diff options
Diffstat (limited to 'libgo/go/crypto/rsa/pkcs1v15.go')
| -rw-r--r-- | libgo/go/crypto/rsa/pkcs1v15.go | 73 |
1 files changed, 36 insertions, 37 deletions
diff --git a/libgo/go/crypto/rsa/pkcs1v15.go b/libgo/go/crypto/rsa/pkcs1v15.go index 5c5f415..3517a8c 100644 --- a/libgo/go/crypto/rsa/pkcs1v15.go +++ b/libgo/go/crypto/rsa/pkcs1v15.go @@ -24,31 +24,32 @@ type PKCS1v15DecryptOptions struct { SessionKeyLen int } -// 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. +// 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. // -// The rand parameter is used as a source of entropy to ensure that encrypting -// the same message twice doesn't result in the same ciphertext. +// The rand parameter is used as a source of entropy to ensure that +// encrypting the same message twice doesn't result in the same +// ciphertext. // -// WARNING: use of this function to encrypt plaintexts other than session keys -// is dangerous. Use RSA OAEP in new protocols. -func EncryptPKCS1v15(rand io.Reader, pub *PublicKey, msg []byte) (out []byte, err error) { +// WARNING: use of this function to encrypt plaintexts other than +// session keys is dangerous. Use RSA OAEP in new protocols. +func EncryptPKCS1v15(rand io.Reader, pub *PublicKey, msg []byte) ([]byte, error) { if err := checkPub(pub); err != nil { return nil, err } k := (pub.N.BitLen() + 7) / 8 if len(msg) > k-11 { - err = ErrMessageTooLong - return + return nil, ErrMessageTooLong } // EM = 0x00 || 0x02 || PS || 0x00 || M em := make([]byte, k) em[1] = 2 ps, mm := em[2:len(em)-len(msg)-1], em[len(em)-len(msg):] - err = nonZeroRandomBytes(ps, rand) + err := nonZeroRandomBytes(ps, rand) if err != nil { - return + return nil, err } em[len(em)-len(msg)-1] = 0 copy(mm, msg) @@ -57,8 +58,7 @@ func EncryptPKCS1v15(rand io.Reader, pub *PublicKey, msg []byte) (out []byte, er c := encrypt(new(big.Int), pub, m) copyWithLeftPad(em, c.Bytes()) - out = em - return + return em, nil } // DecryptPKCS1v15 decrypts a plaintext using RSA and the padding scheme from PKCS#1 v1.5. @@ -69,19 +69,18 @@ func EncryptPKCS1v15(rand io.Reader, pub *PublicKey, msg []byte) (out []byte, er // learn whether each instance returned an error then they can decrypt and // forge signatures as if they had the private key. See // DecryptPKCS1v15SessionKey for a way of solving this problem. -func DecryptPKCS1v15(rand io.Reader, priv *PrivateKey, ciphertext []byte) (out []byte, err error) { +func DecryptPKCS1v15(rand io.Reader, priv *PrivateKey, ciphertext []byte) ([]byte, error) { if err := checkPub(&priv.PublicKey); err != nil { return nil, err } valid, out, index, err := decryptPKCS1v15(rand, priv, ciphertext) if err != nil { - return + return nil, err } if valid == 0 { return nil, ErrDecryption } - out = out[index:] - return + return out[index:], nil } // DecryptPKCS1v15SessionKey decrypts a session key using RSA and the padding scheme from PKCS#1 v1.5. @@ -103,7 +102,7 @@ func DecryptPKCS1v15(rand io.Reader, priv *PrivateKey, ciphertext []byte) (out [ // a random value was used (because it'll be different for the same ciphertext) // and thus whether the padding was correct. This defeats the point of this // function. Using at least a 16-byte key will protect against this attack. -func DecryptPKCS1v15SessionKey(rand io.Reader, priv *PrivateKey, ciphertext []byte, key []byte) (err error) { +func DecryptPKCS1v15SessionKey(rand io.Reader, priv *PrivateKey, ciphertext []byte, key []byte) error { if err := checkPub(&priv.PublicKey); err != nil { return err } @@ -114,7 +113,7 @@ func DecryptPKCS1v15SessionKey(rand io.Reader, priv *PrivateKey, ciphertext []by valid, em, index, err := decryptPKCS1v15(rand, priv, ciphertext) if err != nil { - return + return err } if len(em) != k { @@ -125,7 +124,7 @@ func DecryptPKCS1v15SessionKey(rand io.Reader, priv *PrivateKey, ciphertext []by valid &= subtle.ConstantTimeEq(int32(len(em)-index), int32(len(key))) subtle.ConstantTimeCopy(valid, key, em[len(em)-len(key):]) - return + return nil } // decryptPKCS1v15 decrypts ciphertext using priv and blinds the operation if @@ -213,21 +212,23 @@ var hashPrefixes = map[crypto.Hash][]byte{ crypto.RIPEMD160: {0x30, 0x20, 0x30, 0x08, 0x06, 0x06, 0x28, 0xcf, 0x06, 0x03, 0x00, 0x31, 0x04, 0x14}, } -// SignPKCS1v15 calculates the signature of hashed using RSASSA-PKCS1-V1_5-SIGN from RSA PKCS#1 v1.5. -// Note that hashed must be the result of hashing the input message using the -// given hash function. If hash is zero, hashed is signed directly. This isn't +// SignPKCS1v15 calculates the signature of hashed using +// RSASSA-PKCS1-V1_5-SIGN from RSA PKCS#1 v1.5. Note that hashed must +// be the result of hashing the input message using the given hash +// function. If hash is zero, hashed is signed directly. This isn't // advisable except for interoperability. // -// If rand is not nil then RSA blinding will be used to avoid timing side-channel attacks. +// If rand is not nil then RSA blinding will be used to avoid timing +// side-channel attacks. // -// This function is deterministic. Thus, if the set of possible messages is -// small, an attacker may be able to build a map from messages to signatures -// and identify the signed messages. As ever, signatures provide authenticity, -// not confidentiality. -func SignPKCS1v15(rand io.Reader, priv *PrivateKey, hash crypto.Hash, hashed []byte) (s []byte, err error) { +// This function is deterministic. Thus, if the set of possible +// messages is small, an attacker may be able to build a map from +// messages to signatures and identify the signed messages. As ever, +// signatures provide authenticity, not confidentiality. +func SignPKCS1v15(rand io.Reader, priv *PrivateKey, hash crypto.Hash, hashed []byte) ([]byte, error) { hashLen, prefix, err := pkcs1v15HashInfo(hash, len(hashed)) if err != nil { - return + return nil, err } tLen := len(prefix) + hashLen @@ -248,12 +249,11 @@ func SignPKCS1v15(rand io.Reader, priv *PrivateKey, hash crypto.Hash, hashed []b m := new(big.Int).SetBytes(em) c, err := decryptAndCheck(rand, priv, m) if err != nil { - return + return nil, err } copyWithLeftPad(em, c.Bytes()) - s = em - return + return em, nil } // VerifyPKCS1v15 verifies an RSA PKCS#1 v1.5 signature. @@ -261,17 +261,16 @@ func SignPKCS1v15(rand io.Reader, priv *PrivateKey, hash crypto.Hash, hashed []b // function and sig is the signature. A valid signature is indicated by // returning a nil error. If hash is zero then hashed is used directly. This // isn't advisable except for interoperability. -func VerifyPKCS1v15(pub *PublicKey, hash crypto.Hash, hashed []byte, sig []byte) (err error) { +func VerifyPKCS1v15(pub *PublicKey, hash crypto.Hash, hashed []byte, sig []byte) error { hashLen, prefix, err := pkcs1v15HashInfo(hash, len(hashed)) if err != nil { - return + return err } tLen := len(prefix) + hashLen k := (pub.N.BitLen() + 7) / 8 if k < tLen+11 { - err = ErrVerification - return + return ErrVerification } c := new(big.Int).SetBytes(sig) |