipher in CTR mode with a MAC based on GHASH, to provide authenticated encryption:

• Any block cipher with 16-byte blocks can be used with GCM.
• The nonce can have any length, from 0 up to 2^64-1 bits; however, 96-bit nonces (12 bytes) are recommended (nonces with a length distinct from 12 bytes are internally hashed, which risks reusing nonce value with a small but not always negligible probability).
• Additional authenticated data may have length up to 2^64-1 bits.
• Message length may range up to 2^39-256 bits at most.
• The authentication tag has length 16 bytes.

The GCM initialisation function receives as parameter an initialised block cipher implementation context, with the secret key already set. A pointer to that context will be kept within the GCM context structure. It is up to the caller to allocate and initialise that block cipher context.

Field Documentation

vtable

const br_aead_class* br_gcm_context::vtable

Pointer to vtable for this context.

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The documentation for this struct was generated from the following file:

• bearssl_aead.h