[openssl-users] Modulus field in text display of a certificate
Tyson at AI.SRI.COM
Sat Apr 4 02:07:20 UTC 2015
I happened to notice what seems to be an output glitch in the textual
output of a certificate.
I received a copy of the QuoVadis Root CA 2 certificate as a file. When
I examined the certificate via
openssl x509 -text -in /tmp/QV.cer (using OpenSSL 1.0.1 14 Mar
2012 as installed in Ubuntu 14.04)
I noticed an extra first zero byte of the Modulus was shown, as compared
to the display of that certificate in Firefox.
> Version: 3 (0x2)
> Serial Number: 1289 (0x509)
> Signature Algorithm: sha1WithRSAEncryption
> Issuer: C=BM, O=QuoVadis Limited, CN=QuoVadis Root CA 2
> Subject Public Key Info:
> Public Key Algorithm: rsaEncryption
> Public-Key: (4096 bit)
I believe there should be 4096/8 = 512 bytes in that modulus. There are
15 bytes shown per line. 512/15 = 34 with a remainder of 2. This
output shows 513 bytes (34 lines plus a remainder of 3).
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