I am not able to find my android signing key on my system, but its in my Phonegap Build account, Is there any option - Phonegap can give me a download link to download that signing key. Or any other way to download that signing key.
No, there is no way for you to obtain your signing key from PhoneGap Build. There are very good legal and technical reasons for this.
In the future back up your key to multiple locations (on & offsite).
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