Variable AES_GCM_TAG_LENGTHSConst

Constant defining the AES-GCM tag length values in bits.

Remarks

NIST Special Publication 800-38D, Section 5.2.1.2 states that the tag length:

may be any one of the following five values: 128, 120, 112, 104, or 96

Although the NIST specification allows for tag lengths of 32 or 64 bits in certain applications, the use of shorter tag lengths can be problematic for GCM due to targeted forgery attacks. As a precaution, this implementation does not support tag lengths that are different from the five values defined by this constant. See Appendix C of the NIST SP 800-38D specification for additional guidance and details.

See

NIST SP 800-38D