keytext = key_fingerprint(key, SSH_FP_MD5, SSH_FP_HEX);

		if (setenv(SSH_KEY_FINGERPRINT_ENV_NAME, keytext, 1) == -1) {

			error("%s: setenv: %s", __func__, strerror(errno));

			_exit(1);

		}

		if ((f = tmpfile()) == NULL) {

			error("%s: tmpfile: %s", __func__, strerror(errno));

			_exit(1);

		}

		if (!key_write(key, f)) {

			error("%s: key_write: %s", __func__, strerror(errno));

			_exit(1);

		}

		if ((len = ftell(f)) == -1) {

			error("%s: ftell: %s", __func__, strerror(errno));

			_exit(1);

		}

		if ((keytext = xmalloc(len + 1)) == NULL) {

			error("%s: xmalloc: %s", __func__, strerror(errno));

			_exit(1);

		}

		if ((fseek(f, 0, SEEK_SET)) != 0) {

			error("%s: fseek: %s", __func__, strerror(errno));

			_exit(1);

		}

		if (fread(keytext, 1, len, f) != len) {

			error("%s: fread: %s", __func__, strerror(errno));

			_exit(1);

		}

		keytext[len] = '\0';

		fclose(f);

		if (setenv(SSH_KEY_ENV_NAME, keytext, 1) == -1) {

			error("%s: setenv: %s", __func__, strerror(errno));

			_exit(1);

		}

/*

 * Name of the environment variable containing the incoming key passed

 * to AuthorizedKeysCommand.

 */

#define SSH_KEY_ENV_NAME "SSH_KEY"

/*

 * Name of the environment variable containing the incoming key fingerprint

 * passed to AuthorizedKeysCommand.

 */

#define SSH_KEY_FINGERPRINT_ENV_NAME "SSH_KEY_FINGERPRINT"

The key being used for authentication (the key's type and the key text itself,

separated by a space) will be available in the

.Ev SSH_KEY

environment variable, and the fingerprint of the key will be available in the

.Ev SSH_KEY_FINGERPRINT environment variable.