[Cryptography-dev] Extracting pub key from a csr

[Robert Moskowitz]

I tried that and:

public_bytes = public_key.public_bytes(
     encoding=serialization.Encoding.Raw,
     format=serialization.PublicFormat.Raw)

     public_bytes = public_key.public_bytes(
                    ^^^^^^^^^^
NameError: name 'public_key' is not defined

so I tried

public_bytes = csr.public_key.public_bytes(
     encoding=serialization.Encoding.Raw,
     format=serialization.PublicFormat.Raw)

     public_bytes = csr.public_key.public_bytes(
                    ^^^^^^^^^^^^^^^^^^^^^^^^^^^
AttributeError: 'builtin_function_or_method' object has no attribute 
'public_bytes'

then

public_bytes = csr.public_bytes(
     encoding=serialization.Encoding.DER)

b'0\x81\x8f0C\x02\x01\x000\x101\x0e0\x0c\x06\x03U\x04\x05\x13\x05x12240*0\x05\x06\x03+ep\x03!\x00*,\xeb\xfb\xde\x01|8\xc4\xfdv\xf5\xc8j-\x07;<\xa8OI\x16\x93\x0c\xe2\xb8\xf3\x9b\x9d\xbf\x8fm\xa0\x000\x05\x06\x03+ep\x03A\x00\xc6\xe4~\xbd\xf8\xe0\x01\x9b\xd8\xd1\xcc$\xe9;\x85Gd\x9eb\x98\xdds\xab\x00\xa2\x13-\xb14_\x93bK\x17\xecg\xca/,n\x12\x9eb\x04\x13\xce\xad\xe6\x95\x9fh\xf0\x05\x84\x9f-\xfa3\x06%L\xd0^\x03'

Which looks more like the whole csr, being to large to be 32 bytes.




On 8/29/24 23:15, Alex Gaynor wrote:
> All of our public key types have a public_bytes() method that can be
> used to serialize the key as you wish:
> https://cryptography.io/en/latest/hazmat/primitives/asymmetric/ed25519/#cryptography.hazmat.primitives.asymmetric.ed25519.Ed25519PublicKey.public_bytes
>
> Alex
>
> On Thu, Aug 29, 2024 at 11:12 PM Robert Moskowitz <rgm at htt-consult.com> wrote:
>> I want a variable that is the bits of the public key so that if I print
>> it, I get something like:
>>
>> 0xf32938f7ff6918d5bbdc52483f31e3725875456a9aeb83f915461a5ea629acda
>>
>> or whatever type that I can then change to what I need elsewhere.
>>
>> On 8/29/24 23:02, Alex Gaynor wrote:
>>> You're getting back the public key object for that CSR. When you say
>>> you want the "public key itself" what do you mean?
>>>
>>> Alex
>>>
>>> On Thu, Aug 29, 2024 at 10:54 PM Robert Moskowitz <rgm at htt-consult.com> wrote:
>>>> I have a csr with an eddsa25519 key:
>>>>
>>>> -----BEGIN CERTIFICATE REQUEST-----
>>>> MIGPMEMCAQAwEDEOMAwGA1UEBRMFeDEyMjQwKjAFBgMrZXADIQAqLOv73gF8OMT9
>>>> dvXIai0HOzyoT0kWkwziuPObnb+PbaAAMAUGAytlcANBAMbkfr344AGb2NHMJOk7
>>>> hUdknmKY3XOrAKITLbE0X5NiSxfsZ8ovLG4SnmIEE86t5pWfaPAFhJ8t+jMGJUzQ
>>>> XgM=
>>>> -----END CERTIFICATE REQUEST-----
>>>>
>>>> I want the Pbkey of
>>>>
>>>>            Subject Public Key Info:
>>>>                Public Key Algorithm: ED25519
>>>>                    ED25519 Public-Key:
>>>>                    pub:
>>>>                        e7:3f:5c:a1:b7:78:8a:75:e4:7b:91:4c:0c:1c:48:
>>>>                        d7:f8:06:c1:f1:9d:58:b0:4d:c9:48:7f:3d:1d:bc:
>>>>                        ac:16
>>>>
>>>> I am following
>>>>
>>>> https://cryptography.io/en/3.4.7/x509/reference.html#loading-certificate-signing-requests
>>>> and
>>>> https://cryptography.io/en/3.4.7/x509/reference.html#x-509-csr-certificate-signing-request-builder-object
>>>>
>>>> I tried the following to get the key:
>>>>
>>>> from cryptography.hazmat.primitives import serialization
>>>> from cryptography.hazmat.primitives.asymmetric import ed25519
>>>> from cryptography import x509
>>>> from cryptography.x509.oid import NameOID
>>>> from cryptography.hazmat.primitives.serialization import load_pem_private_key
>>>>
>>>> with open(uacsr, "rb") as f:
>>>>        pem_req_data = f.read()
>>>>        csr = x509.load_pem_x509_csr(pem_req_data)
>>>> csr_pbkey = csr.public_key()
>>>> print(csr_pbkey)
>>>>
>>>> and get:
>>>>
>>>> <cryptography.hazmat.backends.openssl.ed25519._Ed25519PublicKey object at 0x7f513f0d39d0>
>>>>
>>>> not the public key itself.
>>>>
>>>> What am I missing here?
>>>>
>>>> thanks
>>>>
>>>> _______________________________________________
>>>> Cryptography-dev mailing list
>>>> Cryptography-dev at python.org
>>>> https://mail.python.org/mailman/listinfo/cryptography-dev
>>>
>