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Does anyone know why the yubikey 4 supports RSA 4096, but ECC only goes up to 384 and not 521? Sure 384 is likely "enough" but ECC 521 is both faster and smalle
by georgyo 10y ago
Does anyone know why the yubikey 4 supports RSA 4096, but ECC only goes up to 384 and not 521? Sure 384 is likely "enough" but ECC 521 is both faster and smaller than RSA4096. I just can't seem to figure out why they would impose that limit.
- jwatte 10y agoProbably a hardware limitation?
- ChoGGi 10y agoStrange they mention supporting 521 here [1], but on the compare page they only list 384? [1] https://www.yubico.com/2016/05/secure-hardware-vs-open-source/ https://www.yubico.com/2016/05/secure-hardware-vs-open-sourc... Edit: looking at the PIV tools manual they provide; I can see no mention of the tool supporting 521, it fails when I try to generate a key. Looking through the .h files, I do see mentions of p521 ;) int BN_nist_mod_192(BIGNUM *r, const BIGNUM *a, const BIGNUM *p, BN_CTX *ctx); int BN_nist_mod_224(BIGNUM *r, const BIGNUM *a, const BIGNUM *p, BN_CTX *ctx); int BN_nist_mod_256(BIGNUM *r, const BIGNUM *a, const BIGNUM *p, BN_CTX *ctx); int BN_nist_mod_384(BIGNUM *r, const BIGNUM *a, const BIGNUM *p, BN_CTX *ctx); int BN_nist_mod_521(BIGNUM *r, const BIGNUM *a, const BIGNUM *p, BN_CTX *ctx);