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A comment on Patch Critical Cryptographic Vulnerability in Microsoft Windows [pdf]. Parent comment

Re:Patch Critical Cryptographic Vulnerability in Microsoft W... by ASN1 on Wednesday January 15, 2020 @10:33AM (#22055063)
Try pasting your cert into https://lapo.it/asn1js/

You can see all the parts in the blob:

        OBJECT IDENTIFIER 1.2.840.10045.2.1 ecPublicKey (ANSI X9.62 public key type)
        SEQUENCE (6 elem)
          INTEGER 1
          SEQUENCE (2 elem)
            OBJECT IDENTIFIER 1.2.840.10045.1.1 prime-field (ANSI X9.62 field type)
            INTEGER (256 bit) 1157920892373161954235709850086879078532699846656405640394575840079088…
          SEQUENCE (2 elem)
            OCTET STRING (32 byte) 0000000000000000000000000000000000000000000000000000000000000000
            OCTET STRING (32 byte) 0000000000000000000000000000000000000000000000000000000000000007
          OCTET STRING (65 byte) 0479BE667EF9DCBBAC55A06295CE870B07029BFCDB2DCE28D959F2815B16F81798483A…
          INTEGER (256 bit) 1157920892373161954235709850086879078528375642790749043826051631415181…
          INTEGER 1
This will help you understand the ASN.1 encoding of a cert: http://luca.ntop.org/Teaching/Appunti/asn1.html
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Re:Patch Critical Cryptographic Vulnerability in Microsoft W... by benth on Wednesday January 15, 2020 @02:17PM (#22057454)
The parent comment is wondering about the structure of the signature and if different curve parameters can be specified for it. How can explicit curve parameters be specified in an ECDSA signature? ecdsaWithSHA256, at least, is simply two bigints. There's no spot for specifying explicit parameters.
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Re:Patch Critical Cryptographic Vulnerability in Microsoft W... by tptacek on Wednesday January 15, 2020 @02:34PM (#22057622)
This is answered upthread and in RFC 5480: the AlgorithmIdentifier has an ANY OPTIONAL field for parameters.
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Re:Patch Critical Cryptographic Vulnerability in Microsoft W... by benth on Wednesday January 15, 2020 @03:09PM (#22057953)
Missed that. Thank you!
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