最初に明示的に指定してみました(次のコマンドを見てください)、パスフレーズの入力を求められます。だから、それは正しいキーファイルを読んでいます。
$ ssh -i ~/.ssh/id_rsa.pub -vT git@github.com
OpenSSH_4.6p1, OpenSSL 0.9.8e 23 Feb 2007
debug1: Connecting to github.com [204.232.175.90] port 22.
debug1: Connection established.
debug1: identity file /c/Users/mohit_thakral/.ssh/id_rsa.pub type 1
debug1: Remote protocol version 2.0, remote software version PANSSH_0.1
debug1: no match: PANSSH_0.1
debug1: Enabling compatibility mode for protocol 2.0
debug1: Local version string SSH-2.0-OpenSSH_4.6
debug1: SSH2_MSG_KEXINIT sent
debug1: SSH2_MSG_KEXINIT received
debug1: kex: server->client aes128-cbc hmac-md5 none
debug1: kex: client->server aes128-cbc hmac-md5 none
debug1: SSH2_MSG_KEX_DH_GEX_REQUEST(1024<1024<8192) sent
debug1: expecting SSH2_MSG_KEX_DH_GEX_GROUP
debug1: SSH2_MSG_KEX_DH_GEX_INIT sent
debug1: expecting SSH2_MSG_KEX_DH_GEX_REPLY
debug1: Host 'github.com' is known and matches the RSA host key.
debug1: Found key in /c/Users/mohit_thakral/.ssh/known_hosts:1
debug1: ssh_rsa_verify: signature correct
debug1: SSH2_MSG_NEWKEYS sent
debug1: expecting SSH2_MSG_NEWKEYS
debug1: SSH2_MSG_NEWKEYS received
debug1: SSH2_MSG_SERVICE_REQUEST sent
debug1: SSH2_MSG_SERVICE_ACCEPT received
debug1: Authentications that can continue: publickey
debug1: Next authentication method: publickey
debug1: Offering public key: /c/Users/mohit_thakral/.ssh/id_rsa.pub
debug1: Server accepts key: pkalg ssh-rsa blen 277
debug1: PEM_read_PrivateKey failed
debug1: read PEM private key done: type <unknown>
Enter passphrase for key '/c/Users/mohit_thakral/.ssh/id_rsa.pub':
debug1: No more authentication methods to try.
Permission denied (publickey).
次に、ファイルなしで試しました。まだ同じ問題。
$ ssh -vT git@github.com
OpenSSH_4.6p1, OpenSSL 0.9.8e 23 Feb 2007
debug1: Connecting to github.com [204.232.175.90] port 22.
debug1: Connection established.
debug1: identity file /c/Users/mohit_thakral/.ssh/identity type -1
debug1: identity file /c/Users/mohit_thakral/.ssh/id_rsa type 1
debug1: identity file /c/Users/mohit_thakral/.ssh/id_dsa type -1
debug1: Remote protocol version 2.0, remote software version PANSSH_0.1
debug1: no match: PANSSH_0.1
debug1: Enabling compatibility mode for protocol 2.0
debug1: Local version string SSH-2.0-OpenSSH_4.6
debug1: SSH2_MSG_KEXINIT sent
debug1: SSH2_MSG_KEXINIT received
debug1: kex: server->client aes128-cbc hmac-md5 none
debug1: kex: client->server aes128-cbc hmac-md5 none
debug1: SSH2_MSG_KEX_DH_GEX_REQUEST(1024<1024<8192) sent
debug1: expecting SSH2_MSG_KEX_DH_GEX_GROUP
debug1: SSH2_MSG_KEX_DH_GEX_INIT sent
debug1: expecting SSH2_MSG_KEX_DH_GEX_REPLY
debug1: Host 'github.com' is known and matches the RSA host key.
debug1: Found key in /c/Users/mohit_thakral/.ssh/known_hosts:1
debug1: ssh_rsa_verify: signature correct
debug1: SSH2_MSG_NEWKEYS sent
debug1: expecting SSH2_MSG_NEWKEYS
debug1: SSH2_MSG_NEWKEYS received
debug1: SSH2_MSG_SERVICE_REQUEST sent
debug1: SSH2_MSG_SERVICE_ACCEPT received
debug1: Authentications that can continue: publickey
debug1: Next authentication method: publickey
debug1: Trying private key: /c/Users/mohit_thakral/.ssh/identity
debug1: Offering public key: /c/Users/mohit_thakral/.ssh/id_rsa
debug1: Server accepts key: pkalg ssh-rsa blen 277
debug1: read PEM private key done: type RSA
debug1: Authentications that can continue: publickey
debug1: Trying private key: /c/Users/mohit_thakral/.ssh/id_dsa
debug1: No more authentication methods to try.
Permission denied (publickey).
次のコマンドも使用して、キーの署名を確認しました。
ssh-keygen -lf ~/.ssh/id_rsa.pub