**Any private key value that you enter or we generate is not stored on this site, this tool is provided via an HTTPS URL to ensure that private keys cannot be stolen, for extra security run this software on your network, no cloud dependency**

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OpenSSL Commands for Generatoing DSA Param, Singing File & verify File

openssl dsaparam 2048 < /dev/random > dsa_param.pem

openssl gendsa dsa_param.pem -out dsa_priv.pem

openssl dsa -in dsa_priv.pem -pubout -out dsa_pub.pem

# DSA system now made up of: dsa_param.pem, dsa_pub.pem, dsa_priv.pem

echo "foobar" > foo.txt

openssl sha1 < foo.txt > foo.txt.sha1

openssl dgst -dss1 -sign dsa_priv.pem foo.txt.sha1 > foo.txt.sig

openssl dgst -dss1 -verify dsa_pub.pem -signature foo.txt.sig foo.txt.sha1

DSA (Digital Signature Algorithm)

DSA is a variant on the ElGamal and Schnorr algorithms creates a 320 bit signature, but with 512-1024 bit security security again rests on difficulty of computing discrete logarithms has been quite widely accepted

DSA Key Generation

firstly shared global public key values (p,q,g) are chosen:

choose a large prime p = 2 power L

where L= 512 to 1024 bits and is a multiple of 64

choose q, a 160 bit prime factor of p-1

choose g = h power (p-1)/q

for any h1

then each user chooses a private key and computes their public key:

choose x compute y = g power x(mod p)

DSA key generation is related to, but somewhat more complex than El Gamal. Mostly because of the use of the secondary 160-bit modulus q used to help speed up calculations and reduce the size of the resulting signature.

DSA Signature Creation and Verification

to sign a message M

generate random signature key k, k compute

r = (g power k(mod p))(mod q)

s = k-1.SHA(M)+ x.r (mod q)

send signature (r,s) with message

to verify a signature, compute:

w = s-1(mod q)

u1= (SHA(M).w)(mod q)

u2= r.w(mod q)

v = (g power u1.y power u2(mod p))(mod q)

if v=r then the signature is verified