j-hpn-ssh/regress/ssh2putty.sh

#!/usr/bin/env sh
#	$OpenBSD: ssh2putty.sh,v 1.5 2019/11/21 05:18:47 tb Exp $

if test "x$1" = "x" -o "x$2" = "x" -o "x$3" = "x"; then
	echo "Usage: ssh2putty hostname port ssh-private-key"
	exit 1
fi

HOST=$1
PORT=$2
KEYFILE=$3

# XXX - support DSA keys too
if grep "BEGIN RSA PRIVATE KEY" $KEYFILE > /dev/null 2>&1; then
	:
else
	echo "Unsupported private key format"
	exit 1
fi

public_exponent=$(
	openssl rsa -noout -text -in $KEYFILE | grep ^publicExponent |
		sed 's/.*(//;s/).*//'
)
test $? -ne 0 && exit 1

modulus=$(
	openssl rsa -noout -modulus -in $KEYFILE | grep ^Modulus= |
		sed 's/^Modulus=/0x/' | tr A-Z a-z
)
test $? -ne 0 && exit 1

echo "rsa2@$PORT:$HOST $public_exponent,$modulus"