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Diffstat (limited to 'src/crypto/x509/pkcs1.go')
-rw-r--r-- | src/crypto/x509/pkcs1.go | 122 |
1 files changed, 122 insertions, 0 deletions
diff --git a/src/crypto/x509/pkcs1.go b/src/crypto/x509/pkcs1.go new file mode 100644 index 000000000..acebe3513 --- /dev/null +++ b/src/crypto/x509/pkcs1.go @@ -0,0 +1,122 @@ +// Copyright 2011 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +package x509 + +import ( + "crypto/rsa" + "encoding/asn1" + "errors" + "math/big" +) + +// pkcs1PrivateKey is a structure which mirrors the PKCS#1 ASN.1 for an RSA private key. +type pkcs1PrivateKey struct { + Version int + N *big.Int + E int + D *big.Int + P *big.Int + Q *big.Int + // We ignore these values, if present, because rsa will calculate them. + Dp *big.Int `asn1:"optional"` + Dq *big.Int `asn1:"optional"` + Qinv *big.Int `asn1:"optional"` + + AdditionalPrimes []pkcs1AdditionalRSAPrime `asn1:"optional,omitempty"` +} + +type pkcs1AdditionalRSAPrime struct { + Prime *big.Int + + // We ignore these values because rsa will calculate them. + Exp *big.Int + Coeff *big.Int +} + +// ParsePKCS1PrivateKey returns an RSA private key from its ASN.1 PKCS#1 DER encoded form. +func ParsePKCS1PrivateKey(der []byte) (key *rsa.PrivateKey, err error) { + var priv pkcs1PrivateKey + rest, err := asn1.Unmarshal(der, &priv) + if len(rest) > 0 { + err = asn1.SyntaxError{Msg: "trailing data"} + return + } + if err != nil { + return + } + + if priv.Version > 1 { + return nil, errors.New("x509: unsupported private key version") + } + + if priv.N.Sign() <= 0 || priv.D.Sign() <= 0 || priv.P.Sign() <= 0 || priv.Q.Sign() <= 0 { + return nil, errors.New("x509: private key contains zero or negative value") + } + + key = new(rsa.PrivateKey) + key.PublicKey = rsa.PublicKey{ + E: priv.E, + N: priv.N, + } + + key.D = priv.D + key.Primes = make([]*big.Int, 2+len(priv.AdditionalPrimes)) + key.Primes[0] = priv.P + key.Primes[1] = priv.Q + for i, a := range priv.AdditionalPrimes { + if a.Prime.Sign() <= 0 { + return nil, errors.New("x509: private key contains zero or negative prime") + } + key.Primes[i+2] = a.Prime + // We ignore the other two values because rsa will calculate + // them as needed. + } + + err = key.Validate() + if err != nil { + return nil, err + } + key.Precompute() + + return +} + +// MarshalPKCS1PrivateKey converts a private key to ASN.1 DER encoded form. +func MarshalPKCS1PrivateKey(key *rsa.PrivateKey) []byte { + key.Precompute() + + version := 0 + if len(key.Primes) > 2 { + version = 1 + } + + priv := pkcs1PrivateKey{ + Version: version, + N: key.N, + E: key.PublicKey.E, + D: key.D, + P: key.Primes[0], + Q: key.Primes[1], + Dp: key.Precomputed.Dp, + Dq: key.Precomputed.Dq, + Qinv: key.Precomputed.Qinv, + } + + priv.AdditionalPrimes = make([]pkcs1AdditionalRSAPrime, len(key.Precomputed.CRTValues)) + for i, values := range key.Precomputed.CRTValues { + priv.AdditionalPrimes[i].Prime = key.Primes[2+i] + priv.AdditionalPrimes[i].Exp = values.Exp + priv.AdditionalPrimes[i].Coeff = values.Coeff + } + + b, _ := asn1.Marshal(priv) + return b +} + +// rsaPublicKey reflects the ASN.1 structure of a PKCS#1 public key. +type rsaPublicKey struct { + N *big.Int + E int +} |