How to sign and verify a text message (simple usage)
Modify the text message 'aaa' to anything you want.
Choose hash algorithm for signing 'SHA1' or 'SHA256'.
Push 'Sign to this message' button in the left.
Push 'Copy' button in the middle to copy the message to be signed and the generated signature value to verification form in the right.
Push 'Verify this message' in the right.
Then you can see signature verification result in the top of right.
Note for signing in the left form.
See below when you want to specify message and private key to be signed.
In the 'PEM RSA Private Key' text area, you can specify
signer's private key. The format of the key should be
PKCS#1 PEM text formatted and unencrypted RSA private key.
Note for signature verification in the right form.
See below when you want to specify message,
signature value and public key certificate to be verified.
In the 'Verifying Signature' field, you can specify
any signature value to be verified.
Signature value should be hexa decimal encoded 'RSASSA-PKCS1-v1_5' signature.
Currently this supports 'SHA1withRSA' and 'SHA256withRSA' signature algorihtm.
RSA key length have been tested from 512bit to 2048bit for this program.
In the "Signer's Public Key Certificate" field,
you can specify signer's public key certificate to be verified.
The value should be PEM encoded X.509 certificate with RSA public key.
X.509v1 and X.509v3 is available however X.509v2 is not supported now.