Package rsa
import "crypto/rsa"
This package implements RSA encryption as specified in PKCS#1.
Package files
pkcs1v15.go rsa.gofunc DecryptOAEP
func DecryptOAEP(hash hash.Hash, rand io.Reader, priv *PrivateKey, ciphertext []byte, label []byte) (msg []byte, err os.Error)
DecryptOAEP decrypts ciphertext using RSA-OAEP. If rand != nil, DecryptOAEP uses RSA blinding to avoid timing side-channel attacks.
func DecryptPKCS1v15
func DecryptPKCS1v15(rand io.Reader, priv *PrivateKey, ciphertext []byte) (out []byte, err os.Error)
DecryptPKCS1v15 decrypts a plaintext using RSA and the padding scheme from PKCS#1 v1.5. If rand != nil, it uses RSA blinding to avoid timing side-channel attacks.
func DecryptPKCS1v15SessionKey
func DecryptPKCS1v15SessionKey(rand io.Reader, priv *PrivateKey, ciphertext []byte, key []byte) (err os.Error)
DecryptPKCS1v15SessionKey decrypts a session key using RSA and the padding scheme from PKCS#1 v1.5. If rand != nil, it uses RSA blinding to avoid timing side-channel attacks. It returns an error if the ciphertext is the wrong length or if the ciphertext is greater than the public modulus. Otherwise, no error is returned. If the padding is valid, the resulting plaintext message is copied into key. Otherwise, key is unchanged. These alternatives occur in constant time. It is intended that the user of this function generate a random session key beforehand and continue the protocol with the resulting value. This will remove any possibility that an attacker can learn any information about the plaintext. See “Chosen Ciphertext Attacks Against Protocols Based on the RSA Encryption Standard PKCS #1”, Daniel Bleichenbacher, Advances in Cryptology (Crypto '98),
func EncryptOAEP
func EncryptOAEP(hash hash.Hash, rand io.Reader, pub *PublicKey, msg []byte, label []byte) (out []byte, err os.Error)
EncryptOAEP encrypts the given message with RSA-OAEP. The message must be no longer than the length of the public modulus less twice the hash length plus 2.
func EncryptPKCS1v15
func EncryptPKCS1v15(rand io.Reader, pub *PublicKey, msg []byte) (out []byte, err os.Error)
EncryptPKCS1v15 encrypts the given message with RSA and the padding scheme from PKCS#1 v1.5. The message must be no longer than the length of the public modulus minus 11 bytes. WARNING: use of this function to encrypt plaintexts other than session keys is dangerous. Use RSA OAEP in new protocols.
func SignPKCS1v15
func SignPKCS1v15(rand io.Reader, priv *PrivateKey, hash PKCS1v15Hash, hashed []byte) (s []byte, err os.Error)
SignPKCS1v15 calcuates the signature of hashed using RSASSA-PSS-SIGN from RSA PKCS#1 v1.5. Note that hashed must be the result of hashing the input message using the given hash function.
func VerifyPKCS1v15
func VerifyPKCS1v15(pub *PublicKey, hash PKCS1v15Hash, hashed []byte, sig []byte) (err os.Error)
VerifyPKCS1v15 verifies an RSA PKCS#1 v1.5 signature. hashed is the result of hashing the input message using the given hash function and sig is the signature. A valid signature is indicated by returning a nil error.
type DecryptionError
A DecryptionError represents a failure to decrypt a message. It is deliberately vague to avoid adaptive attacks.
type DecryptionError struct{}
func (DecryptionError) String
func (DecryptionError) String() string
type MessageTooLongError
MessageTooLongError is returned when attempting to encrypt a message which is too large for the size of the public key.
type MessageTooLongError struct{}
func (MessageTooLongError) String
func (MessageTooLongError) String() string
type PKCS1v15Hash
Due to the design of PKCS#1 v1.5, we need to know the exact hash function in use. A generic hash.Hash will not do.
type PKCS1v15Hash int
const (
HashMD5 PKCS1v15Hash = iota
HashSHA1
HashSHA256
HashSHA384
HashSHA512
)
type PrivateKey
A PrivateKey represents an RSA key
type PrivateKey struct {
PublicKey // public part.
D *big.Int // private exponent
P, Q *big.Int // prime factors of N
}
func GenerateKey
func GenerateKey(rand io.Reader, bits int) (priv *PrivateKey, err os.Error)
GenerateKeyPair generates an RSA keypair of the given bit size.
func (PrivateKey) Validate
func (priv PrivateKey) Validate() os.Error
type PublicKey
A PublicKey represents the public part of an RSA key.
type PublicKey struct {
N *big.Int // modulus
E int // public exponent
}
type VerificationError
A VerificationError represents a failure to verify a signature. It is deliberately vague to avoid adaptive attacks.
type VerificationError struct{}
func (VerificationError) String
func (VerificationError) String() string