Adb authorization process analysis

adbkey and adbkey.pub

adbkey and adbkey.pub_caibaihui's blog - CSDN blog _what is adbkey file

Experiments have shown that the public key on the mobile phone and the private key on the computer can be successfully paired, even if I modify the public key on the computer later, it will not affect the previous authorization

For example, the mobile phone has a built-in public key, and the paired private key is generated on my computer to complete the authorization

adb pull /data/misc/adb/adb_keys . The public key is stored in it

The authorization pop-up window shows that the RSA key fingerprint should be based on the public key. I don't know how to calculate it.

adb keygen cc can be used to generate RSA public and private keys

This information box will typically display the fingerprint (MD5) of the host's public key, not the host's
public key itself

ADB public key and private key authentication mechanism

Use the following command to generate the host public key fingerprint:

$ awk "{print $1}" < adbkey.pub | openssl base64 -A -d -a | openssl md5 -c | awk "{print $2}" | tr "[:lower:]" "[:upper:]"
23:B2:47:E1:08:DE:5A:3B:58:5A:A5:A6:FA:98:E0:50

Actually, I used this command to find that the generated pop-up window is different from the one I saw, I am ready to give up and find new articles

The result shows that the generated fingerprint information is exactly the same as the fingerprint information on the pop-up window

In general, it is necessary to process base64 and md5 separately

For this, I need to know that the actual key in the file is the base64 encoded part, i.e. long cryptic string of characters.In my case the key field was always followed by the user-host field, i.e. something like [email protected] (also [email protected]), in some strings the case is preceded by a field containing ssh-rsa.

In the latter case, I need to filter on the second field.In Windows, apparently, this is done using a for loop.I also send the output to a file for certUtil to do subsequent digestion, the output of which goes into the file again - containing the key which is no longer base64 encoded but in bytes - and finally hashed with MD5.

Extract the key in the second field of id_rsa.pub into a file named tmp.key_base64: