CKM_AES_GCM

GCM is the Galois/Counter Mode of operation of the AES algorithm for symmetric key encryption.

Usage Notes

Data size

The maximum allowed data size for this mechanism is 64KB (64 * 1024).

Initialization Vector (IV)

Random initialization vector (IV) is supported and recommended for GCM and for GMAC. In FIPS mode, the HSM firmware does not accept the IV parameter, and instead returns a generated IV.

The internal IV is a randomly generated 16-byte IV.

JCPROV

AES-GMAC and AES-GCM are supported in JCPROV. Use CK_AES_CMAC_PARAMS.java to define the GMAC operation. Implementation is the same as for PKCS#11.

Accumulating data

Our GMAC and GCM are single part operations, so even if they are called using multi-part API, we accumulate the data (up to a maximum) and return data only on the “final” operation. That is the meaning of "Accumulating" in the table, below.

Summary

FIPS approved?	Yes
Supported functions	Encrypt | Decrypt
Minimum key length (bits)	128
Minimum key length for FIPS use (bits)	N/A
Minimum legacy key length for FIPS use (bits)	128
Maximum key length (bits)	256
Block size	16
Digest size	0
Key types	AES
Algorithms	AES
Modes	GCM
Flags	Extractable | Accumulating