I have an RSA signature of 1024 bit where i know the following:

• Public modulus N
• Public exponent (0x03)
• A lot of cypher message

Summary:

An MD5 hash is calculated from a collection of byte and is used as message (M). Our teacher give us more than one signature.

Question:

Can someone give advice to find a pratical way to find a new matching signature from a chosen message?

I have an RSA signature scheme with 1024-bit key where I know the following:

• Public modulus $N$
• Public exponent $e=3$
• A lot of signatures

Summary:

To compute a signature, an MD5 hash is calculated from a collection of byte and the textbook RSA private key function is applied to that. The verification procedure for a signature $S$ is to check that $S^e\bmod N$ is the MD5 hash of the alleged message.

Our teacher give us more than one signature.

Question:

Can someone give advice to find a practical way to find a new matching signature from a chosen message?

I have an RSA signature of 1024 bit where i know the following:

• Public modulus N
• Public exponent (0x03)
• A lot of cypher message

Summary:

An MD5 hash is calculated from a collection of byte and is used as message (M). Our teacher give us more than one signature in order to forge a new matching signature from a chosen message.

Question:

Can someone give advice to find a pratical way to find a new matching signature from a chosen message?

I have an RSA signature of 1024 bit where i know the following:

• Public modulus N
• Public exponent (0x03)
• A lot of cypher message

Summary:

An MD5 hash is calculated from a collection of byte and is used as message (M). Our teacher give us more than one signature.

Question:

Can someone give advice to find a pratical way to find a new matching signature from a chosen message?