To Generate Private Key openssl genrsa -out privatekey.pem 2048 To Sign openssl dgst -sha256 -sign privatekey.pem -out data.txt.signature data.txt To Generate The Public Key dgst -verify requires the public key openssl rsa -in privatekey.pem -outform PEM -pubout -out publickey.pem To Verify openssl dgst -sha256 -verify publickey.pem -signature data.txt.signature data.txt In case of success: prints “Verified … Read more
openssl dgst -verify foo.pem expects that foo.pem contains the “raw” public key in PEM format. The raw format is an encoding of a SubjectPublicKeyInfo structure, which can be found within a certificate; but openssl dgst cannot process a complete certificate in one go. You must first extract the public key from the certificate: openssl x509 … Read more
The wikipedia article is a bit difficult to understand. In a nutshell, you can think of a Rainbow Table as a large dictionary with pre-calculated hashes and the passwords from which they were calculated. The difference between Rainbow Tables and other dictionaries is simply in the method how the entries are stored. The Rainbow table … Read more
(Expanding more than I feel is appropriate for an edit.) PKCS1, available in several versions as rfcs 2313 2437 3447 and 8017, is primarily about using the RSA algorithm for cryptography including encrypting decrypting signing and verifying. But since crypto is often used between systems or at least programs it is convenient to have a … Read more
What you describe is called a collision. Collisions necessarily exist, since SHA-1 accepts many more distinct messages as input that it can produce distinct outputs (SHA-1 may eat any string of bits up to 2^64 bits, but outputs only 160 bits; thus, at least one output value must pop up several times). This observation is … Read more
import ( “crypto/md5” “encoding/hex” ) func GetMD5Hash(text string) string { hash := md5.Sum([]byte(text)) return hex.EncodeToString(hash[:]) }
The short answer to your question is: SHA-1 is as secure as you can get. MD5 would be fine too, even MD4; but it could make some investors nervous. For public relations, it is best to use a “better” hash function, e.g. SHA-256, even if you truncate its output to 160 or 128 bits (to … Read more
xor is a dangerous default function to use when hashing. It is better than and and or, but that doesn’t say much. xor is symmetric, so the order of the elements is lost. So “bad” will hash combine the same as “dab”. xor maps pairwise identical values to zero, and you should avoid mapping “common” … Read more
Most basic and general explanation: cryptography is all about number theory, and all integer numbers (except 0 and 1) are made up of primes, so you deal with primes a lot in number theory. More specifically, some important cryptographic algorithms such as RSA critically depend on the fact that prime factorization of large numbers takes … Read more