• Registered: 2021-05-11
  • Posts: 1

Topic: wc_AesGcmEncrypt/Decrypt nonce/iv size

What are the effective limits of the IV size for these calls?
We intend to use a 128bit (16 byte) IV, will all of the bits be used?

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  • Registered: 2015-10-07
  • Posts: 430

Re: wc_AesGcmEncrypt/Decrypt nonce/iv size

Hi miennaco,

The AES GCM IV is normally 12-bytes, but it supports any length. An IV size not equal to 12-byte will first be GHASH'd then used.

See the code here:
https://github.com/wolfSSL/wolfssl/blob … es.c#L7180

Thanks,
David Garske, wolfSSL

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