diff --git a/src/OpenSSL.jl b/src/OpenSSL.jl
index 234df29..b770877 100644
--- a/src/OpenSSL.jl
+++ b/src/OpenSSL.jl
@@ -21,6 +21,8 @@ include("certs.jl")
 
 include("flow_control.jl")
 
+include("errors.jl")
+
 import Base.read
 function read(client::SSLClient)
     buf = Vector{UInt8}(undef, 64)
diff --git a/src/errors.jl b/src/errors.jl
index 5662fb9..e205f6d 100644
--- a/src/errors.jl
+++ b/src/errors.jl
@@ -5,3 +5,40 @@ ERR_pop_to_mark() = ccall((:ERR_pop_to_mark, libssl), Cint, ())
 ERR_set_mark() = ccall((:ERR_set_mark, libssl), Cint, ())
 ERR_print_errors(file_ptr) =
     ccall((:ERR_print_errors, libssl), Cvoid, (Ptr{Cvoid},), file_ptr)
+
+@enum SSL_VERIFY_ERROR begin
+    X509_V_OK = 0
+    X509_V_ERR_UNABLE_TO_GET_ISSUER_CERT = 2
+    X509_V_ERR_UNABLE_TO_GET_CRL = 3
+    X509_V_ERR_UNABLE_TO_DECRYPT_CERT_SIGNATURE = 4
+    X509_V_ERR_UNABLE_TO_DECRYPT_CRL_SIGNATURE = 5
+    X509_V_ERR_UNABLE_TO_DECODE_ISSUER_PUBLIC_KEY = 6
+    X509_V_ERR_CERT_SIGNATURE_FAILURE = 7
+    X509_V_ERR_CRL_SIGNATURE_FAILURE = 8
+    X509_V_ERR_CERT_NOT_YET_VALID = 9
+    X509_V_ERR_CERT_HAS_EXPIRED = 10
+    X509_V_ERR_CRL_NOT_YET_VALID = 11
+    X509_V_ERR_CRL_HAS_EXPIRED = 12
+    X509_V_ERR_ERROR_IN_CERT_NOT_BEFORE_FIELD = 13
+    X509_V_ERR_ERROR_IN_CERT_NOT_AFTER_FIELD = 14
+    X509_V_ERR_ERROR_IN_CRL_LAST_UPDATE_FIELD = 15
+    X509_V_ERR_ERROR_IN_CRL_NEXT_UPDATE_FIELD = 16
+    X509_V_ERR_OUT_OF_MEM = 17
+    X509_V_ERR_DEPTH_ZERO_SELF_SIGNED_CERT = 18
+    X509_V_ERR_SELF_SIGNED_CERT_IN_CHAIN = 19
+    X509_V_ERR_UNABLE_TO_GET_ISSUER_CERT_LOCALLY = 20
+    X509_V_ERR_UNABLE_TO_VERIFY_LEAF_SIGNATURE = 21
+    X509_V_ERR_CERT_CHAIN_TOO_LONG = 22
+    X509_V_ERR_CERT_REVOKED = 23
+    X509_V_ERR_INVALID_CA = 24
+    X509_V_ERR_PATH_LENGTH_EXCEEDED = 25
+    X509_V_ERR_INVALID_PURPOSE = 26
+    X509_V_ERR_CERT_UNTRUSTED = 27
+    X509_V_ERR_CERT_REJECTED = 28
+    X509_V_ERR_SUBJECT_ISSUER_MISMATCH = 29
+    X509_V_ERR_AKID_SKID_MISMATCH = 30
+    X509_V_ERR_AKID_ISSUER_SERIAL_MISMATCH = 31
+    X509_V_ERR_KEYUSAGE_NO_CERTSIGN = 32
+    # Unused
+    X509_V_ERR_APPLICATION_VERIFICATION = 50
+end